HAYAKAWA MASASHI
| Emeritus Professor etc. | Emeritus Professor |
Researcher Information
Educational Background
Research Activity Information
Paper
- Space Weather and Seismo-Electromagnetics
K. Yumoto; S. Ikemoto; M.G. Cardinal; T. Uozumi; S. Abe; G. Maeda; M. Hayakawa; K. Hattori; K. Shiokawa; J. Y. Liu; M. Ruhimat; S. Saroso; M. Husni; D. S. Widarto; D. McNamara; E.G. Ramos; R. E; S. Otadoy; ND MAGDAS Group
Int'l Workshop on Space and Lithosphere Environment Changes in Asia, -, -, 24, Mar. 2008, Peer-reviwed
International conference proceedings, English - Some results of seismo-electromagnetic research at LAPAN, Indonesia
S. Saroso; K. Hattori; M. Hayakawa; K. Shiokawa; K. Yumoto; J. Y. Liu
Int'l Workshop on Space and Lithosphere Environment Changes in Asia, -, -, 29, Mar. 2008, Peer-reviwed
International conference proceedings, English - Ground-based Electromagnetic Monitoring in the Western Sunda Arc, Indonesia: Recent Progress and Some Results
Djedi S. Widarto; Katsumi Hattori; Febty Febriani; Hendri Subakti; Masturyono; Kenji Ohta; Masashi Hayakawa; Seiya Uyeda
Int'l Workshop on Space and Lithosphere Environment Changes in Asia, -, -, 30, Mar. 2008, Peer-reviwed
International conference proceedings, English - Review on NASDA's Earthquake Remote Sensing Frontier Project
M. Hayakawa
Int'l Workshop on Seismo-Electromagnetic Observation Satellite, -, -, -, Feb. 2008, Peer-reviwed
International conference proceedings, English - Seismo-Electromagnetics: Review
M. Hayakawa
Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), -, -, -, Nov. 2007, Peer-reviwed
International conference proceedings, English - Space Weather and Seismo-Electromagnetics
K.Yumoto; H. Kawano; A. Yoshikawa; S. Ikemoto; G. Maeda; M. Hayakawa; K. Hattori; Tiger Liu; S. Saroso; M. Husni; D. Widarto; E. G. Ramos; C. M; G. Cardinal; R. E; S. Otadoy; MAGDAS GRoup
Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), -, -, 19, Nov. 2007, Peer-reviwed
International conference proceedings, English - Seismo-electromagnetic signatures possibly related to the Sumatra megathrust earthquakes of 26 December 2004 and 28 March 2005
Sarmoko Saroso; K. Hattori; M. Hayakawa; K. Shiokawa; K. Yumoto
Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), -, -, 28, Nov. 2007, Peer-reviwed
International conference proceedings, English - Electromagnetic monitoring for crustal activity in Indonesia
K. Hattori; D. S. Widarto; S. Saroso; M. Nishihashi; C. Yoshino; D. Kaida; E. Z. Gaffar; Y. Sudrajat; K. Yumoto; M. Husni; H. Subakti; K. Shiokawa; M. Hayakawa
Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), -, -, 44, Nov. 2007, Peer-reviwed
International conference proceedings, English - Interaction of unstable modes of ionospheric plasma and modes of neutral atmosphere
Yu. G. Rapoport; M. Hayakawa; O. E. Gorynyan; V. M. Ivchenko; A. K. Fedorenko; Yu. A. Selivanov
Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), -, -, 49, Nov. 2007, Peer-reviwed
International conference proceedings, English - FLR-model verification based on the sunrise-sunset ULF geomagnetic features
L. Alperovich; E. Fedorov; M. Hayakawa; C. Price; M. Merzer; A. Zomer; N. Yagova
International CAWSES Symposium, -, -, P1-090, Oct. 2007, Peer-reviwed
International conference proceedings, English - Modeling of solar flare induced D region perturbation in the ionosphere and comparison with VLF amplitude observation
Y. T. Tanaka; T. Terasawa; M. Hayakawa; M. Yoshida; T. Horie; T. Minoshima
International CAWSES Symposium, -, -, P3-091, Oct. 2007, Peer-reviwed
International conference proceedings, English - Mesoscale lightning in west African squall lines and its global detection with ELF measurements
Y. Hobara; E. Williams; R. Boldi; G. Satori; J. Bor; W. Lyons; T. Nelson; M. Hayakawa; C. Price; E. Greenberg; N. Nathow; B. Russell; V. Mushtak
13th International Conference on Atmospheric Electricity, -, -, PS5-10, Aug. 2007, Peer-reviwed
International conference proceedings, English - Cellular automation modeling of sprite fine structure
M. Hayakawa; D. I. Iudin; E. A. Mareev; V. Yu. Trakhtengerets
13th International Conference on Atmospheric Electricity, -, -, PS7-3, Aug. 2007, Peer-reviwed
International conference proceedings, English - Structure and dynamics of ionospheric perturbations associated with the Sumatra earthquake in December, 2004: Ground and satellite observation of VLF transmitter signals
M. Hayakawa; T. Horie; T. Yamauchi; O. A. Molchanov; M. Parrot
AOGS 2007, -, -, IWG03-A0003, Jul. 2007, Peer-reviwed
International conference proceedings, English - Precursory phenomena using ULF electromagnetic wave in possible association with huge earthquakes
K. Ohta; J. Izutsu; N. Watanabe; M. Hayakawa
AOGS 2007, -, -, IWG03-A0002, Jul. 2007, Peer-reviwed
International conference proceedings, English - VLF transmitter signals received on satellite for global diagnostics of ionospheric perturbations associated with seismicity
A. Rozhnoi; O. Molchanov; M. Solovieva; O. Akentieva; J. J. Berthelier; M. Parrot; F. Lefeuvre; M. Hayakawa; T. Yamauchi; P. F. Biagi; L. Castellana
IUGG XXIV General Assembly, -, -, -, Jul. 2007, Peer-reviwed
International conference proceedings, English - Observation evidences of Atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra
A. Rozhnoi; M. Solovieva; O. Molchanov; P.F. Biagi; M. Hayakawa
IUGG XXIV General Assembly, -, -, -, Jul. 2007, Peer-reviwed
International conference proceedings, English - Anomalies in VLF radio intensities related to seismicity during November-December 2004: a comparison of ground and Demeter satellite results
P.F. Biagi; L. Castellana; T. Maggipinto; R. Piccolo; A. Minafra; A. Ermini; V. Capozzi; M. Solovieva; O. Molchanov; M. Hayakawa; A. Rozhnoi
IUGG XXIV General Assembly, -, -, -, Jul. 2007, Peer-reviwed
International conference proceedings, English - Seismo Electromagnetics: Review
M. Hayakawa
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 1, Jul. 2007, Peer-reviwed
International conference proceedings, English - Interferometric Observation of Over-horizon VHF Signals Associated with Earthquakes
Y. Yasuda; T. Gotoh; M. Hayakawa; Y. Ida; N. Yonaiguchi
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 35, Jul. 2007, Peer-reviwed
International conference proceedings, English - On the statistical correlation of over-horizon VHF signals with meteorological radio ducting and seismicity
N. Yonaiguchi; Y. Ida; M. Hayakawa
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 36, Jul. 2007, Peer-reviwed
International conference proceedings, English - The wave-like structures of ionospheric perturbation associated with Sumatra earthquake of 26 December 2004, as revealed from VLF observations in Japan of NWC signals
T. Horie; T. Yamauchi; M. Yoshida; M. Hayakawa
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 37, Jul. 2007, Peer-reviwed
International conference proceedings, English - Interpretation of VLF/LF terminator time and its application to seismogenic studies
M. Yoshida; T. Yamauchi; S. Maekawa; T. Horie; M. Hayakawa; O. Soloviev
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 38, Jul. 2007, Peer-reviwed
International conference proceedings, English - Detection of seismo-ionospheric perturbations on the basis of receprion of VLF transmitter signals on the satellite, DEMETER.
F. Muto; M. Yoshida; T. Horie; M. Hayakawa; M. Parrot
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 39, Jul. 2007, Peer-reviwed
International conference proceedings, English - Fractal analysis results of electromagnetic emissions (ULF and VHF) associated with earthquakes.
Y. Ida; N. Yonaiguchi; S. Masuda; M. Hayakawa
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 40, Jul. 2007, Peer-reviwed
International conference proceedings, English - Singular Spectral Analysis and Principal Component Analysis for Signal Discrimination of ULF Geomagnetic Data Associated with 2000 Izu Island Earthquake Swarm
K. Hattori; A. Serita; D. Kaida; C. Yoshino; M. Hayakawa; N. Isezaki
Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, -, -, 46, Jul. 2007, Peer-reviwed
International conference proceedings, English - Characteristics of VHF over-horizon signals possibly related to impending earthquakes and a mechanism of seismo-atmospheric perturbations
M. Hayakawa; V. V. Surkov; Y. Fukumoto; N. Yonaiguchi
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 69, 9, 1057-1062, Jul. 2007, Peer-reviwed, There have been evidences of the presence of atmospheric disturbances associated with earthquakes, as based on the reception of over-horizon VHF signals. In this paper we propose a generation mechanism of such atmospheric perturbation based on the changes in geochemical quantities associated with earthquakes. (c) 2007 Elsevier Ltd. All rights reserved.
Scientific journal, English - The wave-like structures of ionospheric perturbation associated with Sumatra earthquake of 26 December 2004, as revealed from VLF observation in Japan of NWC signals
Takumi Horie; Takeshi Yamauchi; Mari Yoshida; Masashi Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 69, 9, 1021-1028, Jul. 2007, Peer-reviwed, The observations of subionospheric VLF waves from the Australian VLF transmitter NWC (frequency = 19.8 kHz) at the Japanese receiving stations Chofu, Chiba and Kochi have been utilized to identify a possible precursor of ionospheric perturbations to the huge Sumatra earthquake of 26 December 2004. The VLF amplitude data at Japanese stations have indicated the depression in amplitude and also the enhancement in nighttime amplitude fluctuation before the earthquake. The nighttime fluctuation is composed of wave-like structures, and the wavelet analysis and cross-correlation analyses have been performed for those fluctuations. A significant enhancement in the fluctuation spectra in the period 20-30 min to similar to 100min (the frequency range of atmospheric gravity waves) is observed only before the earthquake. Then, the wave-like structures tend to propagate from the NWC-Kochi path to NWC-Chiba path with the time delay of similar to 2 h, and so the wave propagation speed is estimated as similar to 20 m/s. This finding might be important when we think of lithosphere-ionosphere coupling mechanism. (c) 2007 Elsevier Ltd. All rights reserved.
Scientific journal, English - Monitoring of ULF (ultra-low-frequency) geomagnetic variations associated with earthquakes
Masashi Hayakawa; Katsumi Hattori; Kenji Ohta
SENSORS, MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL, 7, 7, 1108-1122, Jul. 2007, Peer-reviwed, ULF (ultra-low-frequency) electromagnetic emission is recently recognized as one of the most promising candidates for short-term earthquake prediction. This paper reviews previous convincing evidence on the presence of ULF emissions before a few large earthquakes. Then, we present our network of ULF monitoring in the Tokyo area by describing our ULF magnetic sensors and we finally present a few, latest results on seismogenic electromagnetic emissions for recent large earthquakes with the use of sophisticated signal processings.
Scientific journal, English - ULF electromagnetic noise due to random variations of background atmospheric current and conductivity
V. V. Surkov; M. Hayakawa
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, AMER GEOPHYSICAL UNION, 112, D11, doi: 10.1029/2006JD007788, Jun. 2007, Peer-reviwed, [1] A mechanism of ULF electromagnetic noise generation due to random fluctuations of the atmospheric conductivity and background currents was examined. Current fluctuations similar to 1/f noise, or flicker noise, are assumed to develop inside large-scale atmospheric inhomogeneities such as thunderstorms, hurricanes, mesoscale convective systems, etc. The random current fields are assumed to be steady, uniform, and isotropic inside the inhomogeneity, which, in turn, implies that the spectral density of the process is delta correlated. A correlation radius of the random process is supposed to be dependent on gas transfer and on the acoustic wave propagation due to pressure and temperature gradients in the atmosphere. To relate the electromagnetic spectra with current fields, a transfer matrix was found, and then the correlation matrix and power spectra of the random electromagnetic field were calculated. It was shown that the large-scale random fluctuations of the atmospheric background current are capable of sustaining generation of the ULF magnetic noise that can be detected on the ground. The spectral index of magnetic noise was found to be 1.5, which is consistent with observation in the 10(-2) to 10(-4) Hz frequency range.
Scientific journal, English - Subionospheric VLF/LF monitoring of ionospheric perturbations for the 2004 Mid-Niigata earthquake and their structure and dynamics
Takeshi Yamauchi; Shinko Maekawa; Takumi Horie; Masashi Hayakawa; O. Soloviev
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 69, 7, 793-802, May 2007, Peer-reviwed, This paper reports on the detailed spatial structure and temporal dynamics of the ionospheric perturbations associated with the huge 2004 Mid-Niigata earthquake in Japan. The terminator time method in VLF/LF subionospheric propagation has been used to deduce the presence and dynamics of the seismo-ionospheric perturbations by making full use of our Japanese VLF/LF network observations. It is found that significant shifts were observed in terminator time for some selected paths, a few to several days before the earthquake, and we obtained the anisotropic shape of the inferred ionospheric perturbation likely elongated along the fault lines there. The temporal dynamics of inhomogeneity of the perturbations is suggested on the basis of a comparison of the observed terminator time shift and theoretical full-wave computations (2D FDTD and 3D full-wave scattering). (c) 2007 Elsevier Ltd. All rights reserved.
Scientific journal, English - Decreases in the electric intensity of VLF radio signals and possible connections with the seismicity
Biagi, P.F; Castellana, L; Maggipinto, T; Piccolo, R; Minafra, A; Ermini, A; Capozzi, V; Solovieva, M; Molchanov, O; Hayakawa, M
EGU General Assembly 2007, -, -, EGU2007-A-01081, Apr. 2007, Peer-reviwed
International conference proceedings, English - ULF/ELF magnetic field variations in atmosphere probably induced by seismisity
Schekotov, A; Molchanov, O; Fedorov, E; Chebrov, V; Sinitsin, V; Gordeev, E; Belyaev, G; Hayakawa, M
EGU General Assembly 2007, -, -, EGU2007-A-01199, Apr. 2007, Peer-reviwed
International conference proceedings, English - Magnetic location of ionosphere and lithosphere sources of ULF geomagnetic disturbances
Kopytenko, Yu; Ismaguilov, V; Hattory, K; Hayakawa, M
EGU General Assembly 2007, -, -, EGU2007-A-03492, Apr. 2007, Peer-reviwed
International conference proceedings, English - Extraction of the earthquake precursory signatures from fractal characteristics of ULF emissions
Smirnova, N; Hayakawa, M; Uritsky, V; Mezentsev, A
EGU General Assembly 2007, -, -, EGU2007-A-10340, Apr. 2007, Peer-reviwed
International conference proceedings, English - Mesoscale lightning in west African squall lines and its global detection with ELF measurements
Hobara, Y; Williams, E; Boldi, R; Satori, G; Bor, J; Lyons, W; Nelson, T; Hayakawa, M; Nathou, N; Russell, B
EGU General Assembly 2007, -, -, EGU2007-A-05344, Apr. 2007, Peer-reviwed
International conference proceedings, English - On the statistical correlation of over-horizon VHF signals with meteorological radio ducting and seismicity
N. Yonaiguchi; Y. Ida; M. Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 69, 6, 661-674, Apr. 2007, Peer-reviwed, With the use of a complete 1 year (2005) data on over-horizon VHF signals (transmitted in Sendai and received in Chofu), we have investigated the statistical significance on the correlation of VHF signal characteristics (amplitude and variance) with meteorological radio duct effect and seismicity (earthquakes). It is found that the meteorological radio duct effect is rather predominant in July-September. On the other hand, over-horizon VHF signals are found to be correlated with earthquakes in other seasons. Especially, when we narrow our analysis area just around the middle region of the great-circle path, we have always significant correlation between VHF signal characteristics (average, median intensity or variance) with seismicity in any months of the year, with exceeding the confidence level. (c) 2007 Elsevier Ltd. All rights reserved.
Scientific journal, English - Cellular automaton modeling of mesospheric optical emissions: Sprites
M. Hayakawa; D. I. Iudin; E. A. Mareev; V. Y. Trakhtengerts
PHYSICS OF PLASMAS, AMER INST PHYSICS, 14, 4, 042902 1-6, Apr. 2007, Peer-reviwed, This paper presents a new attempt to model two-dimensional mesospheric optical emissions named sprites with the use of a cellular automaton network. A large-scale model of sprites based on the phenomenological percolation-like probabilistic approach is developed to model streamer discharges in sprites. It is shown that a sprite is a self-affine structure rather than a simple fractal one, and that this self-affine structure is tightly connected with directed percolation phenomena. The system is found to evolve in the vicinity of the percolation threshold, which results in a wide variety of sprite characteristics even under similar initial conditions. The approach developed allows us to estimate a maximum size of the discharge pattern to be formed. (c) 2007 American Institute of Physics.
Scientific journal, English - Simulation of surface discharge dynamics by means of cellular automata
A. S. Adalev; M. Hayakawa; N. V. Korovkin; D. I. Iudin; V. Yu. Trakhtengerts
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 101, 8, 083302, Apr. 2007, Peer-reviwed, A dynamic model of a creeping discharge over a dielectric surface is presented. A discharge area (above a dielectric sheet separating a metal needle from a ground plain electrode) is presented as a system of gas sphere cells covering the dielectric. A discharge tree (conducting cluster) is represented by a nonlinear circuit consisting of capacitances, nonlinear conductances, and controlled sources. The sources simulate the potential caused by the needle electrode and free charge located in the neighboring cells. The coefficients for the controlled sources and cell capacitances are determined from the results of static field calculation. The effects of electron drift, impact ionization, and photoionization are involved into the conductance model. Physical parameters of the latter two processes are deduced from the experimental data available in the literature. The criteria for cell initiation are obtained for different applied voltages such that dynamic characteristics of the model correspond to the experimental ones. The experimental results for the nanosecond discharges are used here considering the streamer phase of discharge development. Further improvement of the conductance model is discussed with respect to plasma heating up to the temperatures enough for the streamer-to-leader transition. In addition to discharge patterns which were created to be similar to experimental Lichtenberg figures, the model allows us to determine such local properties of the discharge as current, voltage drop, loss, field, and charge distribution. (c) 2007 American Institute of Physics.
Scientific journal, English - Solar flare induced D region perturbation in the ionosphere, as revealed from a short-distance VLF propagation path
Y. Todoroki; S. Maekawa; T. Yamauchi; T. Horie; M. Hayakawa
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 34, 3, doi:10.1029/2006GL0028087, Feb. 2007, Peer-reviwed, Short-distance ( propagation distance less than 1,000 km) VLF subionospheric propagation is, for the first time, used to study the solar flare induced D-region perturbations of the lower ionosphere. We have used two years data for a propagation path from the Japanese VLF transmitter ( call sign JJI, frequency = 22.2 kHz, and located at Ebino, Kyushu) to a receiving station of Chofu, Tokyo. For the sake of comparison, we have also used the long distance VLF path (NWC-Chofu). First of all, the value of perturbation in amplitude (Delta A) for the short-distance path seems to be much more enhanced (Delta A = 8 similar to 9 dB) for this short-path than the long-distance paths previously studied. The experimental value of DA is found to monotonically increase with the logarithm of X-ray flux. This dependence is numerically simulated by means of the FDTD ( finite difference time domain) method to deduce the D-region perturbation, {1 + C exp {-(z - z(0))(2)/2 beta(2)} ( C: enhancement factor, z(0): reference height and beta: vertical extent) ( this modification seems to be much more realistic than the previous two parameter modeling in an exponential profile). The numerical computations with z0 similar to 60 km and beta similar to 10 km have shown that the value of Delta A increase up to similar to 6 dB in a range of X-ray flux from C = 10 to C = 10(3). As the conclusion, the Delta A is closely related with the logarithm of solar X-ray flux, so that we will be able to deduce the C value from the observed Delta A value.
Scientific journal, English - Recent progress and state of the art of seismo-electromagnetics
Katsumi Hattori; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 127, 1, 4-6, 2007, Peer-reviwed, Despite its extreme importance and years of efforts, practical short-term earthquake prediction still remains to be achieved in future. However, earthquake- related electromagnetic phenomena are recently considered as a promising candidate for short-term earthquake prediction. There have been accumulated a lot of evidences of precursory signatures in a wide frequency range (DC-VHF). In this paper, the state of the art and research progress of seismo-electromagnetics are summarized.
Scientific journal, English - Use of generalized cross validation for identification of global lightning distribution by using Schumann resonances
Yoshiaki Ando; Masashi Hayakawa
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 42, 2, doi.1029/2006RS003481, Jan. 2007, Peer-reviwed, [1] In this paper, generalized cross validation is implemented to solve an inverse problem to identify global lightning distribution from measured Schumann resonance. The inverse problem to identify the lightning distribution as a function of the distance from the observer is formulated in terms of Schumann resonance spectra calculated by the finite difference method. Tikhonov's regularization is introduced for proper inversion, and the optimal parameter for the regularization is evaluated by using the generalized cross validation as an objective estimation. We compared the results obtained in the present paper with the data collected by the Lightning Image Sensor during December 1999, and this comparison shows a better agreement than the previous results.
Scientific journal, English - A perturbation of DC electric field caused by light ion adhesion to aerosols during the growth in seismic-related atmospheric radioactivity
V. M. Sorokin; A. K. Yaschenko; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 7, 1, 155-163, 2007, Peer-reviwed, The influence of variations in conductivity and external electric current variations in the lower atmosphere on DC electric field over a seismic region is investigated. The external current is formed with the occurrence of convective upward transport of charged aerosols and their gravitational sedimentation in the atmosphere. This effect is related with the occurrence of ionization source due to seismic-related emanation of radon and other radioactive elements into the lower atmosphere. An increase in atmosphere radioactivity level results in the appearance of additional sources of ionization, and attitude dependence of the ion formation rate is calculated. Ionization source varies the atmospheric conductivity and the external current through appearance of ions with equilibrium number density and their adhesion to aerosols. We have calculated the perturbation of conductivity and external electric current as a function of altitude. Variation of conductivity and external current in the lower atmosphere leads to a perturbation of electric current which flows in the global atmosphere-ionosphere circuit. Finally, perturbations of DC electric field both on the Earth's surface and in the ionosphere are estimated.
Scientific journal, English - A possible effect of ionospheric perturbations associated with the Sumatra earthquake, as revealed from subionospheric very-low-frequency (VLF) propagation (NWC-Japan)
T. Horie; S. Maekawa; T. Yamauchi; M. Hayakawa
INTERNATIONAL JOURNAL OF REMOTE SENSING, TAYLOR & FRANCIS LTD, 28, 13-14, 3133-3139, 2007, Peer-reviwed, The observation of subionospheric very-low-frequency (VLF) propagation between the transmitter NWC (Australia) (frequency 19.8 kHz) and our three receiving sites in Japan (Chofu, Chiba, and Kochi) are used to find a possible precursor of ionospheric perturbations to the Sumatra earthquake in late December 2004. Night-time fluctuations in VLF propagation data at all three sites have exhibited significant enhancements from 4 days before the earthquake, which is likely to be a precursor to the earthquake.
Scientific journal, English - Recent studies of Schumann resonance and ELF transients
Nickolaenko, A P; M. Hayakawa
J. Atmos. Electr., 27, 1, 19-39, 2007, Peer-reviwed
Scientific journal, English - Decrease in the electric intensity of VLF/LF radio signals and possible connections
P. F. Biagi; L. Castellana; T. Maggipinto; G. Maggipinto; A. Minafra; A. Ermini; V. Capozzi; G. Perna; M. Solovieva; A. Rozhnoi; O. A. Molchanov; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 7, 3, 423-430, 2007, Peer-reviwed, In February 2002, a receiver was put into operation at the Department of Physics of Bari University (Southern Italy) to record VLF-LF radio signals. The intensity and the phase of the signals transmitted by GB (f=16 kHz, United Kingdom), FR (f=20.9 kHz, France), GE (f=23.4 kHz, Germany), IC (f=37.5 kHz, Island) and IT (f =54 kHz, Sicily, Italy) has been monitored with a 5 s sampling rate. The intensity raw data averaged over 10 min, from February 2002 to April 2006, have been analysed. Several decreases of the electric field intensity of the radio signals with a duration of some days were revealed, generally occur-ring in not concomitant periods. The GE signal decreases systematically in winter and summer each year and so, it could be supposed that such decreases are related to the transmitter. On the contrary, all the other decreases pointed out are sporadic and the previous justification does not seem realistic. On the time occurrence of these decreases, the geomagnetic activity, the meteorological conditions in the receiver area and the regional seismic activity were investigated. The main result is that, generally, a pre or post seismic effect seems to give the most convincing justification. The effect seems to appear for earthquakes with magnitude M >= 4.3, when the epicentres are within the third Fresnel zone of the radio signals or near enough to some radio path.
Scientific journal, English - The observation of ultra-low frequency emissions at Nakatsugawa, Japan, in possible association with the Sumatra, Indonesia, earthquake
K. Ohta; N. Watanabe; M. Hayakawa
INTERNATIONAL JOURNAL OF REMOTE SENSING, TAYLOR & FRANCIS LTD, 28, 13-14, 3121-3131, 2007, Peer-reviwed, The observation of direct current ( DC)/ ultra- low frequency ( ULF) electromagnetic emissions at Nakatsugawa, Gifu, Japan, has indicated that ULF emissions in the frequency below 0.1 Hz took place about 3-10 days before the disastrous Sumatra, Indonesia, earthquake. The most important support to this is based on the goniometric direction finding for those ULF emissions during the period of 17-23 December, which indicates their azimuth angle being very close to the epicentre of the earthquake. So, these ULF emissions between 17-23 December are likely to be associated with the earthquake.
Scientific journal, English - Seismo-electromagnetics as a new field of radiophysics: Electromagnetic phenomena associated with earthquakes
Hayakawa, M; O. A. Molchanov
Radio Science Bull.,, 320, 8-17, 2007, Peer-reviwed
Scientific journal, English - Seismo-electromagnetic phenomena: Recent results
M. Hayakawa
IWEMSEV-2006 (International Workshop on Electromagnetic Studies Related to Earthquakes and Volcanoes), -, -, SP-4, Nov. 2006, Peer-reviwed
International conference proceedings, English - Anomalous effect in Schumann resonance phenomena observed in Japan, possibly associated with the Chi-Chi earthquake in Taiwan
M. Hayakawa; K. Ohta; A. P. Nickolaenko
IWEMSEV-2006 (International Workshop on Electromagnetic Studies Related to Earthquakes and Volcanoes), -, -, CP-12, Nov. 2006, Peer-reviwed
International conference proceedings, English - Electromagnetic precursors to the Indonesia (Sumatra) earthqake
K. Ohta; N. Watanabe; M. Hayakawa
IWEMSEV-2006 (International Workshop on Electromagnetic Studies Related to Earthquakes and Volcanoes), -, -, CP-13, Nov. 2006, Peer-reviwed
International conference proceedings, English - On the statistical correlation between the ionosphere and seismic activities
S. Maekawa; T. Yamauchi; M. Hayakawa
IWEMSEV-2006 (International Workshop on Electromagnetic Studies Related to Earthquakes and Volcanoes), -, -, P-12, Nov. 2006, Peer-reviwed
International conference proceedings, English - Winter sprites and associated phenomena in the Hokuriku area, Japan
M. Hayakawa; T. Nakamura; Y. Matsudo; K. Yamashita; D. Iudin; T. Suzuki; K. Michimoto
28th International Conference on Lightning Protection, -, -, I-49, Sep. 2006, Peer-reviwed
International conference proceedings, English - Characteristics of ELF transients for the study of huge lightning in the world
K. Yamashita; T. Otsuyama; M. Sekiguchi; Y. Matsudo; Y. Ando; M. Hayakawa; K. Michimoto
28th International Conference on Lightning Protection, -, -, I-19, Sep. 2006, Peer-reviwed
International conference proceedings, English - Characteristics of sprites and elves associated with Japanese winter lightning, as estimated by ELF transients
Y. Matsudo; T. Suzuki; K. Yamashita; Y. Ando; M. Hayakawa; K. Michimoto
28th International Conference on Lightning Protection, -, -, I-21, Sep. 2006, Peer-reviwed
International conference proceedings, English - Measurement and estimation of charge transfer in lightning discharge using ELF transient
T. Otsuyama; M. Sekiguchi; M. Hayakawa
28th International Conference on Lightning Protection, -, -, I-35, Sep. 2006, Peer-reviwed
International conference proceedings, English - Relationship between Thunderstrom Echoes and Lightning Descharges
T. Suzuki; T. Miyazaki; M. Hayakawa; K. Michimoto; Y. Ohhigashi
28th International Conference on Lightning Protection, -, -, I-48, Sep. 2006, Peer-reviwed
International conference proceedings, English - Details of Lightning Channels Associated with Sprites in Winter around the Hokuriku Coast
T. Suzuki; Y. Matsudo; M. Hayakawa; K. MIchimoto; T. Shimura; T. Hanada
28th International Conference on Lightning Protection, -, -, I-50, Sep. 2006, Peer-reviwed
International conference proceedings, English - Evidence on a link between the intensity of Schumann resonance and global surface temperature
M. Sekiguchi; M. Hayakawa; A. P. Nickolaenko; E. Williams; Y. Hobara
28th International Conference on Lightning Protection, -, -, I-52, Sep. 2006, Peer-reviwed
International conference proceedings, English - Analysis of lower ionospheric perturbations induced by TLEs by meansof VLF Trimpi observations
Y. Matsudo; M. Hayakawa
28th International Conference on Lightning Protection, -, -, II-13, Sep. 2006, Peer-reviwed
International conference proceedings, English - The Observation of DC/ULF Emissions at Nakatsugawa, Japan in Possible Association with the Niigata-Chuetsu Earthquake
K. Ohta; N. Watanabe; M. Hayakawa
PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, 131, Aug. 2006, Peer-reviwed
International conference proceedings, English - Modelling Microwave Fixtures with the Genetic Algorithm
A. Adalev; M. Hayakawa; N. V. Korovkin; J. B. Nitsch
PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, 225, Aug. 2006, Peer-reviwed
International conference proceedings, English - Anomalous Effect in Schumann Resonance Phenomena Observed in Japan, Possibly Associated with the Earthquakes in Taiwan
M. Hayakawa; K. Ohta
PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, 136, Aug. 2006, Peer-reviwed
International conference proceedings, English - Electromagnetic Phenomena Associated with Earthquakes: Review
M. Hayakawa
PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, 130, Aug. 2006, Peer-reviwed
International conference proceedings, English - Solving Stiff Inverse Problems Using Linear Relations Between Transient Characteristics
A. Adalev; M. Hayakawa; N. V. Korovkin
PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, 315, Aug. 2006, Peer-reviwed
International conference proceedings, English - Total-Field/Scattered-Field Boundary Condition for CIP Method
Y. Ando; M. Hayakawa
PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, 429, Aug. 2006, Peer-reviwed
International conference proceedings, English - Lightning flashes conducive to the production and escape of gamma radiation to space
E. Williams; R. Boldi; J. Bor; G. Satori; C. Price; E. Greenberg; Y. Takahashi; K. Yamamoto; Y. Matsudo; Y. Hobara; M. Hayakawa; T. Chronis; E. Anagnostou; D. M. Smith; L. Lopez
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, AMER GEOPHYSICAL UNION, 111, D16, doi:10.1029/2005JD006447, Aug. 2006, Peer-reviwed, [ 1] Gamma radiation observed in space has been associated with lightning flashes in thunderstorms. These special flashes do not appear to be the large and energetic positive ground flashes that also produce sprites. Considerations of gamma ray attenuation in air indicate that such flashes may not produce gamma radiation at sufficient altitude to enable their escape to space. High-altitude intracloud lightning, most prevalent in the tropics where the tropopause is also high, may be a necessary source.
Scientific journal, English - ULF Magnetic Variations Produced by the Underground Nuclear Blasts
L. Alperovich; M. Hayakawa; G. Aburjania; A Khantadze; E. Morozov
Asia Oceania Geosciences Society 3rd Annual Meeting 2006, -, Jul. 2006
International conference proceedings, English - Anomalous Effect in Schumann Resonance Phenomena Observed in Japan, Poxxibly Associated with the Earthquakes in Taiwan
M. Hayakawa; K. Ohta; A. P. Nickolaenko
Asia Oceania Geosciences Society 3rd Annual Meeting 2006, -, Jul. 2006, Peer-reviwed
International conference proceedings, English - The Observation of DC/ULF Emission at Nakatsugawa, Japan in Possible Association with the Sumatra-Andaman Earthquake
K. Ohta; N. Watanabe; M. Hayakawa
Asia Oceania Geosciences Society 3rd Annual Meeting 2006, -, Jul. 2006, Peer-reviwed
International conference proceedings, English - Formation mechanism of the lower-ionospheric disturbances by the atmosphere electric current over a seismic region
V. M. Sorokin; A. K. Yaschenko; M. Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 68, 11, 1260-1268, Jul. 2006, Peer-reviwed, Anomalous sporadic-E layers were observed before the earthquakes. At the same time seismic activity is accompanied by the formation of an external electric current in the lower atmosphere resulting from the emanation of soil gases and transferring charged aerosols. This current is a source of conducting current perturbation in the atmosphere-ionosphere circuit. It is shown that the electric current flowing into the ionosphere from the atmosphere leads to an increase in the E-layer plasma density. The cause of plasma-density enhancement is that the atmospheric electric currents carry positive charged ions upward and the magnetospheric field-aligned electric currents carry electrons downward to the ionosphere. Furthermore, the horizontal electric field of conductive current forms a thin layer of the electron number density by drift of the long-lived metallic ions in the ionosphere. This paper presents the method for calculating the spatial distribution of electron number density perturbations in the bottom ionosphere due to the appearance of external electric current in the near-earth atmosphere. The results can be applied to the interpretation of observation data of the lower-ionospheric perturbations over seismic regions, typhoons and other catastrophes. (C) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Deembedding and unterminating microwave fixtures with the genetic algorithm
Alexei S. Adalev; Nikolay V. Korovkin; Masashi Hayakawa; Juergen B. Nitsch
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 54, 7, 3131-3140, Jul. 2006, Peer-reviwed, A new method of deembedding a test fixture effect from the data of microwave measurements is presented in this paper. It is shown that the traditional unterminating problem (the problem of finding fixture characteristics) being posed in a finite frequency range may be reduced to a problem of fitting the characteristics of the "thru" experiment. The latter is proposed to be solved by using the genetic algorithm (GA). A special trick is suggested to take fixture power loss into consideration, which is sometimes necessary to increase the goodness of fitting the characteristics. Physically correct constraints for optimization variables and optimal parameters of the GA are discussed in this paper. The method is applicable for all microwave fixtures, except for those whose characteristics are influenced by the relative position of the adapters comprising the fixture. The method does not have any specific frequency limitation and does not require any calibration standards. The results of the experiments performed have validated a high efficiency of the method proposed, and confirm that the accuracy of a deembedding problem solution is close to the goodness of fitting data of the "thru" experiment.
Scientific journal, English - ULF geomagnetic anomalous chante associated with the 2004 Sumatra-Andaman earthquakes
K. Hattori; S. Saroso; H. Ishikawa; A. Sazarachi; M. Hayakawa; J. Y. Liu; K. Shiokawa; K. Yumoto
Int'l Symp. Demeter CNES (France), -, Jun. 2006
International conference proceedings, English - Global diagustics of ions perturbations associated with seismicity using VLF transmitter signals received on Demeter satelite
O. Molchanov; A. Rozhnoi; M. Solovieva; O. Akentieva; S. Andreevsky; J. J. Berthelier; M. Parrot; P. F. Biagi; M. Hayakawa
Int'l Symp. Demeter CNES (France), -, Jun. 2006
International conference proceedings, English - Monitoring of seismo-related ionosphere perturbations using VLF signals received on the grond and satellte Demeter
A. Rozhnoi; O. A. Molchanov; M. Solovieva; V. Gladyshev; O. Akentieva; J. J. Berthelier; M. Parrot; F. Lefeuvre; P. F. Biagi; M. Hayakawa
Int'l Symp. Demeter CNES (France), -, Jun. 2006
International conference proceedings, English - ULF magnetic variations producing by the underground nuclear blasts
L. S. Alperovich; M. Hayakawa; G. D. Aburjania; A. G. Khantadze; E. Morozov
Int'l Symp. Demeter CNES (France), -, Jun. 2006
International conference proceedings, English - State-of-the Art Seismo-Electromagnetic Research
M. Hayakawa
Int'l Workshop on Seismo-Electromagnetics, -, May 2006
International conference proceedings, English - Changes in Schumann resonance records possibly related to Taiwan earthquakes
Hayakawa, M; Ohta, K; Nickolaenko, A
6th International Conference "Problems of Geocosmos", -, -, -, May 2006, Peer-reviwed
International conference proceedings, English - Ionospheric Rayleigh-Tailor instability caused by atmospheric gravity waves from sources of seismic origin
Rapoport, Yu.G; Gotynyan, O. E; Ivchenko, V. N; Hayakawa, M; Fedorenko A
6th International Conference "Problems of Geocosmos", -, -, -, May 2006, Peer-reviwed
International conference proceedings, English - Local anomalies of parameters of ULF geomagnetic perturbations before strong earthquakes
Kopytenko, Y.A; Ismagilov, V.S; Hayakawa, M
6th International Conference "Problems of Geocosmos", -, -, -, May 2006, Peer-reviwed
International conference proceedings, English - New ULF/ELF precursor origined in atmosphere: statistics and testing forecast hypothesis
Schekotov, A; Molchanov, O; Fedorov, E; Chebrov, V; Sinitsin, V; Gordeev, E; Belyaev, G; Hayakawa, M
6th International Conference "Problems of Geocosmos", -, -, -, May 2006, Peer-reviwed
International conference proceedings, English - Comparison of fractal properties of ULF emissions before the Guam earthquake of August 1993 and Japanese earthquakes of June 2000
Smirnova, N.A; Hayakawa, M
6th International Conference "Problems of Geocosmos", -, -, -, May 2006, Peer-reviwed
International conference proceedings, English - Effects of geomagnetic and seismic activity on the fractal properties of ULF emissions registered at Guam Island
Smirnova, N.A; Uritsky, V.M; Materiy I.V; Hayakawa, M
6th International Conference "Problems of Geocosmos", -, -, -, May 2006, Peer-reviwed
International conference proceedings, English - Implementation of the perfect matched layer to the CIP method
Yoshiaki Ando; Masashi Hayakawa
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E89C, 5, 645-648, May 2006, Peer-reviwed, The perfect matched layer (PML) is formulated for the use in the constrained interpolation profile (CIP) method. Numerical results are presented to examine the performance of the proposed formulation of the PML in the case of two-dimensional TM wave. The results show that the proposed methods suppress the reflection effectively in comparison with the natural absorbing boundary condition of the CIP method. We have two methods to formulate the PML, and it is shown that the both methods have equal characteristics.
Scientific journal, English - How do winter thundercloud systems generate sprite-inducing lightning in the Hokuriku area of Japan?
Tomoyuki Suzuki; Masashi Hayakawa; Yu Matsudo; Koichiro Michimoto
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 33, 10, doi: 10.1029/2005GL025433, May 2006, Peer-reviwed, Lightning and thundercloud systems leading to the generation of sprites were examined on the basis of analyses on the interrelation among radar reflectivity, lightning, and static electric field during the winter of 2004/2005 in the Hokuriku area of Japan. Eleven cases from the observed fifteen sprite events exhibit similar characteristics, so we present a typical case study of the thundercloud system. The analysis results are summarized as follows: (1) The sprite-inducing +CG was triggered by a cloud flash produced by an active cell. (2) The sprite-inducing +CG removed large positive charge from the stratiform region of another thunderstorm cell by the long linear lightning channel. (3) The origin of sprite-inducing large positive charge appears to be located in the stratiform region.
Scientific journal, English - Cellular automaton modelling of surface discharge dynamics for EMC problems
A. S. Adalev; M. Hayakawa; D. I. Iudin; N. V. Korovkin; E. E. Selina; V. Yu. Traktengerts
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 3, 10, 209-215, May 2006, Peer-reviwed, Surface charge distribution on aircraft windshields and front head shields of missiles is highly inhomogeneous and it may cause creeping discharge appearance. The discharge produces strong electromagnetic emission, which get into the bodies through apertures. A fractal model based on a cellular automaton network reproducing the dynamics of surface electrical charge distribution is proposed. The model allows us to obtain both integrated characteristics of the discharge and its local properties. The latter is of extremely importance for EMC applications.
Scientific journal, English - Mointoring of seismo-related ionospheric perturbations using VLF signal on the satellite DEMETER
Rozhnoi, A; Molchanov, O; Solovieva, M; Gladyshev, V; Akentieva, Lefeuvre, F; Biagi, P-F; Hayakawa, M
European Geosciences Union, General Assembly 2006, EGU06-A-01044, Apr. 2006
International conference proceedings, English - Seismo-atmospheric and -ionospheric perturbations
M. Hayakawa
IWEP(Int'l Workshop on Electromagnetic Precursors), 5, Mar. 2006, Peer-reviwed
International conference proceedings, English - Implementation of the PML in the CIP method
Y. Ando; M. Hayakawa
PIERS (Progress in Electromagnetics Research Symposium), 26-29, Mar. 2006, Peer-reviwed
International conference proceedings, English - Variations in global thunderstorm activity inferred from the OTD records
AP Nickolaenko; M Hayakawa; M Sekiguchi
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 33, 6, doi:10.1029/2005 GL024884, Mar. 2006, Peer-reviwed, We use the data on the planetary distribution of thunderstorms collected by optical transient detector (OTD) to derive the properties of global electric activity. Processing of optical data indicates that modern observations from space confirm the general concept of thunderstorm distribution and motion. Close similarity is demonstrated between the World Meteorological Organization data and modern records including Carnegie curve. Departures noted might be caused by thunderstorms redistribution owing to climate change; the issue deserves a special examination.
Scientific journal, English - Recent trend of electromagnetic theory in advanced technology and society
Toru Sato; Yasumitsu Miyazaki; Masashi Hayakawa; Masanori Koshiba
IEEJ Transactions on Fundamentals and Materials, 126, 1, 5-7, 2006, Peer-reviwed, Electromagnetic theory is now a universal tool used in a wide variety of leading-edge applications such as nano-technology and environmental monitoring. Under the Technical Committee on Electromagnetic Theory (EMT), three investigating committees are now running to investigate particular subjects
namely, nanometer-electromagnetic waves and X-ray fields technology, natural electromagnetic phenomena and electromagnetic theory, and computational electromagnetics. Recent trends in these fields are briefly overviewed.
Scientific journal, English - Recent studies on Schumann resonance
Yoshiaki Ando; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 126, 1, 28-30, 2006, Peer-reviwed, Recent studies on Schumann resonance, natural electromagnetic resonance in the Earth-ionosphere shell-cavity, axe summarized briefly.
Scientific journal, English - Recent progress in seismo electromagnetics (electromagnetic phenomena associated with earthquakes)
Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 126, 1, 43-44, 2006, Peer-reviwed, Recent activity has been reviewed on the seismo electromagnetics (electromagnetic phenomena assosiated with earthquakes) with respect to the possibility of short-term earthquake prediction by means of electromagnetic phenomena.
Scientific journal, English - Identification of electric circuits described by ill-conditioned mathematical models
AS Adalev; NV Korovkin; M Hayakawa
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 53, 1, 78-91, Jan. 2006, Peer-reviwed, This paper treats the problem of identification of a linear electric circuit described by an ill-conditioned mathematical model. The identification problem is considered as the problem of model parameters determination by means of processing experimental data measured for the objective circuit. Topological singularities (low-admittance cutsets and low-impedance loops) in a circuit are found to be origins of ill-conditionality of a circuit model. For more in-depth investigation the classification of electric circuits is made in respect to singularities position. It is shown that the first set of experimental data obtained for an ill-conditioned model is useless for getting the required solution of the identification problem. In this case a solution error amounts to a huge value that exponentially increases with growth in condition number of a model matrix. It is found that linear relations between model parameters can be determined in an ill-conditioned problem. Accuracy of these relations does not depend on condition number, but is defined only by measurement precision. An approach named as repeat measurements principle (RMP) and based on linear relations is suggested to solve an ill-conditioned identification problem. A new RMP-based algorithm of linear circuit identification is developed. The algorithm shows a high efficiency and allows us to determine model parameters accurate to measurement precision as applied to any type of reciprocal and nonreciprocal linear circuits.
Scientific journal, English - Surface latent heat flux and nighttime LF anomalies prior to the Mω=8.3 Tokachi-Oki earthquake
Cervone, G; S. Maekawa; R.P. Singh; M. Hayakawa; M. Kafatos; A. Shvets
Natural Hazards Earth System Sci., 6, 109-114, 2006, Peer-reviwed
Scientific journal, English - The importance of direction finding technique for the study of VLF/ELF sferics and whistlers
Masashi Hayakawa; Kenji Ohta
IEEJ Transactions on Fundamentals and Materials, 126, 2, 65-70, 2006, Peer-reviwed, The purpose of this paper is to review the previous direction finding (DP) systems including goniometer, field-analysis method and also we demonstrate how important these DF techniques are in the general studies of VLF/ELF sferics and whistlers. We have presented some latest findings such as new results on ELF transients (charge moment change) and convincing evidence on the ducted propagation of low-latitude whistlers.
Scientific journal, English - Characteristics of the sprite parent winter thundercloud with positive single flash in Hokuriku, Japan (a case study on 14th December 2001)
Tomoyuki Suzuki; Masashi Hayakawa; Yasuhide Hobara; Koichiro Michimoto; Takashi Hanada
IEEJ Transactions on Fundamentals and Materials, 126, 2, 78-83, 2006, Peer-reviwed, The sprite campaign was conducted by the sprite research group of University of Electro-Communications (UEC) during the winter of 2001/2002. On 14th December 2001, nine sprites were observed from Shimizu in Shizuoka and ELF transients were measured at Moshiri in Hokkaido. One of the sprites was also observed by the weather radar and the field mill network around the Komatsu Air Base. The sprite parent thunderclouds associated with the positive cloud-to-ground flash (+CG) were investigated with special reference to their electrical and meteorological characteristics. The results are summarized as follows
(1) The sprite parent thundercloud was very small (horizontal scale is at most 30 km) and the sprite was generated by a single flash when the thunderclouds were dissipating just after the maximum activity. (2) The sprite parent +CG occurred under the stratiform region of the thunderclouds. (3) Before the sprite causative +CG occurred, very large positive charge and negative one were found in and over the thundercloud by the analysis of sequential field mill observation.
Scientific journal, English - Ionospheric Alfvein vesonator excitation due to nearing thunderstorms
Surkov, V.V; M.Hayakawa; A.Y.Schekotov; E.N.Fedorov; O.A.Molchanov
J.Geophys.Res., 111, A01303, doi:10.1029/2005 JA011, 2006, Peer-reviwed
Scientific journal, English - Electromagnetic phenomena associated with earthquakes
Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 126, 4, 211-214, 2006, Peer-reviwed, Electromagnetic phenomena are recently found to take place prior to an earhquake, and they are regarded as the most promising candidate for short-term earthquake prediction. This report reviews the recent findings on seismo electromagnetic phenomena, including ULF emissions, seismo-atmospheric and -ionospheric perturebations, Earth's surface temperature anomaly, in-situ observational results etc.
Scientific journal, English - Multifractal analysis for the ULF geomagnetic data during the Guam earthquake
Yu-Ichi Ida; Masashi Hayakawa; Kaoru Gotoh
IEEJ Transactions on Fundamentals and Materials, 126, 4, 215-219, 2006, Peer-reviwed, In our previous papers we have shown that the fractal (monofractal) dimension (D0) showed a significant increase before the Guam earthquake occurred on August 8, 1993. In order to have a further support to this precursory effect, we have carried out the corresponding multifractal analysis (by means of detrended fluctuation analysis) for the same data to study the statistical self-similar properties in a wide range of scales. We have analyzed the ULF geomagnetic data (the most intense H component) observed at Guam observatory. As the result, we have found that we could observe significant changes in the multifractal parameters at Guam. α min showed a meaningful decrease about 25 days before the earthquake, but αmin exhibited no significant change at all, so that Δα showed a significant increase before the earthquake. Correspondingly, the generalized multifractal dimension Dq (q>
1) showed a significant decrease (whereas Dq (q<
0) showed no change) and D0 (= Dq (q=0) (as already found in our previous papers) is reconfirmed to increase before the earthquake. These multifractal characteristics seem to be a further support that these changes are closely associated with the earthquake as a precursor to the Guam earthquake.
Scientific journal, English - A statistical study on the dependence of characteristics of VLF/LF terminator times on the propagation direction
Shinko Maekawa; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 126, 4, 220-226, 2006, Peer-reviwed, We present a detailed statistical study over two years on the times of amplitude minima (so-called terminator times) observed for the VLF/LF transmitters NPM/NWC/JJY as received at three sites. We analyzed three paths: East-West long propagation path, North-South long propagation path and North-South short propagation path. In this paper we examine the statistical behavior on the dependence of VLF/LF terminator time characteristics on the propagation direction and also we focus on the short-term terminator time (TT) characteristics. We found from the data analysis that TT behavior is regularly influenced by the lower-ionospheric condition which depends on the sunrise/sunset transition and season.
Scientific journal, English - Location and electrical properties of sprite-producing lightning from a single ELF site, in “Sprites, Elves and Lightning Discharges”
Hobara, Y; M. Hayakawa; E. Williams; R. Boldi; E. Downes
Ed. by M. Fuellekrug, Springer, -, -, 211-235, 2006, Peer-reviwed
Scientific journal, English - 紀伊半島沖地震，新潟中越地震，スマトラ沖地震の前兆的現象の観測
太田健次; 石野博一; 渡邉伸夫; 早川正士
J. Atmos. Electr., 26, 1, 11-24, 2006, Peer-reviwed
Scientific journal, English - 地震電磁気現象の計測技術と研究動向
早川正士
電子情報通信学会論文誌, J89-B, 7, 1036-1045, 2006, Peer-reviwed
Scientific journal, Japanese - On the origin of stable IR anomalies detected by satellites above seismo-active regions
V. V. Surkov; O. A. Pokhotelov; M. Parrot; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 164-171, 2006, Peer-reviwed, A number of experimental evidences have recently been obtained for existence of stable anomalies of infra-red outgoing Earth radiation in seismo-active regions, basically by using NOAA-series satellite data. A theoretical model for temperature enhancement of the ground surface layer in the vicinity of fault system of the Earth's crust is developed. It is assumed that a tectonic stress in this area results in a water squeezing-out from the higher depths towards the Earth's surface. A convection mechanism of rock warming by groundwater upward filtrating is considered as a possible reason for stable temperature anomalies arising near the fault interception. According to this model the fluid filtrates upwards from the higher depth to the Earth's surface to provide an increase in the ground temperature similar to that found in observations. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Cryosphere of the earth and its influence on electromagnetic processes in seismoactive mountainous areas
Yu. B. Bashkuev; V. P. Melchinov; D. G. Buyanova; L. Kh. Angarkhaeva; M. G. Dembelov; V. B. Khaptanov; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 182-188, 2006, Peer-reviwed, The purpose of this paper is to present a detailed physical description and classification of electrical properties, construction and structure of the cryolitozone at the depth of skin-layer in VLF range for Aldan plateau, central part of the Yakutia and tundra regions not far from the Arctic Ocean. Electrical characteristics of the regions studied are typical for the cryolitozone. The frequency dispersion of some types of permafrost zones is experimentally studied. It is then shown that the frequency dispersion of the electric resistance of the layer of frozen friable sediments over the frequency from direct current to VLF-MF ranges is a peculiarity of electrical properties of the cryolitozone. A complex interpretation of the data of radioimpedance and electric soundings for permafrost rocks is carried out on the basis of developed automated numerical methods of direct and inverse problems for the radioimpedance sounding. It is determined that geoelectrical sections with the type of K (rho(1) < rho(2) > rho(3)) and the type of Q (rho(1) > rho(2) > rho(3)) are most typical for sediment rocks of the cryolitozone at the depth of 100 m of the Northern-East part of Russia. Geoelectrical section A (rho(1) < rho(2) < rho(3)) is the basic for ancient crystal rocks of the Aldan shield. Electrical properties of the cryolitozone are changed appropriately in space and in time and depend on the complex of the crystal and sediment rocks. The surface impedance shows inductive and capacitive nature and is changed in a wide range from minimum for saline lands to maximum for granitoids. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Radioprobing of underground structure of the Failure Gulf, formed as a result of the M7.5 Tsagan earthquake
Yu. B. Bashkuev; V. B. Khaptanov; M. G. Dembelov; L. Kh. Angarkhaeva; V. P. Boloev; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 210-214, 2006, Peer-reviwed, The Failure Gulf of the Baikal Lake was formed after a strong earthquake when dry land was lowered under the Baikal Lake water. Geoelectric characteristics of the seismotectonic structures of the studied region are described. Now the foundation of the gulf continues to depress. A border between modern bottom sediments and "paleo-soil" was revealed by means of method of radioimpedance sounding. Underground structure and electrophysical properties of the Failure Gulf of the Baikal Lake are defined. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Coherence of the ULF fields in the seismoactive zone of Japan
L. Alperovich; E. Morozov; M. Hayakawa; K. Hattori
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 248-257, 2006, Peer-reviwed, The work is devoted to a numerical analysis specifically adapted for multi-point detection of geomagnetic events, which precede or accompany earthquakes. Both numerically simulated data and geomagnetic perturbations during real earthquakes were investigated. The objective of this paper is to study the correlation properties of the ULF fields on small distances in seismoactive zone of Japan. By applying a combination of the Fourier, Hilbert and wavelet transforms to a single component and to their combinations we developed five correlation techniques and analyzed the geomagnetic variations at five observation points for two-year permanent observations.
Our study was in two main directions: correlation properties of the field before an earthquake, and a coherency of geomagnetic pulsations launched by the earthquake already taken place. Five different coherency criteria have been examined: (1) the cross correlation function; (2) semblance; (3) in-phase; (4) a; and (5) frequency stability criterion.
We found that the signal detection times determined by the cross correlation, semblance and in-phase criteria are much more stable compared to that found with the help of the sigma correlation technique which allows detecting when the signal to noise ratio is about similar to 3.
The study revealed anomaly signals in the period range from 15 min to 1.5 h independently at all observatories. The signature of the anomaly signal is a wave train usually consisting of 2-3 of 0.5-1 h pulses which appears 3-4 h and 8 It prior to the earthquake time if we study correlations within 90 km radius. Intensity of the signals is around 0.5-1 nT. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Restoration of seismic parameters and electrical conductivity by the diffraction tomography method
V. Troyan; M. Hayakawa; Yu. Kiselev
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 268-272, 2006, Peer-reviwed, The results of numerical simulation on restoration of the local elastic inhomogeneities and the local perturbations of electrical conductivity are considered, The restoration is implemented by the diffraction tomography method with the help of elastic and electromagnetic sounding wavefields. The perturbations of electrical conductivity are restored by "diffusive" electromagnetic field. In both cases, seismic and electromagnetic, the direct problem is solved by the finite difference method and the restoration is implemented in the time domain using the first order Born approximation. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - ULF geomagnetic perturbations due to seismic noise produced by rock fracture and crack formation treated as a stochastic process
V. V. Surkov; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 273-280, 2006, Peer-reviwed, A mechanism of ULF geomagnetic field perturbations caused by rock fracture and tectonic activity is studied. It is assumed that the rock fracture is accompanied by crack-generated seismic emission due to cracks pile up at underground cracked zones. Temporal series of seismic impulses due to the crack growth is supposed to be a stationary random process, which obeys Poisson distribution. The seismic emission of the cracks results in excitation of electric current due to motion of the conductive ground in the geomagnetic field, that is so-called diamagnetic effect in moving conductors immersed in the external magnetic field. The electric currents build up as a result of the random displacements in the conductive rock, which in turn leads to the random perturbations of the geomagnetic field. Acoustic wave field derivable from the crack seismic moment is used in order to obtain the electromagnetic variations due to growth of single crack. Averaging of these variations over random crack plane orientation and over crack sizes gives an assessment of mean level of the electromagnetic noise produced by the evolution of the crack ensemble. This assessment is consistent in magnitude with the ULF electromagnetic variations recorded prior to and after some strong earthquakes. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Singular spectral analysis and principal component analysis for signal discrimination of ULF geomagnetic data associated with 2000 Izu Island Earthquake Swarm
Katsumi Hattori; Aya Serita; Chie Yoshino; Masashi Hayakawa; Nobuhiro Isezaki
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 281-291, 2006, Peer-reviwed, In order to extract any ULF signature associated with earthquakes, the singular spectral analysis (SSA) and the principal component analysis (PCA) have been performed to investigate a possibility of discrimination of signals from different sources (geomagnetic variation, artificial noise, and the other sources (earthquake-related ULF emissions)). We apply SSA to the time series data observed at closely spaced stations; Seikoshi (SKS), Mochikoshi (MCK), and Kamo (KAM) stations. Then, PCA is applied to the time series data sets filtered at 0.01 Hz of NS component at three stations. In order to remove the most intense signal like the first principal component, we make the differential data sets of SKS-MCK and MCK-KAM for the above data. The major findings are summarized as follows. (1) It is important to apply simultaneously SSA and PCA, because SSA gives the structure of signals and the number of sensors for PCA is estimated. This makes the results more convincing. (2) There is a significant advantage using PCA with differential data sets of filtered (0.01 Hz band) signal between SKS-KAM and MCK-KAM in NS component for removing the most intense signal like global variation (solar-terrestrial interaction). This yields that the anomalous changes in the second principal component were detected more clearly, and the contribution of the second principal component is found to be 20-40%. It is enough to prove mathematical accuracy of the signal. Further application is required to accumulate events. These facts demonstrate a possibility of monitoring the crustal activity with using the SSA and PCA. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Determination of hearth position of a forthcoming strong EQ using gradients and phase velocities of ULF geomagnetic disturbances
Yu. A. Kopytenko; V. S. Ismaguilov; K. Hattori; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 292-298, 2006, Peer-reviwed, Behavior of gradient and phase velocity vectors of ULF (F < 1 Hz) geomagnetic disturbances was investigated for two earthquake (EQ) events in Japan in 2000 (M > 6) and 2003 (M = 5.8) years. The gradient and phase velocity vectors were determined using the data of three high-sensitive three-component magnetic stations situated at a distance similar to 5 km from each other (magnetic gradientometer). Two gradientometers were installed southeast and southwest of Tokyo at a distance similar to 150 km from each other. It was found that the gradient and phase velocity values had anomaly changes 3-4 months before the strong EQs. New directions of the gradient vectors took place in the same period - the directions just to the forthcoming EQ epicenter. The directions from the forthcoming EQ epicenter arouse for the phase velocity vectors. We propose to use the gradient and phase velocity vectors of the ULF geomagnetic disturbances as important factors of the short-term prediction of strong earthquakes. (c) 2006 Published by Elsevier Ltd.
Scientific journal, English - Polarization method to detect the co-seismic magnetic oscillations
A. Guglielmi; M. Hayakawa; A. Potapov; B. Tsegmed
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 299-304, 2006, Peer-reviwed, A method for detecting seismomagnetic signals is considered. These signals are generated during the course of the propagation of surface seismic Love wave from far earthquakes. Magnetic field vector of the seismomagnetic signal rotates counterclockwise and has a circular polarization, which allows us to extract the signal against the background noise. By using the described method of polarization filter the seismomagnetic signals from the earthquake on 4 June 2000 have been detected at two remote magnetic observatories. In the other case, the two signals from the disastrous tsunami 2004 earthquake were detected both for the first arrival of Love wave coming directly from the epicenter along the minor great circle arc, and for the second wave propagating along the major great circle arc. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Seismo-ionospheric depression of the ULF geomagnetic fluctuations at Kamchatka and Japan
A. Schekotov; O. Molchanov; K. Hattori; E. Fedorov; V. A. Gladyshev; G. G. Belyaev; V. Chebrov; V. Sinitsin; E. Gordeev; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 313-318, 2006, Peer-reviwed, We study preseismic behavior of the ULF geomagnetic variations at Karymshino (E158.13, N52.83), Russia, and Matsukawa (E140.94, N39.88), Japan. A depression of ULF power around local midnight is registered several days before strong isolated earthquakes. The relative depression, i.e. delta D = ((1)/(G) - ((1)/(G)))/((1)/(G)) has been analyzed, where the absolute depression is defined as a sum of inversed values of spectral power densities of horizontal components (where (1)/(G) = 1/P-hh and P-dd are the mean spectral densities of H and D components) in a sliding window +/-(10-15) days. At Karymshino, the most evident effect is found 3 days before an earthquake for the 0.5 h vicinity of local midnight in the frequency range 0.02-0.05 Hz. The data from Matsukawa are used to estimate the spatial scale of the effect and its local nature has been confirmed. Furthermore there is a definite correlation between the depression value and index of seismic activity. Thus, the analysis supports a hypothesis on seismic origin of the observed ULF geomagnetic field depression preceding an earthquake. (c) 2006 Published by Elsevier Ltd.
Scientific journal, English - Identification of earthquake sources responsible for subsurface VLF electric field emissions observed at Agra
Vikram Singh; Birbal Singh; Manoj Kumar; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 325-335, 2006, Peer-reviwed, Employing USGS earthquake data for Indian region and very low frequency (VLF, 3 kHz) subsurface electric field data obtained by using a borehole antenna at Agra in India, statistical analysis has been carried out to identify the earthquake sources responsible for VLF data. The correlation coefficient between occurrence number of VLF noise bursts and earthquakes are calculated and level of null hypothesis tested. The results show that seismic activities occurring close to the observing station and the main boundary fault located at the southern base of Himalaya are the main sources of VLF emissions recorded at the station. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Electromagnetic "seismic calm" effect in the Baikal rift zone
Yu. B. Bashkuev; I. B. Naguslaeva; Yu. P. Malyshkov; D. G. Buyanova; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 336-340, 2006, Peer-reviwed, The paper presents the results of long-term observations of the parameters of the natural impulse electromagnetic field of the Earth (NIEMFE) in the VLF range in the Baikal rift zone. The electromagnetic "seismic calm" effect has been observed, and possible reasons of changes in daily variations of magnetic components on the day before an earthquake have been analyzed. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - A study of atmospheric influence from earthquake statistics
A. Yu. Schekotov; O. A. Molchanov; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 341-345, 2006, Peer-reviwed, We analyze daily variation in earthquake (EQ) occurrence to try to find a correlation with atmospheric tide whose basic period is 24 It exactly. In selection of earthquake ensembles we use a specially developed index of seismic activity. In this way we present statistics of earthquakes in Kamchatka during the last 40 years, in Japan during the last 7 years and in California during the last 72 years, which shows a weak but recognizable effect. We explain it by tidal modulation of the earthquake instability process. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Electromagnetic precursors to the 2004 Mid Niigata Prefecture earthquake
M. Hayakawa; K. Ohta; S. Maekawa; T. Yamauchi; Y. Ida; T. Gotoh; N. Yonaiguchi; H. Sasaki; T. Nakamura
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 356-364, 2006, Peer-reviwed, This paper summarizes the electromagnetic precursory phenomena for the 2004 Mid Niigata Prefecture earthquake on October 23, 2004. Three different kinds of seismogenic perturbations have been observed; (1) lithospheric DC/ULF emissions, (2) atmospheric radio noise in the VHF band and (3) ionospheric disturbances. The DC/ULF emissions as observed at Nakatsugawa (in Gifu Prefecture) are detected on October 2-6, and the direction finding result has indicated the possible observed azimuth very close to the epicentral region. Then, we have observed the atmospheric radio noises in the VHF band on October 15-18, which are found to have the azimuth from Chofu very close to the epicentral zone. Finally, nearly at the same time (about one week before the earthquake) we have observed significant ionospheric perturbations on the subionospheric VLF/LF propagation characteristics by means of the shift in terminator time and enhancement in signal fluctuation for one particular path from the JJY (in Fukushima Prefecture) to Kochi. These perturbations not only in the lithosphere, but also in the atmosphere and ionosphere, are likely to be precursors to the 2004 Mid Niigata Prefecture earthquake. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Synthetic study of precursory phenomena of the M7.2 Hyogo-ken Nanbu earthquake
T. Ondoh; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 378-388, 2006, Peer-reviwed, Many seismic precursory phenomena in the ionosphere, atmosphere, and underground water were observed by professional and amateur people before the M7.2 Hyogo-ken Nanbu earthquake of January 17, 1995. The seismic precursory phenomena are a tornado-type seismic cloud ascending over Nojima fault near the epicenter, anomalous foEs increases above 7 MHz observed at epicentral distances within about 500 km, anomalous ELF-VLF radio noises from lightning discharges, anomalous extensions of the characteristic terminator times toward darker local times in phase variations of Omega 10.2 kHz waves passing about 70 km north of the epicenter, radon concentration increases in the atmosphere on a fault in Kobe and those in the underground water near a subsurface fault in Nishinomiya, and radon ion density increases in Okayama about 200 km west of the epicenter. We study synthetically relations among these seismic precursory phenomena in the ionosphere, atmosphere, and underground water before this earthquake onset. Then, we propose desirable observations for warning great earthquakes. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Survey of anomalous Schumann resonance phenomena observed in Japan, in possible association with earthquakes in Taiwan
Kenji Ohta; Nobuo Watanabe; Masashi Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 397-402, 2006, Peer-reviwed, The observation of ELF Schumann resonances in Nakatsugawa, Japan has suggested the presence of anomalous behavior in Schumann resonances (that is, the main point is the enhancement at the fourth (or the third) harmonic) at Nakatsugawa, and we have indicated that those anomalies in the Schumann resonances at Nakatsugawa are highly likely to be associated with the large earthquakes in Taiwan. This paper is intended to provide the statistical significance of those Schumann resonance anomalies in possible association with earthquakes in Taiwan on the basis of the ELF observation during the period from the beginning of 1999 to the end of 2004 (6 years). With the criterion of the magnitude greater than 5.0, there were observed 33 earthquakes in and around Taiwan, and the Schumann resonance anomaly is observed for 9 earthquakes (so that the anomaly percentage will be 9/29 (because no observation for 4 earthquakes)). Twenty nine earthquakes included 7 earthquakes in the land, while other 22 earthquakes took place in the sea. It is surprising that anomalous Schumann resonances are observed prior to all the land earthquakes. Two sea earthquakes from the 22, had the anomalous Schumann resonances, but these two earthquakes had the following characteristics (one was the largest magnitude, and another, the shallowest). The paper discloses the causative link between the anomalous Schumann resonances and earthquakes in Taiwan. Especially, the land earthquakes with large magnitude are found to trigger the anomalous Schumann resonances. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - LF radio anomalies revealed in Italy by the wavelet analysis: Possible preseismic effects during 1997-1998
P. F. Biagi; L. Castellana; T. Maggipinto; R. Piccolo; A. Minafra; A. Ermini; S. Martellucci; C. Bellecci; G. Perna; V. Capozzi; O. A. Molchanov; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 403-408, 2006, Peer-reviwed, Since 1996, the electric field strength of the broadcasting station CZE (Czech Republic, f = 270 kHz) has been sampled each ten minutes, by a receiver (AS) located in central Italy, 818 km far from the transmitter. Here, we present the results obtained by a detailed analysis applied on the data recorded from February 1996 up to September 2004. At first, we separated the day time data and the night time data in the radio signals; then, in the day time data we separated the data collected in winter from the data collected in summer. Finally, we applied the wavelet analysis on the previous trends. The first result was the appearance of a very clear anomaly during February-March 1998, at winter day time and at night time. This result confirms an anomaly revealed previously in the same data but analysed with a different approach. The anomaly was related to a strong (M = 5.1-6.0) seismic sequence occurred in a zone (Slovenia) lying in the middle of the transmitter-receiver path. The present result reinforces the hypothesis of the occurrence of some disturbances in the ionosphere during the preparatory phase of the Slovenia seismic sequence. The second result came from the wavelet analysis applied to the summer day time data and it was the appearance of a very clear anomaly during August-September 1997. On September 26 the Umbria-Marche (central Italy) seismic sequence started with two earthquakes with magnitude M = 5.6 and M = 5.9 and the seismic activity lasted for more than six months. We consider the August-September 1997 radio anomaly as a precursor of the previous earthquakes and a possible explanation model is proposed. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Sensitivity of LF signal to global ionosphere and atmosphere perturbations in the network of stations
A. A. Rozhnoi; M. S. Solovieva; O. A. Molchanov; M. Hayakawa; S. Maekawa; P. F. Biagi
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 409-415, 2006, Peer-reviwed, Variations of the LF signal from observations in 6 receiving stations during 2000-2004 are analyzed. Five stations are located in Japan (Kochi, Moshiri, Kasugai, Shimizu and Chiba) and one station is in Russia (Petropavlovsk-Kamchatski). All the stations are equipped with the identical OMNIPAL receivers. JJY (40 kHz) transmitter is situated in Fukushima prefecture (Japan). Sensitivity of the phase and amplitude of the LF signal to ionosphere and atmosphere perturbations associated with variations of the magnetic and meteorological conditions and solar activity is studied. Correlation of phase and amplitude variations of the LF signal with D-st-index, outer-zone particles (protons and electrons) with high-pitch angle is established for all the stations. It is found that LF anomalies are typical for the main phase of magnetic storm if the sudden commencement happens in the night time. The similarity of phase and amplitude anomalies to the structure of the simultaneously observed PO geomagnetic pulsations is found for all the stations. Correlation between variations of atmosphere pressure and amplitude of the LF signal is established. Correlation between variations of humidity for the stations located on the coast of Japan and amplitude of the LF signal is found. (c) 2006 Published by Elsevier Ltd.
Scientific journal, English - Preseismic anomaly of LF signal on the wave path Japan-Kamchatka during November-December 2004
A. A. Rozhnoi; M. S. Solovieva; O. A. Molchanov; V. Chebrov; V. Voropaev; M. Hayakawa; S. Maekawa; P. F. Biagi
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 422-427, 2006, Peer-reviwed, The variations of phase and amplitude of LF signal propagating from the transmitter JJY (40 kHz, Fukushima prefecture, Japan) are analyzed. The receiver is situated in Petropavlovsk-Kamchatski (Russia). The time interval from July1, 2004 till January 24, 2005 is included in the examination. This interval is characterized by quiet seismic conditions up to the beginning of November, but rather strong seismic activity occurs in November and December not far from Hokkaido (Japan) and in the region of northern Kuril Islands. Seismic activity in a zone of sensitivity of our wave paths is determined by three series of earthquakes with M = 5.6-7.1. Nighttime "bay-like" phase and amplitude anomalies of the LF signal begin some days before the first earthquake and continue till the last earthquake of this series (M = 6.2, November 11, 2004). Most strong and obvious anomalies appear in the amplitude of the LF signal. After that, during about one fortnight a period of seismic calm is observed. Then there is a following anomaly of the LF signal before two earthquakes (M = 7.1, 28.11.04 and M = 6.8, 6.12.04). The next LF anomaly is observed before the earthquakes on December, 18 and 21 (M = 5.8 and M = 5.6). During the whole period of seismic activity a significant shift in terminator times is also evident. The spectrum of LF seismo-induced anomalies shows a clear increase for the periods of 10-25 min. (c) 2006 Published by Elsevier Ltd.
Scientific journal, English - Seismo-electromagnetic phenomenon in terms of 3D vector problem of subionospheric radio wave propagation across the solar terminator
O. V. Soloviev; M. Hayakawa; O. A. Molchanov
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 428-436, 2006, Peer-reviwed, This paper presents a further development of mathematical model, an asymptotic theory and an appropriate numerical algorithm to study the vector VLF point source field propagation problem within the non-uniform Earth-ionosphere waveguide. It is the sequential development of our previous article [Soloviev, O.V., Hayakawa, M., Ivanov, V.I., Molchanov, O.A., 2004. Seismo-electromagnetic phenomenon in the atmosphere in terms of 3D subionospheric radio wave propagation problem. Phys. Chem. Earth 29, 639-647. doi: 10. 10 1 6/j.pce.2003.10.002]. We have taken into account 3D local anisotropic ionosphere inhomogeneity over the ground of the solar terminator transition. The local ionosphere inhomogeneity, whose centre is situated above the model earthquake, is simulated by a bell-shaped tensor impedance perturbation of the ionospheric waveguide wall. The various propagation paths, which cut across the terminator line at different angles, have been investigated. Numerical results show that the emergence of the local ionosphere inhomogeneity on the radio wave propagation across the solar terminator path deforms the curves of field amplitude and phase diurnal variations in accord with the experimental observational data. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - Modeling electrostatic-photochemistry seismoionospheric coupling in the presence of external currents
Yu. G. Rapoport; O. E. Gotynyan; V. N. Ivchenko; M. Hayakawa; V. V. Grimalsky; S. V. Koshevaya; D. Juarez-R.
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 437-446, 2006, Peer-reviwed, In this paper we propose a new 3D model for the generation of electrostatic field in the lithosphere-atmosphere-ionosphere (LAI) system by two external electric sources; namely lithospheric electric field or external current placed near the ground and (simultaneously) in the mesosphere/lower ionosphere. Then we present the results of numerical calculations. We discuss an influence of the generated electric field on the photochemical and ionospheric characteristics in the altitude range of the lower ionosphere. Appearance of strong electric field and strong change of the ionospheric characteristics (such as electron temperature and concentration) in the lower ionosphere is predicted in the presence of external electric sources in the lower atmosphere and mesosphere. An influence of the excited electric field on the losses of VLF electromagnetic waves propagating in the "Earth-ionosphere" waveguide is considered qualitatively, and rough estimation of this phenomenon is carried out. We prove a possibility of "blooming" of the ionosphere for VLF waves, if in the presence of mesospheric external current, an additional external (seismogenic) electric source appears in the lower atmosphere. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - DC electric field amplification in the mid-latitude ionosphere over seismically active faults
V. M. Sorokin; A. K. Yaschenko; V. M. Chmyrev; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 447-453, 2006, Peer-reviwed, DC electric field in the ionosphere above seismically active regions can be formed in a process of external current insertion into the atmosphere-ionosphere electric circuit. This current arises as a result of convective upward transport of charged aerosols and their gravitational sedimentation. Aerosols are injected into the atmosphere by soil gases intensified in the zones of active faults. In general the horizontal distribution of injected aerosols in such zones is asymmetric. In this report we propose a method for computation of DC electric field generated in the ionosphere and the atmosphere by external electric current with arbitrary spatial distribution. Oblique magnetic field and the conjugate ionosphere effects are taken into consideration. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - DC electric field formation in the mid-latitude ionosphere over typhoon and earthquake regions
V. M. Sorokin; A. K. Yaschenko; V. M. Chmyrev; M. Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 454-461, 2006, Peer-reviwed, The further development of electrodynamic, model of strong DC electric field formation in the ionosphere above typhoon and earthquake regions has been presented. According to this model, the external electric current works as a source of conductivity current perturbation in the atmosphere-ionosphere electric circuit. The origin of such a current is connected with upward transportation of charged water drops and aerosols in hurricane convection zone and convection of charged aerosols, which are injected in the atmosphere by elevation of soil gases in the ground of seismic region. This paper presents the method for calculation of the electric field in the atmosphere and the ionosphere generated by given distribution of external electric current in the atmosphere. Calculations of spatial distribution of DC electric field in the ionosphere were carried out with the account of oblique geomagnetic field and the conjugate ionosphere effects. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - An energy source for the mid-latitude IAR: World thunderstorm centers, nearby discharges or neutral wind fluctuations?
E. Fedorov; A. Ju. Schekotov; O. A. Molchanov; M. Hayakawa; V. V. Surkov; V. A. Gladichev
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 462-468, 2006, Peer-reviwed, Electromagnetic emissions from the world thunderstorm centers exist permanently and could be the energy source for the ionospheric Alfven resonator (IAR) oscillations. We have calculated the power spectra for two horizontal components of the magnetic field at Karimshino station far from the world thunderstorm centers at the frequencies of IAR and Schumann Resonance and we have compared them with the spectra of the registered signals in the same frequency range. The spectra calculated within the model of three world thunderstorm centers and experimental spectra agree at the frequency of the first Schumann Resonance but they disagree severely at the IAR frequency range. The calculated power spectral density at Karimshino at 1 Hz is one-two orders less than the experimental one. This fact suggests that the spectral resonance structure is not simply due to stochastic lightning discharge process of tropical thunderstorms but that some other generation mechanisms are likely to exist. (c) 2006 Published by Elsevier Ltd.
Scientific journal, English - On the earthquake effects in the regime of ionospheric Alfven resonances
A. Guglielmi; A. Potapov; B. Tsegmed; M. Hayakawa; B. Dovbnya
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 31, 4-9, 469-472, 2006, Peer-reviwed, Earthquakes can affect various parameters of the upper atmosphere above the epicenter. Ionospheric Alfven resonances are known to be very sensitive to the state of the ionospheric layers. They are observed only for magnetically quiet conditions, so that an impact from earthquakes can easily destroy the resonance structure of waves. Starting from this consideration we searched for seismic effects in the behaviour of ionospheric Alfven resonances using the data from a mid-latitude observational point. Our study revealed various examples of the ionospheric response to earthquake impacts. The results are given in the paper. (c) 2006 Elsevier Ltd. All rights reserved.
Scientific journal, English - An attempt to find precursors in the ULF geomagnetic data by means of flicker noise spectroscopy
M. Hayakawa; S. F. Timashev
NONLINEAR PROCESSES IN GEOPHYSICS, EUROPEAN GEOSCIENCES UNION, 13, 3, 255-263, 2006, Peer-reviwed, The flicker noise spectroscopy which is a new phenomenological method for the retrieval of information contained in chaotic time signals, is based on the analysis of recognizable irregularities (pulse, jumps, and discontinuities of derivatives of various order). This method is applied to the ULF (ultra-low-frequency) data observed at Guam in 1992-1994, in order to study the temporal nonlinear behavior of the lithospheric activity prior to the large 1993 Guam earthquake (8 August 1993). We have found that the lithosphere must have exhibited the step-like discontinuous behaviors in the lithosphere 101, 78, 54, 31 and 8 days before the main shock. This kind of nonlinear temporal behavior can be tracked by means of our flicker noise spectroscopy.
Scientific journal, English - Fractal analysis for the ULF data during the 1993 Guam earthquake to study prefracture criticality
Y. Ida; M. Hayakawa
NONLINEAR PROCESSES IN GEOPHYSICS, EUROPEAN GEOSCIENCES UNION, 13, 4, 409-412, 2006, Peer-reviwed, An extremely large earthquake (with magnitude of 8.2) happened on 8 August 1993 near the Guam island, and ultra-low-frequency (ULF) (frequency less than 1 Hz) electromagnetic fields were measured by 3-axis induction magnetometers at an observing station (with the epicentral distance of 65 km) with sampling frequency of I Hz. In order to study electromagnetic signature of prefracture criticality, we have undertaken the fractal (mono-fractal) analysis by means of the Higuchi's method for the ULF data during the 1993 Guam earthquake. Then, it is found that the fractal dimension exhibits five maxima 99, 75, 52, 21, and 9-4 days before the earthquake main shock, which suggests the ULF electromagnetic signature of nonlinear evolution (in the sense of self-organized criticality) taking place in the lithosphere just before the 1993 large Guam earthquake. That is, there take place step-like changes in the lithosphere during the long-term of the order of several months before the main shock.
Scientific journal, English - Global diagnostics of the ionospheric perturbations related to the seismic activity using the VLF radio signals collected on the DEMETER satellite
O. Molchanov; A. Rozhnoi; M. Solovieva; O. Akentieva; J. J. Berthelier; M. Parrot; F. Lefeuvre; P. F. Biagi; L. Castellana; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 6, 5, 745-753, 2006, Peer-reviwed, The analysis of the VLF signals radiated by ground transmitters and received on board of the French DEMETER satellite, reveals a drop of the signals (scattering spot) connected with the occurrence of large earthquakes. The extension of the "scattering spots" zone is large enough (1000-5000 km) and, probably, it increases with the magnitude of the "relative" earthquake. A possible model to explain the phenomenology, based on the acoustic gravity waves and the ionosphere turbulence, is proposed. The method of diagnostics applied to this study has the advantage to be a global one due to the world wide location of the powerful VLF transmitters and of the satellite reception. However, a specific disadvantage exists because the method requires rather a long time period of analysis due to the large longitudinal displacements among the successive satellite orbits. At the moment, at least, one month seems to be necessary.
Scientific journal, English - Multi-fractal analysis for thunderstorms leading to the generation of sprites and elves
Hayakawa, M; F. Yokose; Y. Ida; D. Iudin
J. Atmos. Electr., 26, 2, 51-57, 2006, Peer-reviwed
Scientific journal, English - Intensity of Schumann resonance oscillations and the ground surface temperature
Hayakawa, M; M. Sekiguchi; Y. Hobara; A. P. Nickolaenko
J. Atmos. Electr., 26, 2, 79-93, 2006, Peer-reviwed
Scientific journal, English - Model modifications in Schumann resonance intensity caused by a localized ionosphere disturbance over the earthquake epicenter
AP Nickolaenko; M Hayakawa; M Sekiguchi; Y Ando; K Ohta
ANNALES GEOPHYSICAE, EUROPEAN GEOSCIENCES UNION, 24, 2, 567-575, 2006, Peer-reviwed, This paper is a further extension of our latest observations and modeling by Hayakawa et al. (2005a), in which we discovered the anomalous behavior of Schumann resonance observed in Japan, in possible association with the Chi-chi earthquake in Taiwan. Schumann resonance intensity changes associated with a localized decrease in the lower ionospheric height over the earthquake epicenter are modeled. The knee model of the vertical conductivity profile of the ionosphere describes the regular Earth-ionosphere cavity, and the modified knee model is introduced for the disturbance. The localized ionosphere modification is of a Gaussian radial dependence; it has a I-Mm radius, and the decrease reaches 20 km in the lower ionosphere height over the epicenter of the earthquake (Taiwan). The diffraction problem in the Earth-ionosphere cavity with a localized disturbance is resolved by using the Stratton-Chu integral equation. This solution is constructed for the case of natural resonance oscillations driven by independent random sources distributed worldwide. The data of the Optical Transient Detector (OTD) are used to introduce the source distribution. A pronounced increase in the intensity of the Schumann resonance is obtained around the fourth mode frequency (up to 20%) when thunderstorms are concentrated in Central America. The worldwide distribution of lightning strokes blurs and slightly reduces the effect (15% increase in intensity) for the observer in Japan and the localized nonuniformity positioned over Taiwan. A clear qualitative similarity is obtained in relation to the experimental data, indicating that records collected in Japan may be explained by the impact of a localized decrease in the lower ionosphere over the epicenter of the earthquake. It is admitted that the assumed conductivity decrease could only be caused by a severe change in the ionization in the middle atmosphere. It is not in the scope of this paper to discuss the possible mechanism, but rather to show that a closer and quantitative agreement with the experiment yields information about the form and size of the ionospheric modification and about the distribution of global thunderstorm activity during measurements.
Scientific journal, English - Evidence on a link between the intensity of Schumann resonance and global surface temperature
M. Sekiguchi; M. Hayakawa; A. P. Nickolaenko; Y. Hobara
ANNALES GEOPHYSICAE, COPERNICUS PUBLICATIONS, 24, 7, 1809-1817, 2006, Peer-reviwed, A correlation is investigated between the intensity of the global electromagnetic oscillations (Schumann resonance) with the planetary surface temperature. The electromagnetic signal was monitored at Moshiri (Japan), and temperature data were taken from surface meteorological observations. The series covers the period from November 1998 to May 2002. The Schumann resonance intensity is found to vary coherently with the global ground temperature in the latitude interval from 45 degrees S to 45 degrees N: the relevant cross-correlation coefficient reaches the value of 0.9. It slightly increases when the high-latitude temperature is incorporated. Correspondence among the data decreases when we reduce the latitude interval, which indicates the important role of the middle-latitude lightning in the Schumann resonance oscillations. We apply the principal component (or singular spectral) analysis to the electromagnetic and temperature records to extract annual, semiannual, and interannual variations. The principal component analysis (PCA) clarifies the links between electromagnetic records and meteorological data.
Scientific journal, English - A statistical study on the effect of earthquakes on the ionosphere, based on the subionospheric LF propagation data in Japan
S. Maekawa; T. Horie; T. Yamauchi; T. Sawaya; M. Ishikawa; M. Hayakawa; H. Sasaki
ANNALES GEOPHYSICAE, EUROPEAN GEOSCIENCES UNION, 24, 8, 2219-2225, 2006, Peer-reviwed, A superimposed epoch analysis has been undertaken, in order to find the correlation of the ionospheric perturbations with seismic activity. We take the wave path from the Japanese LF transmitter (frequency=40 kHz) and an observing station of Kochi (wave path length of 770 km), and a much longer period (of five years) than before, is considered. This subionospheric LF propagation can be called "an integrated measurement" in the sense that any earthquakes in the LF sensitive area just around the great-circle path can influence the observed LF signals, so that we define the "effective magnitude" (Meff) by integrating the total energy from different earthquakes in the sensitive area on a current day and by converting it back into magnitude. A superimposed epoch analysis for the effective magnitude greater than 6.0 has yielded that the ionosphere is definitely disturbed in terms of both amplitude and dispersion, and that these perturbations tend to take place prior to an earthquake. The statistical z-test has also been performed, which has indicated that the amplitude is definitely depleted 2-6 days before the earthquake day and also that the dispersion is very much enhanced during the same period. This statistical study has given strong support to the existence of seismo-ionospheric perturbations for high seismic activity.
Scientific journal, English - ULF帯磁場変動データを用いた地震関連現象の抽出：レビュー
早川正士; 服部克己; 太田健次
電気学会論文誌A, 126, 12, 1238-1244, 2006, Peer-reviwed
Scientific journal, Japanese - Principal component analysis and singular spectrum analysis of ULF geomagnetic data associated with earthquakes
Hattori Katsumi; Aya Serita; Chie Yoshino; Masashi Hayakawa
URSI GA, EGH.3 (0444), Oct. 2005, Peer-reviwed
International conference proceedings, English - Anomalous effect in Shumann resonance phenomena observed in Japan, Possibly associated with the Chi-chi earthquake in Taiwan
Masashi Hayakawa; Kenji Ohta; Alexander P. Nickolaenko; Yoshiaki Ando
URSI GA, EGH.5 (0250), Oct. 2005, Peer-reviwed
International conference proceedings, English - Recent studies of Schumann resonance and ELF transients
A. P. Nickolaenko; M. Hayakawa
URSI GA, E07.1 (0262), Oct. 2005, Peer-reviwed
International conference proceedings, English - Seismo-electromagnetics
M. Hayakawa
-, Oct. 2005, Peer-reviwed
International conference proceedings, English - Seismo-electromagnetics: Review
M. Hayakawa
Int'l Worshop on Electromagnetic precursors, -, Sep. 2005, Peer-reviwed
International conference proceedings, English - Seismogenic ULF emissions
M. Hayakawa
Int'l Worshop on Earth, Ocean and Space, -, Sep. 2005, Peer-reviwed
International conference proceedings, English - Seismo Electromagnetic Phenomena
M. Hayakawa
Mini Workshop on Electromagnetic Precursors of Earthquakes: State of the Art and Research Progress, 1, Sep. 2005, Peer-reviwed
International conference proceedings, English - Strong DC electric field formation in the low latitude ionosphere over typhoons
VM Sorokin; NV Isaev; AK Yaschenko; VM Chmyrev; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 67, 14, 1269-1279, Sep. 2005, Peer-reviwed, This paper presents further development of the electrodynamic model of strong electric field formation in the ionosphere above the regions of tropical storm and typhoon origin and its comparison with new experimental results obtained from the satellite observations of DC electric field and plasma density variations over such regions. According to this model the electric field disturbance arises due to perturbation in the atmosphere-ionosphere electric circuit generated by the upward transport of charged water drops and aerosols in the hurricane convection zone. Calculations of spatial distribution of DC electric field in the ionosphere were carried out with the account of oblique geomagnetic field and the conjugate ionosphere effects. Direct measurements onboard the COSMOS-1809 satellite revealed localized DC electric field disturbances with magnitudes up to 25 mV/m and accompanying plasma density variations delta n/n similar to 6% over the zones of strong atmospheric perturbations. Comparison of observational data with the results of theoretical modeling shows that the considered model adequately describes the electrodynamic impact of meteorological processes on the ionosphere. (c) 2005 Elsevier Ltd. All rights reserved.
Scientific journal, English - Ultralow frequency (ULF) magnetic field anomalies observed at Agra and their relation to moderate seismic activities in Indian region
Kushwah, V; Singh, V; B Singh; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 67, 11, 992-1001, Jul. 2005, Peer-reviwed, A three-component search coil magnetometer (f = 0.01-30 Hz) has been employed to monitor the earthquake-induced magnetic field anomalies at Agra (Geograph. lat. 27.2 degrees N, long. 78 degrees E), India. The results show that the magnetic field amplitudes of the three components are normally low in the range of 0.03-0.7 nT, but they are occasionally enhanced to large values in the range of 0.3-5 nT (the X-component along the north-south direction being the lowest). The six month data between September, 2002 and February, 2003 have been analyzed and two cases of abnormally large amplitude enhancements are selected for detailed study. These two cases correspond to 23 November, 2002, and 5-6 February, 2003. The enhancement in amplitudes for these cases Lire examined in the light of magnetospheric micropulsations and earthquake generated Ultralow frequency (ULF) emissions. For this purpose, the amplitude variation is examined with variations of polarization parameter (Z/X) and E K, It is found that the enhancements are most probably caused by the ULF magnetic field emissions generated during moderate earthquakes (3.5 < M < 6) that Occurred in India and neighboring Pakistan successively within +/- 1 day. (c) 2005 Elsevier Ltd. All rights reserved.
Scientific journal, English - Multifractal analysis for the ULF geomagnetic data during the Guam earthquake
M. Hayakawa; Yu Ida; K. Gotoh
6th international symposium on electromagnetic compatibility and electromagnetic ecology, Section9.1.1, Jun. 2005, Peer-reviwed
International conference proceedings, English - ULF emissions associated with earthquakes
M. Hayakawa
Recent Advances in Space Technology (RAST), -, Jun. 2005, Peer-reviwed
International conference proceedings, English - Ionospheric perturbations associated with earthquakes, as studied by subionospheric VLF/LF propagation
M. Hayakawa
Recent Advances in Space Technology (RAST), -, Jun. 2005, Peer-reviwed
International conference proceedings, English - Joint ground-Demeter program using VLF transmitter signals (idea and preliminary results)
Molchanov, O. A; O. Akentieva; A. Rozhnoi; M. Solovieva; S. Andresky; M. Hayakawa; B. Biagi
DEMETER Workshop, 32, May 2005, Peer-reviwed
International conference proceedings, English - Changes in Schumann resonance records possible related to Taiwan earthquakes
Hayakawa, M; Ohta, K; Nickolaenko, A
GeoCosmos, -, May 2005, Peer-reviwed
International conference proceedings, English - Ionospheric Rayleigh-Tailor instability coused by atmospheric gravity waves from sources of seismic origin
Rapoport; Yu. G; Gotynyan, O. E; Ivchenko, V, N; Hayakawa, M; Fedorenko A
GeoCosmos, -, May 2005, Peer-reviwed
International conference proceedings, English - Comparison of fractal properties of ULF emissions before the Guam earthquake of August 1993 and Japanese earthquakes of June 2000
Smirnova, N. A; Hayakawa, M
GeoCosmos, -, May 2005, Peer-reviwed
International conference proceedings, English - Effects of geomagnetic and seismic activity on the fractal properties of ULF emissions registered at Guam Island
Smirnova, N. A; Uritsky, V. M; Materiy I. V; Hayakawa, M
GeoCosmos, -, May 2005, Peer-reviwed
International conference proceedings, English - Local anomalies of parameters of ULF geomagnetic perturbations before strong earthquakes
Kopytenko, Y. A; Ismagilov, V. S; Hayakawa, M
GeoCosmos, -, May 2005, Peer-reviwed
International conference proceedings, English - New ULF/ELF precursor origined in atmosphere: statistics and testing forecast hypothesis
Schekotov, A; Molchanov, O; Fedorov, E; Chebrov, V; Sinitsin, V; Gordeev, E; Belyaev, G; Hayakawa, M
GeoCosmos, -, May 2005, Peer-reviwed
International conference proceedings, English - Principal component analysis and singular spectrum analysis of ULF geomagnetic data associated with earthquakes
K. Hattori; A. Serita; C. Yoshino; M. Hayakawa; N. Isezaki
European Geophysical Union (EGU) General Assembly, EGU05-A-06520, Apr. 2005, Peer-reviwed
International conference proceedings, English - About possibility of earthquake forecast using short-term nonseismic events
O. Molchanov; A. Shekotov; A. Rozhnoi; M. Solovieva; E. Fedorov; M. Hayakawa
European Geophysical Union (EGU), EGU-05-A-02534, Apr. 2005, Peer-reviwed
International conference proceedings, English - Preseismic anomalies of LF signal on the radio path Japan-Kamchatka during November-December 2004
A. A. Rozhnoi; M. S. Solovieva; O. A. Molchanov; M. Hayakawa; P. F. Biagi
European Geophysical Union (EGU) General Assembly, Y056, Apr. 2005, Peer-reviwed
International conference proceedings, English - What is the Energu Source for IAR? World Thunderstorm Centers, Nearby Thunderstorms or Neutral Gas Velocity Fluctuations?
E. Fedrov; A. Schekotov; O. Molchanov; V. Surkov; M. Hayakawa; S. Andreevski
European Geophysical Union (EGU) General Assembly, Y057, Apr. 2005, Peer-reviwed
International conference proceedings, English - Preseismic ULF magnetic field depression. New results
A. Schekotov; O. Molchanov; E. Fedrov; M. Solovieva; V. Gladichev; K. Hattori; M. Hayakawa
European Geophysical Union (EGU) General Assembly, Y068, Apr. 2005, Peer-reviwed
International conference proceedings, English - Precursors of strong earthquakes in ULF magnetic disturbances
A. Schekotov; O. Molchanov; E. Fedorov; M. Solovieva; V. Gladichev; K. Hattori; M. Hayakawa
European Geophysical Union (EGU) General Assembly, Y069, Apr. 2005, Peer-reviwed
International conference proceedings, English - Excitation of the ionospheric resonance cavity by thunderstorms
VV Surkov; OA Molchanov; M Hayakawa; EN Fedorov
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 110, A4, Apr. 2005, Peer-reviwed, Excitation of the middle latitude ionospheric Alfven resonator (IAR) due to global thunderstorm activity is considered. The lightning discharges in thunderstorm centers are modeled in terms of a stochastic Poisson process. The lightning onset time and the current moment amplitude are supposed to be random values, while the shape of current moment is assumed to be a given function. Electromagnetic TM mode radiated from the lightning discharges penetrates into the ionosphere via mode coupling to the shear Alfven and magnetosonic wave modes in the E layer of the ionosphere. The ionospheric resonance cavity can trap and accumulate the shear Alfven wave energy with periods from one second to a few tenths of seconds, thereby exciting the IAR resonances. Using a simplified model of the topside ionosphere, we have analyzed a possibility for the IAR excitation far from the tropical thunderstorm region. The low-frequency power spectra of the IAR on the ground surface is studied both analytically and numerically. It is shown that the IAR power spectra exhibit spectral resonance structure (SRS) only during the nighttime conditions. Furthermore, it is found that the calculated spectra are one or two orders of magnitude lower than that observed at Karimshino station in Kamchatka region. This fact suggests that the SRS is not simply due to stochastic lightning discharge process but that some generation mechanisms for the IAR excitation at middle latitudes might also be operative.
Scientific journal, English - On the fine structure of thunderstorms leading to the generation of sprites and elves: Fractal analysis
M Hayakawa; T Nakamura; D Iudin; K Michimoto; T Suzuki; T Hanada; T Shimura
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, AMER GEOPHYSICAL UNION, 110, D6, Mar. 2005, Peer-reviwed, The fine structure of convective clouds leading to the generation of sprites and elves has been studied using radar images. Sprites and elves were observed on two days, 19 December 1998 and 27 January 1999, in lightning during winter thunderstorms on the Sea of Japan. Fractal analyses of the radar images (as an ensemble and as separate clusters) for those two days have been performed with respect to the occurrence of sprites and elves. We have found that a sprite and/or an elve is triggered when and just after the image cluster maximum size increases to a certain value (similar to 150 km) and the ensemble fractal dimension approaches a threshold (i.e., percolation threshold).
Scientific journal, English - Fractal characteristics of the natural ULF emissions in relation to geomagnetic activity
N. A. Smirnova; I. V. Yakovitskaya; M. Hayakawa; T. Itoh
IEEE 6th International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, 2005, Proceedings, 2005, 243-247, 2005, Peer-reviwed, Fractal analysis of the ULF emissions registered at low-latitude observatory Guam (Φm=9°N, ∧=225°) has been performed. Dynamics of scaling characteristics (spectral exponents β and fractal dimensions D0) has been analyzed depending on the level of geomagnetic activity and in relation to the nearby earthquake of August 8, 1993. It is found that the spectrum of ULF emissions exhibits power law behavior S(f) ∝ f-β, which is typical for fractal (self-affine) time series. It is also revealed that spectral exponent β varies in the range β = 0.7 - 2.5 in correlation with Kp-index of geomagnetic activity, and manifests a downward tendency when approaching the earthquake date. The results obtained are discussed on the basis of the SOC (self-organized criticality) approach to study the ULF emission source dynamics. © 2005 IEEE.
International conference proceedings, English - De-embedding microwave fixtures with the genetic algorithm
Alkxei S. Adalev; Nikolay V. Korovkin; Masashi Hayakawa
IEEE 6th International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, 2005, Proceedings, 2005, 190-194, 2005, Peer-reviwed, Direct measurement of frequency characteristics of a device under test (DUT) at microwave frequencies is often difficult due to some intervening fixture used for feeding the DUT. In contrast to a great number of self-calibration techniques, the method proposed in the paper does not require any calibration standard and allows us to de-embed an effect of the fixture from experimental data obtained at the Network Analyzer reference plane being based only on characteristics of the "Thru" experiment. It is shown that the traditional de-embedding problem being posed in a finite frequency range may be reduced to a problem of fitting the characteristics of the "Thru" experiment. The latter is proposed to be solved by using the genetic algorithm. A special trick is suggested to take fixture power loss into consideration, which sometimes is necessary to increase the goodness of fitting the characteristics. The results of the experiments performed have validated a high efficiency of the method proposed. © 2005 IEEE.
International conference proceedings, English - ELF帯電磁波を用いた地震前兆現象の観測
太田健次; 渡辺伸夫; 早川正士
J. Atmos. Electr., 25, 1, 11-18, 2005, Peer-reviwed
Scientific journal, Japanese - A network of reception of over-horizon VHF signals associated with earthquakes and some preliminary results
Hayakawa M; T. Gotoh; M. Ikeda
J. Atmos. Electr., 25, 1, 19-28, 2005, Peer-reviwed
Scientific journal, English - New ELF observation system at MoShiri, Japan and assessment of Acquired data
Ando Y; P. Maltsev; A. Sukhynyuk; T. Goto; T. Yamauchi; Y. Hobara; M. Sekiguchi; Y. Ikegami; M. Sera; V. Korepanov; M. Hayakawa
J. Atmos. Electr., 25, 1, 29-39, 2005, Peer-reviwed
Scientific journal, English - Enhancement of EMI Immunity of Cables using Periodical and Quasi-periodical Structures Optimized by the Genetic Algorithm
Alexei S. Adalev; Nikolai V. Korovkin; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 125, 4, 350-358, 2005, Peer-reviwed, The present work is dedicated to the problems of synthesis of stop-band structures based on non-uniform transmission lines (NTL) with parameters distributed periodically or quasi-periodically along the axial coordinate. The parameter variation is achieved by changing the structure geometry or medium properties. The subject mentioned is considered with relation to standalone filter design as well as to a problem of improving a transmission medium in such a way that this medium has properties of a stop-band filter. The problems of optimization of NTL structure are studied with the aim of obtaining maximum stop-band in the given frequency range. Based on the investigation of periodical structures the resonant conditions for different ways of parameter variation are developed. It is shown that due to changeover from the periodical structure to a quasi-periodical one it is possible in a number of cases to widen the initial stop-band obtained for the periodical structure. The genetic algorithm is used to obtain the optimal nonuniformity distribution along the line. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - A General Modeling Method of Synthesis of Complex Technical and Biological Systems
Anatoly V. Bondarenko; Masashi Hayakawa; Nikolay V. Korovkin; Ekatherina E. Selina
IEEJ Transactions on Fundamentals and Materials, 125, 7, 577-582, 2005, Peer-reviwed, A method of circuit model synthesis for an arbitrary complex technical or biological system is described. The method is based on a rather general matrix-operator representation of a system. Conditions of sufficient model synthesis are formulated as a theorem and are then proved. The theorem is concerned with linear, nonlinear, nonstationary and discretization (multiply-valued) operators. The first three types of operators permit us to build an unbalanced circuit-type model on microelectronic element basement: ARC-linear, one-port nonlinear, and one-port stationary elements. It is shown that general nodal representation of a system circuit-type model can be obtained on the basis of initial description of the original system. This way is proposed to be the most convenient for complex system modeling. Some examples of method application and comparisons with well-known algorithms are given. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Analysis on Subaerial Electric Field Radiated by a Unit Electric Current Source in the Ground
Jinping Dong; Yougang Gao; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 125, 7, 591-595, 2005, Peer-reviwed, The expressions of subaerial electric field excited by a unit electric current source in the ground, are derived using the method of image charges, and we have studied the attenuation and radiation directivity of the electric field from the current source. Lower frequency below ELF (extremely low frequency, less than 1kHz) is our interest. The main emphasis of this paper is the study on the condition and possibility for detecting seismogenic emissions for various orientations of the electric current source (from horizontal to vertical). © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Finite difference analysis of Schumann resonance and reconstruction of lightning discharge
Ando, Y; M. Hayakawa; A. V. Shvets; A. P. Nickolaenko
Radio Sci., 40, RS2002, doi:10.1029/2004RS0031, 2005, Peer-reviwed
Scientific journal, English - Simulataneous ULF/VLF amplitude anomalies observed during moderate earthquakes in India region
Singh, B; V. Kushwah; V. Singh; M. Tomar; M. Hayakawa
Indian J. Radio and Space Phys., 34, 221-232, 2005, Peer-reviwed
Scientific journal, English - DC electric field amplification in the mid-latitude ionosphere over seismically active faults
VM Sorokin; AK Yaschenko; VM Chmyrev; M Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 5, 5, 661-666, 2005, Peer-reviwed, DC electric field in the ionosphere above seismically active regions can be formed in a process of external cur-rent insertion into the atmosphere-ionosphere electric circuit. This current arises as a result of convective upward transport of charged aerosols and their gravitational sedimentation. Aerosols are injected into the atmosphere by soil gases intensified in the zones of active faults. In general case the horizontal distribution of injected aerosols in such zones is asymmetric. In this report we propose the method for computation of DC electric field generated in the ionosphere and the atmosphere by external electric current with arbitrary spatial distribution. Oblique magnetic field and the conjugate ionosphere effects are taken into consideration.
Scientific journal, English - Diurnal variations of electric activity of global thunderstorms deduced from OTD data
Hayakawa, M; M. Sekiguchi; A.P. Nickolaenko
J. Atmos. Electr., 25, 2, 55-68, 2005, Peer-reviwed
Scientific journal, English - Anomalies of LF signal during seismic activity in November-December 2004
AA Rozhnoi; MS Solovieva; OA Molchanov; M Hayakawa; S Maekawa; PF Biagi
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 5, 5, 657-660, 2005, Peer-reviwed, A signal transmitted by Japan Time Standard LF station (40 kHz, Fukushima prefecture) and recorded in Petropavlovsk-Kamchatski (Russia) is analyzed during a time interval from 1 July 2004 till 24 January 2005. This interval is characterized by quiet seismic conditions up to the beginning of November, but rather strong seismic activity occurs in November and December not far from Hokkaido (Japan) and in the region of northern Kuril Islands. There were three series of earthquakes with M=5.6-7.1 in a zone of sensitivity of our wave path during two months. Nighttime "bay-like" phase and amplitude anomalies of the LF signal are observed several days before and during every series of earthquakes. During the whole period of seismic activity a significant shift in terminator times is also evident. The spectrum of LF seismo-induced anomalies shows a clear increase for the period of about 25 min.
Scientific journal, English - Principal component analysis and singular spectrum analysis of ULF geomagnetic data associated with earthquakes
A Serita; K Hattori; C Yoshino; M Hayakawa; N Isezaki
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 5, 5, 685-689, 2005, Peer-reviwed, In order to extract any ULF signature associated with earthquakes, the principal component analysis (PCA) and singular spectral analysis (SSA) have been performed to investigate the possibility of discrimination of signals from different sources (geomagnetic variation, artificial noise, and the other sources (earthquake-related ULF emissions)). We adopt PCA to the time series data observed at closely separated stations, Seikoshi (SKS), Mochikoshi (MCK), and Kamo (KAM). In order to remove the most intense signal like the first principal component, we make the differential data sets of filtered 0.01Hz SKS-KAM and MCK-KAM in NS component and 0.01 Hz band. The major findings are as follows. (1) It is important to apply principal component analysis and singular spectral analysis simultaneously. SSA gives the structure of signals and the number of sensors for PCA is estimated. This makes the results convincing. (2) There is a significant advantage using PCA with differential data sets of filtered (0.01 Hz band) SKS-KAM and MCK-KAM in NS component for removing the most intense signal like global variation (solar-terrestrial interaction). This provides that the anomalous changes in the second principal component appeared more sharply. And the contribution of the second principal component is 20-40%. It is large enough to prove mathematical accuracy of the signal. Further application is required to accumulate events. These facts demonstrate the possibility of monitoring the crustal activity by using the PCA and SSA.
Scientific journal, English - A possible preseismic anomaly in the ground wave of a radio broadcasting (216 kHz) during July-August 1998 (Italy)
PF Biagi; L Castellana; T Maggipinto; R Piccolo; A Minafra; A Ermini; S Martellucci; C Bellecci; G Perna; Capozzi, V; OA Molchanov; M Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 5, 5, 727-732, 2005, Peer-reviwed, On February 1996, a receiver able to measure the electric field strength of LF radio broadcastings, with a sampling frequency of ten minutes, was put into operation in a site (AS) located in central Italy. One of the broadcasting stations selected is MCO (f=216 kHz), located in southeast France, 518 km far from the receiver. The MCO data collected since February 1996 up to September 2004 were examined and, at first, the night time data and the day time data (in winter and summer) were separated. Then, the wavelet analysis on the night and day time data was applied. The main result of the analysis was the appearance of a very clear anomaly during summer (July-August) 1998, at day time and at night time. The anomaly is a strong exaltation of the signal components with period in the 25-40 days range. Theoretical calculations of electric field strength were made and the only way to justify this anomaly seems to be the occurrence of an increase of the ground wave propagation mode of the radio signal. Such an increase could have been produced by an increase of the ground conductivity and by modifications of some parameter of the troposphere, mainly the refractive index. On 15 August 1998 a seismic sequence started with 17 earthquakes (M=2.2-4.6) on the Reatini mountains, a seismogenic zone located 30 km far from the AS receiver along the path MCO-AS. In this paper, the possibility that the previous radio anomaly can be a precursor of this seismic sequence is proposed.
Scientific journal, English - Subionospheric LF monitoring of ionospheric perturbations prior to the Tokachi-oki earthquake and a possible mechanism to lithosphere – ionosphere coupling
Hayakawa, M; A.V. Shvets; S. Maekawa
Adv. Polar. Upper Atmos. Res., 19, 42-54, 2005, Peer-reviwed
Scientific journal, English - The observation of ULF emissions at Nakatsugawa in possible association with the 2004 Mid Niigata Prefecture earthquake
Ohta, K; N. Watanabe; M. Hayakawa
Earth Planets Space, 57, 1003-1008, 2005, Peer-reviwed
Scientific journal, English - Does Schumann resonance affect our blood pressure?
Mitsutake, G; K. Otsuka; M. Hayakawa; G. Corné lissen; F. Halberg
Biomedicine and Pharmacotherapy, 59, 510-514, 2005, Peer-reviwed
Scientific journal, English - Near-seismic effects in ULF fields and seismo-acoustic emission: statistics and explanation
O Molchanov; A Schekotov; M Solovieva; E Fedorov; Gladyshev, V; E Gordeev; Chebrov, V; D Saltykov; Sinitsin, VI; K Hattori; M Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 5, 1, 1-10, 2005, Peer-reviwed, Preseismic intensification of fracturing has been investigated from occurrence analysis of seismo-acoustic pulses (SA foreshocks) and ULF magnetic pulses (ULF foreshocks) observed in Karimshino station in addition to seismic foreshocks. Such analysis is produced for about 40 rather strong and nearby isolated earthquakes during 2 years of recording. It is found that occurrence rate of SA foreshocks increases in the interval (-12, 0 h) before main shock with 3-times exceeding of background level in the interval (-6, -3 h), and occurrence probability of SA foreshocks (pAsimilar to75%) is higher than probability of seismic foreshocks (pssimilar to30%) in the same time interval.ULF foreshocks are masked by regular ULF activity at local morning and daytime, nevertheless we have discovered an essential ULF intensity increase in the interval (-3, +1 h) at the frequency range 0.05-0.3 Hz. Estimated occurrence probability of ULF foreshocks is about 40%. After theoretical consideration we conclude: 1) Taking into account the number rate of SA foreshocks, their amplitude and frequency range, they emit due to opening of fractures with size of L = 70-200 m (M = 1-2); 2) The electro-kinetic effect is the most promising mechanism of ULF foreshocks, but it is efficient only if two special conditions are fulfilled: a) origin of fractures near fluid-saturated places or liquid reservoirs (aquifers); b) appearance of open porosity or initiation of percolation instability; 3) Both SA and ULF magnetic field pulses are related to near-distant fractures (r <20-30 km); 4) Taking into account number rate and activation period of seismic, SA and ULF foreshocks, it is rather probable that opening of fractures and rupture of fluid reservoirs occur in the large preparation area with horizontal size about 100-200 km.
Scientific journal, English - Investigation of ULF magnetic anomaly during Izu earthquake swarm and Miyakejima volcano eruption at summer 2000, Japan
A Kotsarenko; O Molchanov; M Hayakawa; S Koshevaya; Grimalsky, V; RW Enriquez; JAL Cruz-Abeyro
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 5, 1, 63-69, 2005, Peer-reviwed, Results of the ULF electromagnetic emission during the Izu, 2000 earthquake (EQ) swarm and Miyake volcano eruptions during the summer period of 2000 are presented and analyzed. The analysis of the obtained data has been performed in 3 main directions: traditional statistical analysis, i.e. analysis of time dynamics of spectral density, polarization ratios and their derivatives, Principal Component Analysis, and Fractal Analysis. The statistical characteristics were studied at different frequency sub-bands in a frequency range 10(-3)-0.3 Hz. These methods of data processing are described and the obtained results are illustrated and discussed. Some peculiarities of the obtained results such as the rise of the second principal component and the rise of the fractal index can be interpreted as possible short-time precursors.
Scientific journal, English - Anomalous effect in Schumann resonance phenomena observed in Japan, possibly associated with the Chi-chi earthquake in Taiwan
M Hayakawa; K Ohta; AP Nickolaenko; Y Ando
ANNALES GEOPHYSICAE, EUROPEAN GEOSCIENCES UNION, 23, 4, 1335-1346, 2005, Peer-reviwed, The Schumann resonance phenomenon has been monitored at Nakatsugawa (near Nagoya) in Japan since the beginning of 1999, and due to the occurance of a severe earthquake (so-called Chi-chi earthquake) on 21 September 1999 in Taiwan we have examined our Schumann resonance data at Nakatsugawa during the entire year of 1999. We have found a very anomalous effect in the Schumann resonance, possibly associated with two large land earthquakes (one is the Chi-chi earthquake and another one on 2 November 1999 (Chic-yi earthquake) with a magnitude again greater than 6.0). Conspicuous effects are observed for the larger Chi-chi earthquake, so that we summarize the characteristics for this event. The anomaly is characterized mainly by the unusual increase in amplitude of the fourth Schumann resonance mode and a significant frequency shift of its peak frequency (similar to 1.0Hz) from the conventional value on the B-y magnetic field component which is sensitive to the waves propagating in the NS meridian plane. Anomalous Schumann resonance signals appeared from about one week to a few days before the main shock. Secondly, the goniometric estimation of the arrival angle of the anomalous signal is found to coincide with the Taiwan azimuth (the unresolved dual direction indicates toward South America). Also, the pulsed signals, such as the Q-bursts, were simultaneously observed with the "carrier" frequency around the peak frequency of the fourth Schumann resonance mode. The anomaly for the second event for the Chia-yi earthquake on 2 November had much in common. But, most likely due to a small magnitude, the anomaly appears one day before and lasts until one day after the main shock, with the enhancement at the fourth Schumann resonance mode being smaller in amplitude than the case of the Chi-chi earthquake. Yet, the other characteristics, including the goniometric direction finding result, frequency shift, etc., are nearly the same. Although the emphasis of the present study is made on experimental aspects, a possible generation mechanism for this anomaly is discussed in terms of the ELF radio wave scattered by a conducting disturbance, which is likely to take place in the middle atmosphere over Taiwan. Model computations show that the South American thunderstorms (Amazon basin) play the leading role in maintaining radio signals, leading to the anomaly in the Schumann resonance.
Scientific journal, English - Multifractal analysis for the ULF geomagnetic data during the 1993 Guam earthquake
Ida Y; M. Hayakawa; A. Adalev; K. Gotoh
Nonlinear Processes Geophys., 12, 157-162, 2005, Peer-reviwed
Scientific journal, English - Depression of the ULF geomagnetic pulsation related to ionospheric irregularities
VM Sorokin; EN Fedorov; AY Schekotov; OA Molchanov; M Hayakawa
ANNALS OF GEOPHYSICS, EDITRICE COMPOSITORI BOLOGNA, 47, 1, 191-198, Feb. 2004, We consider a depression in intensity of ULF magnetic pulsations, which is observed on the ground surface due to appearance of the irregularities in the ionosphere. It is supposed that oblique Alfven waves in the ULF frequency range are downgoing from the magnetosphere and the horizontal irregularities of ionospheric conductivity are created by upgoing atmospheric gravity waves from seismic source. Unlike the companion paper by Molchanov et al. (2003), we used a simple model of the ionospheric layer but took into consideration the lateral inhomogeneity of the perturbation region in the ionosphere. It is shown that ULF intensity could be essentially decreased for frequencies f = 0.001-0.1 Hz at nighttime but the change is negligible at daytime in coincidence with observational results.
Scientific journal, English - Natural Electromagnetic Phenomena and Electromagnetic Theory: A Review
Masashi Hayakawa; Yoshiaki Ando; Katsumi Hattori
The transactions of the Institute of Electrical Engineers of Japan.A, 124, 1, 72-79, 2004, Peer-reviwed, We review the new findings on natural electromagnetic phenomena in the near-Earth environment and will show the importance of electromagnetic analyses in elucidating the essential points of these phenomena. The topics include (1) atmospheric phenomena related to lightning (e.g. mesospheric optical emissions)
(2) seismo-electromagnetic phenomena (electromagnetic phenomena associated with earthquakes and/or volcano eruptions)
(3) plasma and wave phenomena in the Earth's ionosphere and magnetosphere
and (4) electromagnetic or electrodynamic coupling among different regions. We pay our greatest attention to the unsolved essential problems for each subject, and suggest how electromagnetics would contribute to a solution to those problems. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Numerical Aspects in the Calculation of the Transient Lightning Electromagnetic Radiation Over Lossy Ground
Akihisa Tsuji; Masashi Hayakawa
The transactions of the Institute of Electrical Engineers of Japan.A, 124, 1, 67-71, 2004, Peer-reviwed, The propagation of lightning electromagnetic radiation over a lossy ground has been investigated numerically with the combined use of a newly developed computer algorithm for Sommerfeld integrals and the fast numerical inverse Laplace transform. The transmission line model has been adopted as the lightning current model and we have dealt with lightning discharges with sharp initial peak. The dependences of the radiation fields (especially horizontal electric field) on ground conductivity, distance etc. have been extensively studied, with a special reference to its comparison with previous approximations by Zenneck and Cooray and Rubinstein. Based on these comparisons, we have found that our numerical methods are effective when calculating the radiation field from the lightning for any combinations of the parameters including ground conductivity, distance etc. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Observation of sprites over the Sea of Japan and conditions for lightning-induced sprites in winter
M Hayakawa; T Nakamura; Y Hobara; E Williams
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 109, A1, Jan. 2004, Peer-reviwed, [1] We have succeeded in observing sprites for winter lightning in the Hokuriku area ( Japan Sea side) of Japan in the winter of 2001/2002. The optical results on 3 days are compared with the corresponding characteristics of parent ( causative) lightning with particular attention to the significant differences between Hokuriku winter lightning and the more widely studied continental lightning. Despite significant differences with Hokuriku winter lightning, we have found nearly the same sprite properties as already observed in the U. S. continent with a significant difference ( simpler shape for Hokuriku winter sprite). Then, we have also discussed the criteria for sprite occurrence. Specifically, two similar criteria are found: ( 1) cloud-to-ground discharges of positive polarity and ( 2) the presence of a certain threshold in vertical charge moment ( 200 - 300 C km) ( roughly consistent with that for the U. S. continent). Mesoscale convective systems are not necessary to store the charge necessary for sprites, but the parent Hokuriku winter clouds are substantially smaller than the minimum scale for sprite occurrence in the continental lightning; however, it is larger in area than ordinary summer thunderclouds. However, there may exit another condition such as clustering or self-organizing effect of thunderclouds for sprite production.
Scientific journal, English - Characteristics of subionospheric VLF perturbation associated with winter lightning around Japan
Otsuyama T; J. Manaba; M. Hayakawa; M. Nishimura
Geophys. Res. Lett., 31, L04117, 2004, Peer-reviwed
Scientific journal, English - Nighttime amplitude decrease in 19.8kHz NWC signals observed at Agra possibly caused by moderate seismic activities along the propagation path
Singh V; B. Singh; M. Hayakawa; M. Kumar; V. Kushwah; O. P. Singh
J. Atmos. Electr., 24, 1-15, 2004, Peer-reviwed
Scientific journal, English - Alternative interpretation of ionospheric Alfven resonance
Nickolaenko A. P; S. O. Nikolayenko; Yu. Schekotov; M. Hayakawa
J. Atmos. Electr., 24, 17-30, 2004, Peer-reviwed
Scientific journal, English - TT法による地震電磁気前兆現象の検出改善
太田健次; 原俊介; 早川正士
J. Atmos. Electr., 24, 31-38, 2004, Peer-reviwed
Scientific journal, Japanese - Time domain presentation for ELF pulses with accelerated convergence
Nickolaenko A. P; L. M. Rabinowicz; M. Hayakawa
Geophys. Res. Lett., 31, L05808, 2004, Peer-reviwed
Scientific journal, English - Relation between the energy of earthquake swarm and the Hurst exponent of random variations of the geomagnetic field
M Hayakawa; K Hattori; AP Nickolaenko; LM Rabinowicz
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 379-387, 2004, Peer-reviwed, We present evidence that the Hurst exponent of the ultra low frequency component of the geomagnetic field varies similarly to the energy release of the local swarm of earthquakes observed in Japan in 2000. Similarity is demonstrated between the energy release by the shocks and variations of the Hurst exponent derived for the three component records of the geomagnetic field. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Fractal analysis of seismogenic ULF emissions
K Gotoh; M Hayakawa; NA Smirnova; K Hattori
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 419-424, 2004, Peer-reviwed, Fractal analysis has been performed on ultra-low-frequency (ULF) geomagnetic field data observed at the Izu peninsula. The first attempt of using fractal analysis for ULF geomagnetic field data during the large Guam and Biak earthquakes has been based on FFT. In order to quantitatively estimate the FFT-based fractal analysis, we first study a few fractal analyses, including the Burlaga-Klein method and the Higuchi method, as compared with the former FFT-based method. The accuracies of these three methods have been evaluated by applying them to the test data-sets of fractional Brownian motion with white noise. We conclude that the Higuchi method is superior to the FFT-based method and the Burlaga-Klein method. The S/N effect was also discussed. Then, we have applied the Higuchi method to the ULF geomagnetic field data during a big earthquake swarm (during June-August 2000) in the Izu peninsula. It is found that the fractal dimension exhibits a significant increase just before earthquakes with a magnitude Mj>6.0 associated with the Izu islands swarm with any of these three fractal analyses. This experimental finding will lend further convincing support to the presence of precursory ULF emissions. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - ULF geomagnetic anomaly associated with 2000 Izu Islands earthquake swarm, Japan
K Hattori; A Serita; K Gotoh; C Yoshino; M Harada; N Isezaki; M Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 425-435, 2004, Peer-reviwed, Electromagnetic phenomena associated with large earthquakes have been investigated to establish any method to monitor the crustal activity such as earthquakes and volcanic eruptions. The ULF geomagnetic approach is considered to be one of the most promising methods for the imminent prediction. In this paper, a new method of principal component analysis (PCA) has been applied to the ULF geomagnetic data associated with 2000 Izu Islands earthquake swarm. This swarm activity started on June 26, 2000 and terminated in September, 2000, and during this activity there were observed 5 large earthquakes whose magnitude was grater than 6 (July 1, 8, 15, 30, and August 18). During this period our ULF stations were fortunately in operation, and there are three stations closely distributed (about 5 km distances). The epicentral distances are about 80-100 km. The PCA has been applied to the ULF horizontal NS component, because we can distinguish a few noises sources based on the orthogonal decomposition in the PCA. We investigate the temporary variations of eigenvalues and eigenvectors of PCA results, and the results are summarized as follows. The first principal component is found to be the signal originated in the solar-terrestrial effects such as geomagnetic pulsation. The variation of eigenvector for the first principal component suggests that this signal is very stable over the whole analyzed period. As for the second principal component, the local artificial noise is included. As for the smallest third component in the local midnight at the Izu Peninsula, it indicated an apparent increase in the third eigenvalue a few days before the large earthquakes. Also about three months before the beginning of swarm activity, the level of the third eigenvalue was slightly enhanced. Correspondingly, the pattern of eigenvector direction in the signal subspace is changed simultaneously and it recovered to the original position after the swarm activity. These features are likely to be correlated with large earthquakes. Finally we want to emphasize that PCA approach is promising for monitoring the crustal activity. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Characteristics of ULF magnetic anomaly before earthquakes
Y Hobara; HC Koons; JL Roeder; K Yumoto; A Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 437-444, 2004, Peer-reviwed, We analyze the ULF magnetic field emissions observed at three different field sites. Large seismic events occurred near each station. Temporal dependence of the polarization ratio (ratio of horizontal to vertical magnetic field components) has been calculated in the frequency range between 1.17 mHz and 0.5 Hz with longer than 2-year data for each event. Two of three seismic events were associated with anomalous change in the polarization ratio. Remarkable similarities were found in the ratio between these two different seismic events: (1) The ratio has a significant increase about 1 month before the earthquake (about two times larger than usual level), (2) the increase is seen in the nighttime period (22-02 LT). The frequency range of increase in the ratio depends on the earthquake (0.01-0.022 Hz for the Izu Island earthquake swarms and 0.05-0.1 Hz for the Guam earthquake). Calculated ratio based on the simple theoretical model has a good agreement with observed values for these two earthquakes. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Precursory behavior of fractal characteristics of the ULF electromagnetic fields in seismic active zones before strong earthquakes
N Smirnova; M Hayakawa; K Gotoh
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 445-451, 2004, Peer-reviwed, It is now recognized that the earthquake hazard systems evolve naturally to the self-organized critical (SOC) state, in which the system is very sensitive to any external perturbations, and when the large avalanches (strong earthquakes) are probable events. Since the principal feature of the SOC state is fractal organization of the output parameters both in space (scale-invariant structure) and in time (flicker noise or 1/f noise) we can use fractal methods to investigate the evolutionary processes in the earthquake hazard system at different stages of the catastrophic event preparation. Here we apply fractal methods for extraction of earthquake precursory signatures from ULF (f = 0.001-1 Hz) geomagnetic data obtained in seismic active regions before strong earthquake events. We focus our attention on the massive Guam earthquake of August 8, 1993 (M = 8, depth = 60 km), and on a swarm of Japanese earthquakes of June-August 2000 occurred near Izu Peninsula (M > 6, depth approximate to 10 km). We analyze scaling (fractal) characteristics of ULF geomagnetic fields registered in the area less than 100 km from the earthquake epicenters, study their dynamics as approaching the earthquake dates, and compare the results obtained in both regions. Three methods have been applied to calculate scaling parameters (spectral exponents and fractal dimensions of the ULF geomagnetic time series): FFT procedure, Burlaga-Klein approach and Higuchi method. It is found that fractal characteristics of the ULF emissions manifest specific precursory behavior with some common and individual peculiarities in both seismic active areas. As the common feature, we have revealed the same increase of the ULF time series fractal dimensions (and the corresponding decrease of spectral exponents) before the both events. As the distinctive peculiarity, we have found different character of such dynamics: gradual increase (decrease) in the case of the Guam earthquakes and relatively sharp alteration in the case of the Izu earthquake swarm. For the case of Japanese earthquakes, it turned out to be possible to reveal the most effective frequency range (around f = 0.01 Hz), in which precursory behavior of fractal characteristics is more pronounced and manifested earlier than in the other frequency ranges. We give a physical interpretation of the peculiarities revealed taking into account possible specifics of the SOC processes at different depths of the earthquake focuses. (C) 2004 Published by Elsevier Ltd.
Scientific journal, English - ULF geomagnetic field measurements in Japan and some recent results associated with Iwateken Nairiku Hokubu earthquake in 1998
K Hattori; Takahashi, I; C Yoshino; N Isezaki; H Iwasaki; M Harada; K Kawabata; E Kopytenko; Y Kopytenko; P Maltsev; Korepanov, V; O Molchanov; M Hayakawa; Y Noda; T Nagao; S Uyeda
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 481-494, 2004, Peer-reviwed, Previous studies on Spitak, Loma Prieta, and Guam earthquakes indicate that large earthquakes were accompanied by preceding magnetic anomalies. In order to confirm these facts and to investigate ULF phenomena in details, a network of ULF magnetometers has been installed in Japan. Network observations including small arrays have been carried out. Also, the geomagnetic data observed at Matsukawa station associated with Iwateken Nairiku Hokubu earthquake (M6.1, September 3, 1998, depth 10 km) are presented. 4.5 years data have been analyzed and the obtained result is discussed. The variation of spectral density ratio between the horizontal and vertical components (polarization) exhibits an anomalous behavior two weeks before the earthquake. This is a unique change discovered from the rather long-term analysis, which suggests that this anomalous change might be a possible signal associated with the earthquake preparation phase. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Numerical analysis on the propagation of ULF/ELF signals in the lithosphere with highly conductive layers
AV Kulchitsky; Y Ando; M Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 495-500, 2004, Peer-reviwed, This paper deals with the numerical analyses on the effect of inhomogencities (highly conductive layers) on the propagation of seismogenic electromagnetic signals in the ULF/ELF range. For simplicity of computations we assume that the geometrical configuration is uniform in one direction, which is possibly consistent with the actual situation. We adopt the frequency domain finite difference method in the computation, and calculate the electric field at points where the fields are measurable. Our numerical results show some significant findings: (1) it is necessary to consider the presence of air region in the lithospheric propagation, (2) there exist characteristic frequencies at which we have the effective response at a point due to the presence of the conductive layer, (3) a site closest to the source does not necessarily show the strongest response, depending on the configuration of the layers. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Variations in a LF radio signal on the occasion of the recent seismic and volcanic activity in Southern Italy
PF Biagi; R Piccolo; L Castellana; A Ermini; S Martellucci; C Bellecci; Capozzi, V; G Perna; O Molchanov; M Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 551-557, 2004, Peer-reviwed, Low Frequency (LF) radio signals lie in the band 30-300 kHz. The electric field of three LF broadcasting stations-CLT (f = 189 kHz, Sicily, Italy), MCO (f = 216 kHz, France) and CZE (f = 270 kHz, Czech Republic)-has been monitored since 1997 with a sampling frequency of ten minutes at a site named AS and located in central Italy. During September-November 2002, we observed significant decreases in the electric field strength of the CLT broadcasting station. A similar effect did not appear on the MCO and CZE radio signals. On September 6 an earthquake with M = 5.6 occurred offshore, about 40 kin far from Palermo city (Sicily), starting an intense seismic crisis for more than one month. On October 27, the Etna volcano (Sicily) started an eruption that in January 2003 was still active. On October 31, an earthquake with M = 5.4 occurred at the border between Molise and Puglia regions (southern Italy) and, finally, in the period 3-6 November intense gas exhalations happened near the Eolie islands (southern Tyrrhenian sea). The CLT radio-signal decreases we observed appear clearly related to the previous activities with some possible premonitory behaviour. The LF signals are characterised by the ground-wave and the sky-wave propagation modes. The decreases in CLT radio-signal we mentioned previously are related to a reduction of the electric field strength both of the ground wave and of the sky wave. Changes in the troposphere-ground boundary zone and in the lower non-ionized atmosphere seem to be the main candidates to justify the phenomenology we observed. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Change of ionospheric plasma parameters under the influence of electric field which has lithospheric origin and due to radon emanation
Y Rapoport; Grimalsky, V; M Hayakawa; Ivchenko, V; D Juarez-R; S Koshevaya; O Gotynyan
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 579-587, 2004, Peer-reviwed, A mechanism of electric-photochemistry channel of seismo-ionospheric coupling is investigated. In particular, the penetration of electric field from the lithospheric source into the ionosphere and effect of this field on the photochemistry coefficient and ionospheric parameters in the altitude range in the lower D region are modeled numerically. It is shown that observable effects can be expected when lithospheric electric source strength is of the order of 1.5 kV/m. In this case, variations of electron temperature and electron concentration will be of the order of (40-60)% and (25-40)% respectively at the range of altitudes 60-70 km. An increase of near-ground conductivity (caused by increasing humidity and/or radon emanation) by similar to2.3 times can cause increase of electric field intensity by similar to2 times in altitude ranges of 60-70 km. Corresponding relative change of T(e) increases up to similar to50%, as compared with the case of lower near-ground temperature. Spatial shapes of relative distribution of electron temperature and the ratio of negative ion-electron concentration map the spatial shape of the lithospheric electric field distribution. Spatial shapes of electron concentration distribution and electric field strength distribution of the lithospheric source are "opposite" to each other. (C) 2004 Elsevier Ltd. All rights. reserved.
Scientific journal, English - Middle latitude LF (40 kHz) phase variations associated with earthquakes for quiet and disturbed geomagnetic conditions
A Rozhnoi; MS Solovieva; OA Molchanov; M Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 589-598, 2004, Peer-reviwed, The phase (P) and amplitude (A) anomalies in subionospheric LF signal (40 kHz) along the path Japan-Kamchatka of 2300 km have been studied for the data observed by means of a digital OminiPAL receiver for 2 years. The empirical model of background P and A daily variations for quiet and disturbed geomagnetic conditions in the absence of seismic activity is developed. We pay special attention to the P and A features during large magnetic storms. A sensitivity threshold of LF signal to deforming influence of the geomagnetic and seismic factors is defined. Two cases of bay-like behavior of LF phase and amplitude in nighttime are described as a clear earthquake precursor of LF signal. We have found from the statistical study that LF signal effect is observed only for earthquakes with M greater than or equal to 5.5 and we discuss the possible mechanisms of the effect. (C) 2004 Published by Elsevier Ltd.
Scientific journal, English - Modeling of nonlinear passage of acoustic waves caused by underground fracturing through the lithosphere
S Koshevaya; M Hayakawa; Grimalsky, V; J Siqueiros-A; R Perez-E; A Kotsarenko
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 599-605, 2004, Peer-reviwed, The nonlinear passage of the acoustic waves through the lithosphere to the surface of the Earth during earthquakes and strong underground explosions is analyzed in this report. The underlying mechanism for this is the nonlinear elastic modulus. The waves are excited at the underground source of the earthquakes. The passage of the acoustic waves propagating almost vertically upward leads to a change of the spectrum. The wide spectrum of the acoustic waves up to the radio wave range is assumed to be produced by the fracturing of the rock at the surface. This has been observed by means of satellite measurements and radio telescope investigation of meteor bombing of the Moon. If the fracture occurs at depth corresponding to high frequencies, the waves transform, through nonlinear interactions, into low and super low frequency waves. Low and super low elastic displacement waves reach the surface and produce a seismograph response. In the report the nonlinear excitation of ultra-low frequency (ULF) acoustic waves caused by low frequency (LF) seismic acoustic burst is also discussed. An analysis of the nonlinear transformation of LF acoustic waves (f similar to 100 Hz) into ULF (f less than or equal to 1 Hz) waves is presented. The LF wave is excited as the burst-like envelope of a finite transverse scale by the underground seismic motion caused seismic activity of the Earth. Then, it propagates upwards and is subject to both a nonlinear process and dissipation. The nonlinearity leads to the generation of higher harmonics and, thus, to a saw-like wave structure, and also to an increase of the ULF part of the wave spectrum. This process takes place underground at a depth of about 50-30 km. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Summary report of NASDA's earthquake remote sensing frontier project
M Hayakawa; OA Molchanov
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 617-625, 2004, Peer-reviwed, After the disastrous Kobe earthquake, the former Science and Technology Agency (STA) of Japanese Government proposed the Integrated Earthquake Frontier Project. Within the framework of this project, two institutions (RIKEN and NASDA (National Space Development Agency of Japan)) were asked to carry out over five years a feasibility study of the use of electromagnetic phenomena in short-term earthquake prediction. Since 1996 the RIKEN group has been engaged in the study of earth current and related phenomena. Meanwhile, under the NASDA project named "Earthquake Remote Sensing Frontier Project", we performed an overall study of seismo-electromagnetic phenomena occurring not only in the lithosphere, but also in the atmosphere and ionosphere. Our five-year study has yielded that the seismic effect expresses itself not only in the lithosphere (such as by ULF electromagnetic emissions, acoustic emissions etc.), but also in the atmosphere and ionosphere (by means of pre-existing transmitter signals). Most importantly, we find convincing evidence for seismo-ionospheric perturbations on the basis of subionospheric VLF/LF signals. We have established a new challenging science field, "Litho sphere-atmosphere-ionosphere coupling" or "Electromagnetics in the coupled lithosphere-atmosphere-ionosphere system". The study of this coupling would contribute to the scientific short-term earthquake prediction. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - A study of ionospheric response to regional seismic activity by VLF radio sounding
Shvets A. V; M. Hayakawa; O. A. Molchanov; Y. Ando
Phys. Chem. Earth, 29, 267-267, 2004, Peer-reviwed
Scientific journal, English - Seismo-electromagnetic phenomenon in the atmosphere in terms of 3D subionospheric radio wave propagation problem
OV Soloviev; M Hayakawa; Ivanov, VI; OA Molchanov
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 639-647, 2004, Peer-reviwed, This paper presents a mathematical model, an asymptotic theory and an appropriate numerical algorithm to study, in the scalar approximation, VLF point source field propagation problem within the non-uniform Earth-ionosphere waveguide. We have taken into account a 3D local ionospheric inhomogeneity over the ground of the solar terminator transition. The local ionospheric perturbation whose centre is situated above the model earthquake, is simulated by a bell-shaped impedance inhomogeneity of the ionospheric waveguide wall. The ionosphere model parameters are computed with allowing for the geomagnetic field. Our numerical results show that the inclusion of the local ionospheric inhomogeneity in the radio wave propagation across the solar terminator path deforms the diurnal variations of field amplitude and phase in accordance with the observational data. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English - Ionospheric Alfven resonance at middle latitudes: results of observations at Kamchatka
OA Molchanov; AY Schekotov; E Fedorov; M Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 649-655, 2004, Statistics of spectral resonance structures of the ionospheric Alfven resonances (IAR) in the ULF frequency range 0.1-5.0 Hz is presented on the basis of the analysis of data obtained from July 2000 to December 2002 (2.5 years of observations) at the Karimshino station (Kamchatka, Russia) by the conventional three component search-coil magnetometer. We analyze both the dynamic spectra of three components and polarization spectra in order to distinguish IAR. Average frequency difference DeltaF between the adjacent maxima, intensity and occurrence rate of the IAR spectra have been estimated from the averaged spectra.
The results are the following: (a) there is an evident seasonal variation in the occurrence rate with maximum at the September-January period and almost complete absence of IAR structures at the spring-early summer time; (b) occurrence maximum in the daily variation is found at 21-23 LT in autumn-winter; almost all the IAR structures are observed at local night-time; (c) averaged DeltaF is about 0.2-0.5 Hz in the autumn period but it increases up to 0.5-0.7 Hz in winter; (d) the IAR occurrence rate is in anti-correlation with the Kp index of the global magnetic activity; (e) intensity of D component exceeds essentially that of H component of the IAR structures in a majority of cases. Diurnal variations of resonance frequencies in the H and D components are not always identical.
Seasonal variation of IAR occurrence can be explained under the assumption of the existence of the ionospheric source of IAR events. We produce full-wave computations assuming the presence of an ionospheric source with k(-b) distribution on horizontal wave numbers (b similar or equal to 5/3) in correspondence with some satellite recordings. The results of the computations are found to coincide with observational IAR spectra rather well. (C) 2004 Published by Elsevier Ltd.
Scientific journal, English - Links of Schumann resonance intensity with average global land temperature
Sekiguchi M; M. Hayakawa; Y. Hobara; A. Nickolaenko; E. Williams
Radiophysics and Electronics, 9, 2, 383-391, 2004, Peer-reviwed
Scientific journal - Preseismic ULF effect and possible interpretation
Molchanov O. A; A. Yu. Schekotov; E. Fedorov; G. G. Belyaev; M. S. Solobiea; M. Hayakawa
Ann. Geophys. (Italy), 47, 1, 119-132, 2004
Scientific journal - Observation of ionospheric Alfven resonance at a middle latitude station
Hayakawa M; O. A. Molchanov; A. Y. Schekotov; E. Fedorov
Adv. Polar Upp. Atmos. Res., 18, 18, 65-76, 2004, This paper intends to report on the statistical results on the spectral resonance structures of the ionospheric Alfven resonances (IAR) in the ULF frequency range 0.1-5.0 Hz on the basis of the analysis of long-term data obtained from July 2000 to December 2002 (2.5 years) at the Karimshino station (Kamchatka, Russia) (L=2.1) by the conventional 3-component search-coil magnetometer. We analyze both the dynamic spectra of three components and polarization spectra in order to distinguish IAR from other possible noises. The average frequency difference _F between the adjacent maxima, intensity and occurrence rate of the IAR spectra have been estimated from the averaged spectra. Early papers at middle latitudes have been based on a small data base. Based on our first long-term observation at middle latitude, new findings, especially related to the seasonal variation, have emerged from this analysis. (1) There is an evident seasonal variation in the occurrence rate with a maximum in the September-January period and an almost complete absence of IAR structures in the spring-early summer time. (2) Occurrence maximum in the diurnal variation is found at 21-23 LT in the autumn and winter. Almost all the IAR structures are observed at local nighttime. (3) The averaged _F is found to be about 0.2-0.5 Hz in the autumn period but it seems to increase up to 0.5-0.7 Hz in winter. (4) The IAR occurrence rate is inversely correlated with the Kp index of global magnetic activity. (5) The intensity of D component exceeds essentially that of H component of the IAR structures in a majority of cases. Diurnal variations of resonance frequencies in the H and D components are not always identical. Finally the mechanisms to explain the observed characteristics of the IAR have been discussed.
Scientific journal, English - Characteristics of subionospheric VLF perturbations associated with winter lightning around Japan
Otsuyama T; J. Manabe; M. Hayakawa
Adv. Polar Upp. Atmos. Res., 28, 77-86, 2004
Scientific journal - Excitation of the ionospheric resonance cavity by neutral winds at middle latitudes
Surkov V. V; O.A. Pokhotelov; M. Parrot; E. N. Fedorov; M. Hayakawa
Ann. Geophysicae, 22, 2877-2899, 2004
Scientific journal - Achievements of NASDA’s Earthquake Remote Sensing Frontier Project
Hayakawa M; O. A. Molchanov; NASDA/UEC team
Terr. Atmos. Ocean. Sci., 15, 311-328, 2004
Scientific journal - VLF-LF radio signals collected at Bari (South Italy): a preliminary analysis on signal anomalies associated with earthquakes
PF Biagi; R Piccolo; L Castellana; T Maggipinto; A Ermini; S Martellucci; C Bellecci; G Perna; Capozzi, V; OA Molchanov; M Hayakawa; K Ohta
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 4, 5-6, 685-689, 2004, At the beginning of 2002 an OmniPAL receiver was put into operation at the Department of Physics of Bari University (Southern Italy). The electric field strength of five VLF-LF signals transmitted from United Kingdom (f=16kHz), France (f=20.9kHz), Germany (f=23.4kHz), Iceland (f=37.5 kHz) and Italy (f=54 kHz) has been monitoring with a 5 s sampling frequency. In a first step we reduced the amount of the data taking one datum each 10 min (mean of the 5 min raw data) and then we smoothed these data by a running adjacent averaging over 7 days. Analysing the trends we obtained, we revealed at first in the signal from the Italian transmitter two clear intensity decreases in April 2002 and in August-September 2002. At these times we observed earthquakes with M=4.3 and M=5.6 respectively near the transmitter-receiver path and a precursory effect in the previous decreases appeared. Then, we noted that all of the five radio trends in the time interval March 2002-February 2003 are more disturbed than in other periods; in particular an evident simultaneous decrease appears in January-February 2003. We propose that these disturbances are related to general excitation of the margin between the African and European plates. In a second step we examined the terminator time (evening) changes for the Italian transmitter in July-September 2002, and we found significant deviations from the mean value at the end of August, which is supportive for some precursory ionospheric signature of earthquakes.
Scientific journal, English - Lithosphere-atmosphere-ionosphere coupling as governing mechanism for preseismic short-term events in atmosphere and ionosphere
O Molchanov; E Fedorov; A Schekotov; E Gordeev; Chebrov, V; Surkov, V; A Rozhnoi; S Andreevsky; D Iudin; S Yunga; A Lutikov; M Hayakawa; PF Biagi
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 4, 5-6, 757-767, 2004, We present a general concept of mechanisms of preseismic phenomena in the atmosphere and ionosphere. After short review of observational results we conclude: 1. Upward migration of fluid substrate matter (bubble) can lead to ousting of the hot water/gas near the ground surface and cause an earthquake (EQ) itself in the strength- weakened area; 2. Thus, time and place of the bubble appearance could be random values, but EQ, geochemistry anomaly and foreshocks (seismic, SA and ULF electromagnetic ones) are casually connected; 3. Atmospheric perturbation of temperature and density could follow preseismic hot water/gas release resulting in generation of atmospheric gravity waves (AGW) with periods in a range of 6-60 min; 4. Seismoinduced AGW could lead to modification of the ionospheric turbulence and to the change of over-horizon radio-wave propagation in the atmosphere, perturbation of LF waves in the lower ionosphere and ULF emission depression at the ground.
Scientific journal, English - Results of subionospheric radio LF monitoring prior to the Tokachi (M=8, Hokkaido, 25 September 2003) earthquake
AV Shvets; M Hayakawa; S Maekawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, EUROPEAN GEOSCIENCES UNION, 4, 5-6, 647-653, 2004, Peer-reviwed, Results of simultaneous LF subionospheric monitoring over two different propagation paths prior to the very strong Tokachi earthquake (near the east coast of Hokkaido Island, 25 September 2003) of magnitude 8.3 are presented firstly. Nighttime amplitude fluctuations of the Japanese Time Standard Transmitter (JG2AS, 40 kHz) signal received at Moshiri (Japan, 142degrees E, 44degrees N) and at PetropavlovskKamchatski (Russia, 158degreesE, 53degrees N) were analyzed. As a possible precursory signature we observed synchronous intensification of quasi periodical 16-day variations of the dispersion in the signals received at both observation stations before the earthquake. The strongest deviations observed as a rule were depletions of signal amplitude probably connected with increase of loss in the ionosphere by the enhancement of turbulence. This is due to dissipation of internal gravity waves (IGW) at the lower ionosphere heights. A scheme for seismo-IGW-planetary waves (PW) interconnection has been justified to explain the observed connection with strong earthquakes. It considers the seasonal variability in the signal.
Scientific journal, English - スプライトの連続光学観測システムの構築
松戸悠; 亀田智史; 安藤芳晃; 早川正士
スプライトの連続光学観測システムの構築，高速信号処理応用技術学会誌, 7, 2, 29-42, 2004, Peer-reviwed
Scientific journal, Japanese - Ultra-Low-Frequency Electromagnetic Emissions Associated with Earthquakes
Masashi Hayakawa; Katsumi Hattori
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1101-1108, 2004, Peer-reviwed, Short-term earthquake prediction is still an urgent and important subject for seismo-active countries like Japan. There have been recently found a lot of convincing evidences on the presence of electromagnetic phenomena associated with earthquakes. One of the most promising candidates for short-term earthquake prediction is ultra-low-frequency (frequency less than 10Hz) (abbreviated as ULF) electromagnetic emission. We first review earlier observational facts, and then show our latest results, especially on the existence of such ULF emissions by means of sophisticated signal processing. Finally, we discuss the generation and propagation mechanisms of those seismo-ULF emissions. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Atmospheric Gravity Waves and their Role in the Lithosphere-troposphere-ionosphere Interaction
Georgy Lizunov; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1109-1120, 2004, Peer-reviwed, This paper is a review on the properties of atmospheric gravity waves that are responsible for the transfer of tropospheric perturbation to the ionospheric altitudes. The generation mechanism of these waves by means of meteorological sources, earthquakes and by the processes of earthquake preparation (by precursors) is examined. We suggest an experimental program for the investigation of acoustic-gravity channel of a seismic effect upon the ionosphere. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - FDTD Analysis of ELF Wave Propagation for Realistic Subionospheric Waveguide Models
Takuya Otsuyama; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1203-1209, 2004, Peer-reviwed, The space formed by the ground and ionosphere is known to act as a resonator for extremely low frequency (ELF) waves. Lightning discharges trigger this global resonance, which is known as Schumann resonance. Even though the inhomogeneity (like day-night asymmetry, local perturbation etc.) is important for such a subionospheric ELF propagation, the previous analyses have been always made by some approximations because the problem is too complicated to be analyzed by any exact full-wave analysis. This paper presents the application of the conventional numerical FDTD (finite difference time domain) method to such a subionospheric ELF wave propagation, in which any kinds of inhomogeneities can be included in this analysis. The present paper is intended to demonstrate the workability of this method for a realistic waveguide (with day-night asymmetry), by comparing the results from this method with those by the corresponding analytical method. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Natural ELF Pulses in the Time Domain: Series with Accelerated Convergence
Alexander P. Nickolaenko; L. M. Rabinowicz; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1210-1215, 2004, Peer-reviwed, We present an algorithm for accelerating the convergence of the time domain formal solution constructed for the natural electromagnetic pulses propagating in the Earth-ionosphere cavity. Such pulses originate from vertical lightning discharges and travel around the globe at extremely low frequencies (ELF). A compact formula is found for horizontal magnetic field component. Results of computations are demonstrated for a set of the source-observer distances and properties of time domain solution are discussed. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - 3D Modelling Method of VLF Subionospheric Radio Wave Propagation Allowing for a Localized Ionospheric Perturbation
O. V. Soloviev; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1216-1224, 2004, Peer-reviwed, The problem of radio wave propagation allowing for a 3D localized lower ionospheric irregularity appears in accordance with the necessity of the theoretical interpretation of VLF remote sensing data. The various processes in the Earth's crust and in the terrestial environment (earthquakes, magnetic storms, sporadic E-layers, lightning-induced electron precipitations, rocket launches, artificial ionosphere heating, nuclear explosions, etc.) may cause ionospheric perturbations with different intensity and size. This paper presents a full-wave numerical-analytical method for the 3D radio wave propagation problem. We consider the VLF field by a vertical electric dipole in the Earth-ionosphere waveguide with an irregularity in the lower ionosphere as an example. The impedance non-uniform waveguide model is constructed. In the scalar approximation, the problem is reduced to the surface integral equation for Hertz's vector component. Using an asymptotic (kr ≫ 1) integration along the transverse direction to the propagation path, we transform this equation to the one-dimensional integral equation taking into account the field scattered by the irregularity. This last one is solved by combining the semi-inversion method and the subsequent iterations. The proposed technique is useful for the study of both small- and large-scale irregularities. Numerical results of VLF point source field diffraction from a truncated highly conducting cylinder are presented. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - 2-D Finite Difference Analyses of Schumann Resonance and Identification of Lightning Distribution
Yoshiaki Ando; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1225-1231, 2004, Peer-reviwed, The extremely low frequency propagation associated with Schumann resonance phenomena are calculated numerically by the frequency-domain finite difference method, and distribution of source lightnings is identified by solving an inverse problem using the computed spectra as a set of basis functions. The finite difference equations are formulated in terms of discretized magnetic fields in the Cartesian coordinates adopting a cylindrical shell cavity for simplicity. The most reliable electron and neutral density models in the atmosphere and the ionosphere can be used to take into consideration propagation losses. The inverse problem already developed is applied to the measured data to reconstruct lightning activity distribution as a function of distance from the observation point. The reconstructed data successfully show the lightning active season, time, and distance, which are reasonable in comparison with the earlier reports. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Electromagnetic Phenomena associated with earthquakes: A frontier in terrestrial electromagnetic noise environment
M. Hayakawa
Res. Devel. Geophysics, 6, 6, 81-112, 2004, Peer-reviwed
Scientific journal, English - Is Earthquake Prediction Possible by Means of Electromagnetic Phenomena?
Masashi Hayakawa
The transactions of the Institute of Electrical Engineers of Japan.A, 124, 1, 3-4, 2004, Peer-reviwed, There have been accumulated a lot of evidences on seismo-electromagnetic phenomena, and we will show that it is not very impossible for us to make the short-term earthquake prediction by using different electromagnetic phenomena. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English - Electron acceleration by a stochastic electric field in the atmospheric layer
VY Trakhtengerts; DI Iudin; AV Kulchitsky; M Hayakawa
PHYSICS OF PLASMAS, AMER INST PHYSICS, 10, 8, 3290-3296, Aug. 2003, Peer-reviwed, Electron acceleration by a stochastic (in space) electric field is considered in the atmosphere taking into account limited scales of the acceleration layer. The general kinetic equation for the isotropic part of the electron distribution function is thereby derived, which includes runaway effects and influence of a stochastic electric field on spatial diffusion. A tail of accelerated electrons in the distribution function appears when the electric field intensity overtakes the threshold value, which is close to the threshold in a constant electric field. Stationary solutions of the kinetic equation in a finite layer are analyzed numerically in the presence of source of energetic electrons. These solutions are discussed in connection with gamma- and x-ray emissions observed inside thunderclouds. (C) 2003 American Institute of Physics.
Scientific journal, English - Phase-bunching effects in triggered VLF emissions: Antenna effect
VY Trakhtengerts; AG Demekhov; Y Hobara; M Hayakawa
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 108, A4, Apr. 2003, Peer-reviwed, [1] We consider the effect of initial phase bunching of energetic electrons on the generation of triggered ELF/VLF emissions in the magnetosphere. The electrons interacted with the primary whistler wave packet form a phase-bunched beam in the velocity space, which serves as a traveling-wave antenna emitting secondary waves. We calculate this antenna field and study its spectral and amplitude characteristics. It is shown that under the typical magnetospheric conditions, the secondary wave field is by about an order of magnitude smaller than the primary wave field. Therefore this antenna field is significant as the seed wave which is further amplified by the same beam via the cyclotron resonant mechanism. The frequency band of the antenna effect is of the order of 100 Hz near the primary-wave frequency. This is consistent with the observed frequency shift of triggered emissions.
Scientific journal, English - Penetration of an electrostatic field from the lithosphere into the ionosphere and its effect on the D-region before earthquakes
VV Grimalsky; M Hayakawa; VN Ivchenko; YG Rapoport; Zadorozhnii, VI
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 65, 4, 391-407, Mar. 2003, Peer-reviwed, The penetration of an electrostatic field, from a source located in the lithosphere into the ionosphere is investigated. The electrostatic problem is solved numerically for a medium with an inhomogeneous anisotropic conductivity coupled to an "effective upper boundary condition". The results show that the electric field in the ionosphere D-layer can effectively change the parameters of the lower ionosphere. The kinetics in the D-region are considered along with calculations of the atmospheric conductivity at an altitude of 60 km. It is concluded that (i) the atmospheric conductivity at 60 km can change by 30-70% as a result of electrostatic perturbations, created before the onset of earthquakes, and (ii) the penetration of an electrostatic field from th e lithosphere into the ionosphere above 60 km is much better at night-time than during the day. (C) 2003 Elsevier Science Ltd. All rights reserved.
Scientific journal, English - An analysis of excitation of magnetostatic surface waves in an in-plane magnetized YIG film by the integral kernel expansion method
Y Ando; N Guan; K Yashiro; S Ohkawa; M Hayakawa
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 51, 2, 492-499, Feb. 2003, Peer-reviwed, We present,a method to solve a kind of integral equations (we call it the integral kernel expansion method), and apply it to an analysis of excitation of magnetostatic surface-wave/magnetostatic backward-volume-wave modes in a magnetized yttrium-iron-garnet film. The Fourier integral of a normal component of magnetic flux density is derived in terms of an unknown current density flowing in a microstrip transducer. The integral kernel is expanded into a series of the Legendre polynomials and expansion of the unknown current density in terms of appropriate functions reduces the Fourier integral to a system of linear equations with unknown coefficients. Determination of the unknown coefficients allows us to estimate the power of magnetostatic waves, which characterizes the excitation. It is found that our numerical method is superior to the previous conventional method based on an assumed current density. In order to verify the validity of our method, we compare our results with the corresponding experiments, and we have found good agreement between the two.
Scientific journal, English - Pre-earthquake ULF electromagnetic perturbations as a result of inductive seismomagnetic phenomena during microfracturing
VV Surkov; OA Molchanov; A Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 65, 1, 31-46, Jan. 2003, Peer-reviwed, This paper proposes a generation mechanism of ULF electromagnetic noise observed several hours before some strong earthquakes. It is assumed that this effect results from the energization of crack fort-nation and fracture process in a focal zone before the main shock. Electromagnetic noise is considered as a by-product of the summation of electromagnetic micro-fields appearing in the conductive medium ahead of acoustic micro-waves radiated by an ensemble of tensile cracks. These micro-fields and currents are generated due to the movement of conductive medium in the geomagnetic field. The electromagnetic perturbations depend on the direction diagram of radiation and the attenuation of acoustic waves emitted by opening cracks. We investigate two different zones and regimes of ULF magnetic field propagation. In the near zone we expect the prevailing diffusion regime, where the sign of components of electromagnetic fields is found to be the same for all the cracks independent of their space orientation. A similar coherent effect takes place at the far or acoustic zone. These surprising effects occur, because the effective magnetic moments of current systems generated by the cracks are always directed opposite to the vector of geomagnetic field; i.e. these moments are strongly paralleled. It was established that the coherent amplification of ULF signals generated by the cracks could appear if only their size exceeds several critical values. Such an effect might appear at the background of low seismic activity because the acoustic emission of cracks is incoherent. The averaging of the fields over the ensemble of opening cracks allowed us to relate the parameters of electromagnetic noise to porosity, volumetric strain, dilatational coefficient and average size of macro-cracks at the earthquake hypocenter. Our theory predicts magnetic and electric perturbations to be of the order of 1-10 nT and 1-10 muV/m, respectively, at the distance 10-50 km from the epicenter. These values are very close to those observed prior to the occurrence of earthquakes at Loma Prieta and Spitak. (C) 2002 Published by Elsevier Science Ltd.
Scientific journal, English - the importance of direction finding technique in general VLF studies
M. Hayakawa; K. Ohta
“Very Low Frequency (VLF) Phenomena", 22-35, 2003, Peer-reviwed
Research society, English - Propagation modes of low and very low latitude whistlers
B. Singh; M. Hayakawa
“Very Low Frequency (VLF) Phenomena", 174-199, 2003, Peer-reviwed
Research society, English - Periodic Variations in the Hurst Exponent of the Geomagnetic Field
Hayakawa, M; K. Hattori; A. P. Nickolaenko; L; M. Rabinowicz
J. Atmos. Electr., 23, 1, 31-39, 2003, Peer-reviwed
Scientific journal, English - VLF electromagnrtic noise bursts observed in a borehole and their relation with low-latitude hiss
Singh, B; M. Hayakawa; P. K. Mishra; R. P. Singh; D. R. Laskshmi
J. Atmos. Solar-terr. Phys., 65, 269-276, 2003, Peer-reviwed
Scientific journal, English - Fractal analysis of the gromagnetic data obtained at Izu Peninsula, Japan in relation to the nearby earthquake swarm of June-August 2000
Gotoh; K. M. Hayakawa; N. Smirnova
Natural Hazards Earth System Sci., 3, 229-236, 2003, Peer-reviwed
Scientific journal, English - Variations of phase velocity and gradient values of ULF geomagnetic disturbances connected with the Izu strong earthquakes
V. S. Ismaguilov; Yu. A. Kopytenko; K. Hattori; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 3, 3-4, 211-215, 2003, Peer-reviwed, Results of study of anomaly behavior of amplitudes, phase velocities and gradients of ULF electromagnetic disturbances (F = 0.002-0.5 Hz) before and during a seismic active period are presented. Investigations were carried out in Japan (Izu and Chiba peninsulas) by two groups of magnetic stations spaced apart at a distance similar to 140 km. Every group (magnetic gradientometer) consists of three 3-component high sensitive magnetic stations arranged in a triangle and spaced apart at distance 4-7 km. Kakioka magnetic station (> 200 km to the North from Izu) was used as a reference point. Available data (only night-time intervals 00: 00- 07: 00 LT) were preliminary filtrated by narrow pass-band filters (16 frequency bands - periods T = 2-512 s). The amplitude, gradient and phase velocity values and probabilities of directions of gradient and phase velocity vectors were constructed for the every frequency band. Apparent resistivities of the Earth's crust in the every frequency band were calculated using the phase velocity values. It was found that Z component amplitudes of the ULF magnetic disturbances increased at Izu peninsula 2-4 weeks before the seismic active period and 2-4 days before the strongest seismic shocks (M > 6). Ratio of Z component amplitudes of Kamo (Izu) and Kakioka data (Zk/Zkk) increased during 2-4 weeks before the seismic activity start (27 June 2000) and reached a maximum just before a moment of the strongest seismic shock (EQ with M = 6.4). The gradient and the phase velocity values had an anomaly behavior during the same 2-4 weeks before the start of seismic active period. The gradient vectors of the total horizontal component of the ULF magnetic pulsations were probably directed to the regions with increased conductivity. New additional direction of the gradient vectors appeared 2-3 weeks before the seismic activity start - the direction to the seismic active area which appeared due to a magma rising.
Scientific journal, English - Fractal dynamics of electric discharges in a thundercloud
D.I. Iudin; V.Y. Trakhtegerts; M. Hayakawa
Phys. Rev. E, 68, 2003, Peer-reviwed
Scientific journal, English - Electromagnetic effect associated with regional seismic activity in Crimea during the interval July-August 2002,
Yu. A. Bogdano; I. G. Zakharov; O. F. Tyrnov; M. Hayakawa
J. Atmos. Electr., 23, 2, 57-67, 2003, Peer-reviwed
English - On the lithosphere-atmosphere coupling of seismo-electromagnetic signals
R.P. Singh; B. Singh; P. K. Mishra; M. Hayakawa
Radio Sci., 38, 4, 1065-10), 2003, Peer-reviwed
Scientific journal, English - Observations of subionospheric JG2AS Signal as precursor of the earthquakes
太田健次; 花井伸一; 原俊介; 早川正士
J. Atmos. Electr., 23, 85-95, 2003, Peer-reviwed
Scientific journal, English - Lightning discharges in association with mesospheric optical phenomena in Japan and their effect on the lower ionosphere,
Y. Hobara; M. Hayakawa; K. Ohta; H. Fukunishi
Adv. Polar Upper Atmos. Res., National Institute of Polar Research, 17, 17, 30-47, 2003, Peer-reviwed, A quantitative and statistical analysis was performed using data from coordinated measurements consisting of ELF waves, VLF subionospheric disturbances and lightning discharges associated with transient luminous events(TLEs). These TLEs(sprites and elves) were observed during winter lightning storms over the Sea of Japan in the winter of 1998/99. A clear, straightforward relationship was found between the charge moment of the parent discharge, calculated from ELF(f<15Hz) transients, and the ionospheric disturbances, with a correlation coefficient of 0.97 independent of the type of TLEs; this suggests significant atmosphere-mesosphere-ionosphere coupling and implies that a large quasi-electrostatic(QE) field change occurring above lightning discharges with TLEs plays a significant role in modifying the electrical properties of the lower ionosphere. Sprites tend to be associated with large ionospheric disturbancs(-13〜+ 4.6dB, compared with the unperturbed waves) and a large charge moment(260-875Ckm), whereas a relatively large lightning peak current(+223〜+ 470kA,)(or a slow-tail amplitude) leading to a strong electromagnetic pulse(EMP) but with a rather small ionospheric disturbances seems to be necessary to initiate elves.
Scientific journal, English - VLF signatures of ionospheric perturbation in the Hokuriku area of Japan
T.Otsuyama; T. Kariya; M. Hayakawa
Adv. Polar Upper Atmos. Res., 17, 109-119, 2003, Peer-reviwed
Scientific journal, English - Use of wavelet analysis for detection of seismogenic ULF emissions
L. Alperovich; V. Zheludev; M. Hayakawa
Radio Sci.,, 38, 6, 1093, 2003
English - FTDT analysis of ELF wave propagation and Schumann resonanace for a subionopheric waveguide model
T. Otuyama; D. Sakuma; M. Hayakawa
Radio Sci.,, 38, 6, 1103, 2003, Peer-reviwed
Scientific journal, English - Kinetics of runaway electrons in a stochastic electric field
VY Trakhtengerts; DI Iudin; AV Kulchitsky; M Hayakawa
PHYSICS OF PLASMAS, AMER INST PHYSICS, 9, 6, 2762-2766, Jun. 2002, The kinetic theory for runaway electrons in a stochastic electric field is developed. The general kinetic equation for the isotropic part of the electron distribution function is derived and is simplified to the differential form for a particular case of electric field spectral intensity. The stationary analytical solution and numerical dynamic solutions are obtained and are discussed in connection with the problem of energetic electrons in a thunderstorm cloud. (C) 2002 American Institute of Physics.
Scientific journal, English - Four-wave acousto-electromagnetic interactions in crystals with a nonlinear electrostriction
GN Burlak; SV Koshevaya; SS Mansurova; M Hayakawa
PHYSICA D-NONLINEAR PHENOMENA, ELSEVIER SCIENCE BV, 166, 3-4, 197-207, Jun. 2002, The four-wave parametric interaction of a microwave sound with a powerful electromagnetic radiation in a strong nonlinear regime is studied numerically. The interaction occurs due to account of the fourth order terms in expansion of the free energy of the anisotropic crystal. It is shown that both instability and parametric amplification of the wave amplitude in a system take place. This leads to generation of the periodical structures of short nonlinear pulses of sound. The account of small noise in a bounded crystal leads to the quasi-coherent dynamics and results in arising of self-organizing of acousto-electromagnetic waves. (C) 2002 Elsevier Science B.V. All rights reserved.
Scientific journal, English - Thermal IR satellite data application for earthquake research in Japan and China
AA Tronin; M Hayakawa; OA Molchanov
JOURNAL OF GEODYNAMICS, PERGAMON-ELSEVIER SCIENCE LTD, 33, 4-5, 519-534, May 2002, NOAA/AVHRR satellite thermal images indicated the presence of positive thermal anomalies that are associated with the large linear structures and fault systems of the Earth's crust. The relation between thermal anomalies and seismic activity was established for Middle Asia on the basis of a 7-year series of thermal images. In China the thermal anomaly has been located near Beijing, at the interface between the mountains and plain. The size of this anomaly is about 700 km in length and 50 km in width. The anomaly appeared about 6-24 days before and continued about a week after an earthquake. The anomaly was sensitive to crustal earthquakes with a magnitude more than 4.7 and for distance of up to 1000 km. The amplitude of this anomaly was about 3 degreesC. Thermal anomalies in Japan have more complex shape. The analysis of digital images for Japan shows the following: (a) the anomaly appears 7-10 days before shock; (b) the anomalies in Japan have small size; (c) probably, thermal anomaly is located in Kanto area and the magnitude of anomaly run up to 6 degreesC; (d) the tectonic position of anomalies is not clear now. (C) 2002 Elsevier Science Ltd. All rights reserved.
Scientific journal, English - Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan
S Uyeda; M Hayakawa; T Nagao; O Molchanov; K Hattori; Y Orihara; K Gotoh; Y Akinaga; H Tanaka
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, NATL ACAD SCIENCES, 99, 11, 7352-7355, May 2002, Significant anomalous changes in the ultra low frequency range (approximate to0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals.
Scientific journal, English - Acoustic emission possibly related to earthquakes, abserved at Matsumoto, Japan and its implications
A.V.Gorbatikov; O.A.Molchanov; M.Hayakawa; S.Uyeda; K.Hattori; T.Nagao.H.Tanaka; A.V.Nikoaev; P.Maltsev
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 1-10, 2002, Peer-reviwed
Research society, English - Monitoring of the ULF electromagnetic disturbances at the station station network before EQ in seimic zones of Izu and Chiba peninsulas(Japan)
Y.A,Kopytenko; V.S.Ismaguliov; K.Hattori; P.M.Voronov; M.Hayakawa; O.A.Molchanov; E.A.Kopytenko; D.B.Zaitev
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 11-18, 2002
Research society, English - ULF magnetic anomaly preceding the 1997 Kagoshima Earthquakes
K.Hattori; Y.Akinaga; M.Hayakawa; K.Yumoto; T.Nagao; S.Uyeda
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling" TERRAPUB, Terrapub, 19-28, 2002
Research society, English - Statistical analysis of the data from the ULF sensors at Seikoshi Station
H.C.Koons; J.L.Roeder; Y.Hobara; M.Hayakawa; A.C.Fraser-Smith
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling" TERRAPUB, 29-39, 2002
Research society, English - New ULF/ELF observation in Seikoshi, Izu, Japan and the precursory signal in relation with large seismic events at Izu Islands in 2000
Y.Hobara; H.C.Koons; J.L.Roeder; H.Yamaguchi; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 41-44, 2002
Research society, English - Wavelet study of long-period geomagnetic variations associated with the 1989 M=7 Roma Prieta and two 1997 M=6 Japanese earthquakes
L.S.Alperovich; V.Zheludev; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 55-60, 2002
Research society, English - Wavelet analysis and seismo-magnetic effect
Y.Lin,Q.Li; M.Hayakawa; Zeng
"Seismo Elevtromagnetics(Lithospher-Atmosphere-Ionosphere Coupling)" TERRAPUB, 61-68, 2002
Research society, English - Mexico City as seismic resonator
V.V.Grimalsky; M.Hayakawa; S.V.Koshevaya; G.N.Burlak; J.Sanchez-Mondragon
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 87-89, 2002
Research society, English - ULF emission due to inductive seismo-electromagnetic effect
O.Molchanov; A.Kulchitsky; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 153-162, 2002
Research society, English - Upward migration of earthquakes as a hint on original of foreshock activity and other related phenomena
S.Yunga; A.lutikov; O.Molchanov; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 167-172, 2002
Research society, English - Model of earthquake triggering due to gas-fluid "bubble" upward migration I. Physical rationale
D.I.Iudin; N.V.Korovkin; O.A.Molchanov; V.V.Surkov; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 177-185, 2002
Research society, English - Model of earthquake triggering due to gas-fluid "bubble" upward migration II. Finite-automation model
N.V.Korovkin; D.I.Iudin; O.A.MolchanovM.Hayakawa; V.V.Surkov
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TEERAPUB, 187-194, 2002
Research society, English - Thermofluctuational mechanism of cracks migration as a model of earthquake preparagation
V.V.Surkov; D.I.Iudin; O.A.Molchanov; N.V.Korovkin; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 195-201, 2002
Research society, English - Methods for geophysical data processing in seismic active zones
V.N.Troyan; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 215-221, 2002
Research society, English - Wavelet analysis of disturbances in subionospheric VLF propagation correlated with earthquakes
M.Hayakawa; O.A.Molchanov; N.Shima; A.V.Shvets; N.Yamamoto
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 223-228, 2002
Research society, English - The role of gravity waves in the lithosphere-ionosphere coupling, as revealed from the subionospheric LF propagation data
K.Miyaki; M.Hayakawa; O.A.Molchanov
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 229-232, 2002
Research society, English - Relationship between ELF magnetic fields and Taiwan earthquake
K.Ohta,K.Umeda; N.Watanabe; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 233-237, 2002
Research society, English - Possible premonitory behaviour of LF radiowaves on the occasion of the Slovenia earthquakes (M=5.2-6.0-5.1) occurred on March-May 1998
P.F.Biagi; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 249-253, 2002
Research society, English - Reception of over-horizon FM signals associated with earthquakes
Y.Fukumoto; M.Hayakawa; H.Yasuda
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionospher Coupling)" TERRAPUB, 263-266, 2002
Research society, English - Possible influence of seismicity by gravity waves on ionospheric equatrial anomaly from data of IK-24 satellite 1. Search for idea of seismo-ionosphere coupling
O.A.Molchanov; M.Hayakawa; V.V.Afonin; O.A.Akentieva; E.A.Mareev
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 275-285, 2002
Research society, English - Possible influence of seismicity by gravity waves on ionospheric equatrial anomaly from data of IK-24 satellite 2. Equatorial anomaly and small-scale ionopheric turbulence
O.A.Molchanov; M.Hayakawa; V.V.Afronin; O.A.Akentieva; E.A.Mareev; V.Y.Trakhtengerts
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 287-296, 2002
Research society, English - Comparison of simulataneous variations of the ionospheric total electron conten and geomagnetic field associated with strong earthquakes
Sh.Naman; L.S.Alperovich; Sh.Wdowinski; M.Hayakawa; E.Calais
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 303-308, 2002
Research society, English - Model variation in atmoapheric radio noise caused by pre-seismic modifications of tropospheric conductivity profile
M.Hayakawa; O.A.Molchanov; A.P.Nicolaenko
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 349-352, 2002
Research society, English - Seismo discharge model of anomalous sporadic E ionization before great earthquakes
T.Ondoh; M.Hayakawa
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 385-390, 2002
Research society, English - Coordinated registration of seismogenic effects in the ionosphere by means of remote ground-based and local satellite measurements
V.Korepanov; O.Molchanov; M.Hayakawa; G.Lizunov
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling" TERRAPUB, 397-403, 2002
Research society, English - Russian-Japanese complex geophysical observatory in Kamchatka for monitoring of phenomena connected with seismic activity
S.Uyeda,T.Nagao; K.Hattori; Y.Noda; M.Hayakawa; K.Miyaki; O.Molvhanov; V.Gladychev; L.Baransky; A.Schekotov; G.Belyaev; E.Fedorov; O.Pokhotelov; S.Andreevsky; A.Rozhnoi,Y.Kh
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 413-419, 2002
Research society, English - Some preliminary results of seismo-electromagnetic research at Complex geophysical observatory, Kamchatka
V.Gladychev; L.Baransky; A.Schekotov; E.Fedorov; O.Pokhotelov; S.Andreevsky; A.Rozhnoi; Y.Khabazin; G.Belyaev; A.Gorbatikov; E.Gordeev; V.Chebrov; V.Sinitsin; A.Lutikov,S.Yu
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 421-432, 2002
Research society, English - Infrastructural analysis of geomagnetic field and earthquake prediction
X.Zeng,M.Hayakawa; Y.F.Lin; C.R.Xu
"Seismo Electromagnetics(Lithosphere-Atmosphere-Ionosphere Coupling)" TERRAPUB, 463-468, 2002
Research society, English - FDTD simulation and expermental result on VLF scattering by ionospheric perturbations in Earth-ionosphere waveguide
T.Otsuyama; M.Hayakawa
Trans. IEE of Japan, 122-A, 1, 59-64, 2002
Scientific journal, English - Principal component analysis of ULF geomagnetic data for Izu islands earthquakes in July 2000
Kaoru Gotoh; Yoshikazu Akinaga; Masashi Hayakawa; Katumi Hattori
J. Atmos. Electr., 22, 1, 1-12, 2002
Scientific journal, English - Monitoring of the ULF electromagnetic disturbances at the station network before EQ in seismic zones of Izu and Chiba peninsulas(Japan)
Kopytenko, Yu. A; V. S. Ismaguilov; K. Hattori; P. M. Voronov; M. Hayakawa; O. A. Molchanov; E. A. Kopytenko; D. B. Zaite
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 11-18, 2002
Research society, English - ULF magnetic anomaly preceding the 1997 Kagoshima Earthquakes
Hattori, K; Y. Akinaga; M. Hayakawa; K. Yumoto; T. Nagao; S. Uyeda
Seismo Electromagnetics (Lithosophere - Atmosphere - Ionosphere Coupling), 19-28, 2002
Research society, English - Statistical analysis of the data from the ULF sensors at Seikoshi Station
Koons, H. C; J. L. Roeder; Y. Hobara; M. Hayakawa; A. C. Fraser-Smith
Seismo Electromagnetics ( Lithosphere - Atmosphere - Ionosphere Coupling), 29-39, 2002
Research society, English - New ULF/ELF observation in Seikoshi, Izu, Japan and the precursory signal in relation with large seismic events at Izu Islands in 2000
Hobara, Y; H. C. Koons; J. L. Roeder; H. Yamaguchi; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 41-44, 2002
Research society, English - Wavelet study of long - period geomagnetic variations associated with the 1989 M = 7 Loma Prieta and two 1997 M = 6 Japanese earthquakes
Alperovich, L. S; V. Zheludev; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 55-60, 2002
Research society, English - Wavelet analysis and seismo - magnetc effect
Lin, Y; Q. Li; M. Hayakawa; X. Zeng
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), TERRAPUB, 61-68, 2002
Research society, English - Mexico City as seismic resonator
Grimalsky, V. V; M. Hayakawa; S. V. Koshevaya; G. N. Burlak; J. Sanchez-Mondragon
Seismo Electromagnetics (Lithosphere - Atomosphere - Ionosphere Coupling), 87-89, 2002
Research society, English - ULF emission due to inductive seismo-electromagnetic effect
Molchanov, O; A. Kulchitsky; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 153-162, 2002
Research society, English - Upward migration of earthquakes as a hint on origin of foreshock activity and other related phenomena
Yunga, S; A. Lutikov; O. Molchanov; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 167-162, 2002
Research society, English - Model of earthquake triggering due to gas-fluid “bubble” upward migration I. Physical rationale.
Iudin, D. I; N. V. Korovkin; O. A. Molchanov; V. V. Surkov; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 177-185, 2002
Research society, English - Model of earthquake triggering due to gas-fluid “bubble” upward migration II. Finite-automaton model
Korovkin, N. V; D. I. Iudin; O. A. Molchanov; M. Hayakawa; V. V. Surkov
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 187-194, 2002
Research society, English - Thermofluctuational mechanism of cracks migration as a model of earthquake preparation
Surkov, V. V; D. I. Iudin; O. A. Molchanov; N. V. Korovkin; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 195-201, 2002
Research society, English - Methods for geophysical data processing in seismc active zones
Troyan, V. N; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 215-221, 2002
Research society, English - Wavelet analysis of disturbances in subionospheric VLF propagation correlated with earthquakes
Hayakawa, M; O. A. Molchanov; N. Shima; A. V. Shvets; N. Yamamoto
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 223-228, 2002
Research society, English - The role of gravity waves in the lithosphere - ionosphere coupling, as revealed from the subionospheric LF propagation data
Miyaki, K; M. Hayakawa; O. A. Molchanov
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), TERRAPUB, 229-232, 2002
Research society, English - Relationship between ELF magnetic fields and Taiwan earthquake
Ohta, K; K. Umeda; N. Watanabe; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 233-237, 2002
Research society, English - Possible premonitory behaviour of LF radiowaves on the occasion of the Slovenia earthquakes (M = 5.2-6.0-5.1) occurred on March - May 1998
Biagi, P. F; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 249-253, 2002
Research society, English - Reception of over-horizon FM signals associated with earthquakes
Fukumoto, Y; M. Hayakawa; H. Yasuda
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 263-266, 2002
Research society, English - Possible influence of seismicity by gravity waves on ionospheric equatrial anomaly from data of IK-24 satellite 1. Search for idea of seismo-ionosphere coupling
Molchanov, O. A; M. Hayakawa; V. V. Afonin; O. A. Akentieva; E. A. Maree
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 275-285, 2002
Research society, English - Possible influence of seismicity by gavity waves on ionospheric equatrial anomaly from data of IK-24 satellite 2. Equatorial anomaly and small-scale ionospheric turbulence
Molchanov, O. A; M. Hayakawa; V. V. Afonin; O. A. Akentieva; E. A. Mareev; V. Yu. Trakhtengerts
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 287-296, 2002
Research society, English - Comparison of simultaneous variations of the ionospheric total electron content and geomagnetic field associated with strong earthquakes
Naman, Sh; L. S; Alperovich, Sh; Wdowinski; M. Hayakawa; E. Calais
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 303-308, 2002
Research society, English - Model variation in atmospheric radio noise caused by pre-seismic modifications of tropospheric conductivity profile
Hayakawa, M; O. A. Molchanov; A. P. Nickolaenko
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), TERRAPUB, 349-352, 2002
Research society, English - Seismo discharge model of anomalous sporadic E ionization before great earthquakes
Ondoh, T; M. Hayakawa
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 385-390, 2002
Research society, English - Coordinated registration of seismogenic effects in the ionosphere by means of remote ground-based and local satellite measurements
Korepanov, V; O. Molchanov; M. Hayakawa; G. Lizunov
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 397-403, 2002
Research society, English - Russian-Japanese complex geophysical observatory in Kamchatka for monitoring of phenomena connected with seismic activity
Uyeda, S; T. Nagao; K. Hattori; Y. Noda; M. Hayakawa; K. Miyaki; O. Molchanov; V. Gladychev; L. Baransky; A. Schekotov; G. Belyaev; E. Fedorov; O. Pokhotelov
Sesmo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 413-419, 2002
Research society, English - Some preliminary results of seismo-electromagnetc research at Complex Geophysical observatory, Kamchatka
Gladychev, V; L. Baransky; A. Schekotov; E. Fedorov; O. Pokhotelov; S. Andreevsky; A. Rozhnoi; Y. Khabazin; G. Belyaev; A. Gorbatikov; E. Gordeev; V. Chebrov
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 421-432, 2002
Research society, English - Infrastructural analysis of geomagnetic field and earthquake prediction
Zeng, X; M. Hayakawa; Y. F. Lin; C. R. Xu
Seismo Electromagnetics (Lithosphere - Atmosphere - Ionosphere Coupling), 463-468, 2002
Research society, English - FDTD simulation and experimental result on VLF scattering by ionospheric perturbations in Earth-ionosphere waveguide
Otsuyama, T; M. Hayakawa
Trans. IEE of Japan, 電気学会, 122-A, 1, 59-64, 2002
Scientific journal, English - Principal component analysis of ULF geomagnetic data for Izu islands earthquakes in July 2000
Gotoh, K; Y. Akinaga; M. Hayakawa; K. Hattori
J. Atmos. Electr., 22, 1, 1-12, 2002
Scientific journal, English - Electromagnetic anomalies associated with 1995 Kobe earthquake
T. Nagao; Y. Enomoto; Y. Fujinawa; M. Hata; M. Hayakawa; Q. Huang; J. Izutsu; Y. Kushida; K. Maeda; K. Oike; S. Uyeda; T. Yoshino
J. Geodynamics, 477-487, 2002
Scientific journal, English - Fractal properties of medium and seismoelectric phenomena
V. V. Surkov; S. Uyeda; H. Tanaka; M. Hayakawa
J. Geodynamics, 519-534, 2002
Scientific journal, English - Subionospheric VLF monitoring for earthquake-related ionospheric perturbations
Shvets, A. V; M. Hayakawa; O. A. Molchanov
J. Atmos. Electr., 87-99, 2002
Scientific journal, English - Investigation of ULF magnetic disturbances in Japan during seismic active period
Kopytenko, Y. A; V. S. Ismaguilov; O. A. Molchanov; E. A. Kopytenko; P. M. Voronov; K. Hattori; M. Hayakawa; D; B. Zaitzev
J. Atmos. Electr., 207-215, 2002
Scientific journal, English - FDTD analysis of ELF wave propagation in inhomogencous subionospheric waveguide models
M. Hayakawa; T. Otsuyama
Appl. Computational Electromagnetics Soc. J., 239-244, 2002
Scientific journal, English - Three-dimensional subionospheric VLF field diffraction by a truncated highly conducting cylinder and its application to the Trimpi effect problem
O. V. Soloviev; M. Hayakawa
Radio Sci., 1079, 2002
Scientific journal, English - Theoretical analysis on the penteration of power line harmonic radiation into the ionosphere
Ando, Y; M. Hayakawa; O. A. Molchanov
Radio Sci., 37, 6, 1093, 2002
Scientific journal, English - Resonances in the Earth-Ionosphere Cavity
Kluwer Acad. Pub, 2002
English - A study on the radiation loss from a bent transmission line
S Lee; M Hayakawa
IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 43, 4, 618-621, Nov. 2001, This paper deals with the radiation loss of bent transmission lines in order to determine the most optimal design for a bent line from the standpoint of radiation loss. We have used the method of moments (MoM) for a numerical analysis on the radiation for different structures of bent lines and we have found that the simplest right-angle bend is the best with the least radiation loss. This theoretical expectation was confirmed experimentally.
Scientific journal, English - Propagation modes of low- and very-low-latitude whistlers
B Singh; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 63, 11, 1133-1147, Jul. 2001, The relative merits of ducted and non-ducted propagation of low-latitude whistlers are examined critically in the light of work done mostly in the Asian countries, India, China, and Japan since 1965. A growing consensus is found in favour of the non-ducted pro-longitudinal mode of propagation for nighttime whistlers, and the ducted mode of propagation in the presence of the equatorial anomaly for daytime whistlers. However, controversy still exists about the propagation mechanism of echo trains of whistlers observed at very low latitudes. An alternative mechanism is suggested involving a nighttime feature of the equatorial anomaly. Some recent unusual results are discussed in more detail: they include the observation of whistler triplets and the frequency and temporal fine structure of whistlers recorded for the first time in a low-latitude ground station. Lastly, further scope for work in the field is indicated. (C) 2001 Elsevier Science Ltd. All rights reserved.
Scientific journal, English - Investigation of the ULF electromagnetic phenomena related to earthquakes: contemporary achievements and the perspectives
Y Kopytenko; Ismagilov, V; M Hayakawa; N Smirnova; Troyan, V; T Peterson
ANNALI DI GEOFISICA, EDITRICE COMPOSITORI BOLOGNA, 44, 2, 325-334, Apr. 2001, The results of ULF electromagnetic signal observations in seismoactive regions prior to earthquakes are presented and discussed. The new differential measurement technique developed in SPbF IZMIRAN for location of the ULF emission sources of space and lithosphere origin is described. The MVC-2DS geophysical instrumentation is introduced as a promising toot for registration of ULF signals related to earthquakes (both seismic and electromagnetic ones). Methods are proposed for ULF data processing to investigate the preparation processes in the earthquake source regions and to distinguish seismogenic signals on the background of space pulsations. Some examples of application of those methods for study of the earthquake precursory signatures are presented. Perspectives of seismo-electromagnetic tomography experiments in seismoactive regions, using MVC-2DS technique, are discussed in relation to the development of earthquake prediction methods.
Scientific journal, English - Scaling characteristies of the ULF geomagnetic fields at the Guam seismoacive area and their dynamics in relation to the earthquake
Smirnova, N; Hayakawa, M; Volobuev, D
European Geophys. Society, March 26-30, 2001, Mar. 2001
Research society, English - Interrelation between ELF transients and ionospheric disturbances in association with sprites and elves
Y Hobara; N Iwasaki; T Hayashida; M Hayakawa; K Ohta; H Fukunishi
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 28, 5, 935-938, Mar. 2001, Red sprites and elves were observed in Japan during the winter of 1998/99 in Hokuriku region by the group of Tohoku Univ. [Fukunishi et al., EOS, 80(46), F217, 1999]. We analyze quantitatively the results from coordinated measurement consisting of ELF transients, VLF subionopheric disturbances and lightning discharges associated with the optical events. We find the clear straightforward relationship between charge transfer of the parent discharge calculated from ELF (f<15 Hz) and the ionospheric disturbances regardless of the types of optical events indicating significant atmosphere-mesosphere-ionosphere coupling. Sprites tend to associate with a large ionospheric disturbance (-13<similar to>+4.6 dB) with a large charge transfer (52 similar to 175 C), whereas a large lightning peak current (+223 similar to +470 kA) (or slow-tail amplitude) leading to the strong EMP is necessary to initiate elves, but with rather small ionospheric disturbances.
Scientific journal, English - 三宅島噴火に伴う伊豆諸島地震におけるULF 帯地磁気信号の主成分解析
後藤 薫; 秋永和計; 早川正士; 服部克巳
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 地震に伴うVLF/LF大地震離層導波管伝播異常およびその発生機構について
宮本圭介; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 地震に伴うVHF 帯伝播異常について
福元康仁; 早川正士; 保田 彪
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 地震に伴うULF 電磁放射について
秋永和計; 早川正士; 服部克巳; 湯元清文
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - ULF Observation in Seikoshi and Recent Seismic Events in Izu
吉原容英; 山口弘輝; 早川正士; J. Roeder; H. Koons
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - Polarization analysis of ULF data at Seikoshi
H. Yamaguchi; M. Hayakawa; Y. Hobara
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
English - VLF 局を用いた地震前兆現象の観測（２）
溝口裕史; 太田健次; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - ULF 帯電磁波と台湾地震との関係
梅田浩二; 太田健次; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - VLF ターミネータータイム法による地震の予知率／空報率の検討
澤谷琢磨; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 地震に伴う40kHz 電波の有限要素法を用いた伝播異常の解析
石川雅澄; 早川正士; 馬場清英
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - Guam地震におけうULF 放射に関するフラクタル解析
弘中 豊; 秋永和計; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 鳥取西部地震に伴うGPS 衛星データを用いた電離層擾乱の観測
大坂 健; 早川正士; ヒラリメレズ
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 京都舞鶴観測データを用いた地震に伴う40kHz 電波伝播異常について
高杉庸平; 宮木圭介; 石川雅澄; 澤谷琢磨; 早川正士; 西村萬平
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - ビアク地震に伴うULF 磁界異常
服部克巳; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - ELF 帯シューマン共振現象と世界雷活動との関係
林田剛史; 岩崎夏子; 芳原容英; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - ELF 帯トランジェントを用いた世界雷分布における誤差および空電源の特性について
岩崎夏子; 林田剛史; 早川正士; 芳原容英
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - 雷雲の電荷分布と下部電離層擾乱域との関係
大津山卓哉; 早川正士
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
Japanese - Fractal Analysis of winter lightning data
T. Nakamura; M. Hayakawa; T. Hayakawa; T. Hanada; K. Michimoto; Y. Hobara
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
English - Atmosphere-mesosphere-ionosphere coupling deduced from Japanese winter lightning data
Y. Sanou; N. Iwasaki; T. Hayashida; M. Hayakawa; Y. Hobara
日本大気電気学会，第64回研究発表会，平成13年１月９日，10日，千葉大, Jan. 2001
English - A role of the second-order cyclotron resonance effect in a self-consistant approach to triggered VLF emissions
Trakhtengerts, V; Y. Y. Hobara; A. G. Demekhov; M. Hayakawa
J. Geophys. Res., 106, A3, 3897-3904, 2001
Scientific journal, English - Seismic effect on the propagation of subionospheric LF radio waves in Italy
Fukumoto, Y; M. Hayakawa; P. F. Biagi
J. Atmos. Electr., 21, 1, 21, 1, 1-7, 2001
Research society, English - 雷放電による下部電離層の電離異常
大津山卓哉; 早川正士; 太田健次
J. Atmos. Electr., 21, 1, 49-60, 2001
Japanese - Interrelation between ELF transients and ionospheric disturbances in association with sprites and elves
Hobara; Y. N. Iwasaki; T. Hayashida; M. Hayakawa; K. Ohta; H. Fukunishi
Geophys. Res. Lett., 29, 5, 935-938, 2001
Research society, English - 多素子トランスデューサによる静磁表面波の励振
安藤芳晃; 官 寧; 八代健一郎; 大川澄雄; 早川正士
2001年電子情報通信学会総合大会講演論文集，C-2-53, 100, 2001
Japanese - 減衰型無限要素を加味した有限要素法による有限グラウンド上のマイクロストリップ線路のクロストーク問題の解析
李成圭; 早川正士
電気学会論文誌 Ａ, Trans. IEE of Japan, 2001
Japanese - Seismic effect on the propagation of subionospheric LF radio waves in Italy
Fukumoto, Y; M. Hayakawa; P. F. Biage
J. Atmos. Electr., 2001
Research society, English - 雷放電による下部電離層の電離異常
大津山卓哉; 早川正士; 太田健次
Ｊ．Ａｔｍｏｓ．Ｅｌｅｃｔｒ．, 49-60, 2001
Research society, Japanese - A role of the second-order cyclotron resonance effect in a self-consistent approach to triggered VLF emissions
V. Trakhtengerts; Y. Hobara; A. G. Demekhov; M. Hayakawa
J. Geophys. Res., 3897-3904, 2001
Research society, English - VLF monitoring of atmosphere-ionosphere boundray as a tool to study planetary waves evolution and seismic influence
O.A. Molchanov; M. Hayakawa
Phys. Chem. Earth, 453-458, 2001
Research society, English - Radiation from bent transmission lines
S. Lee; M. Hayakawa; N. Smirnova
IEICE Trans. Ins. Electr. Engrs. of Japan, 121-A, 10, 893-898, 2001
Scientific journal, English - Electromagnetic phenomena associated with earthquakes: Review
M. Hayakawa
Trans. Ins. Electr. Engrs. of Japan, 121-A, 10, 893-898, 2001
Scientific journal, English - 地震に伴う電離層内電磁気現象
早川正士
静電気学会誌, 25, 5, 256-262, 2001
Scientific journal, Japanese - Lightning effect in mesosphere and associated ELF radio signals
M. Hayakawa; A. P. Nickolaenko
Proc. Indian Nat'Science Academy, 4&5, 509-529, 2001
Scientific journal, English - Possible earthquake precursors revealed by LF radio signals
P. F. Biagi; R. Piccolo; A. Ermini; S. Martellucci; C. Bellecci; M. Hayakawa; V. Capozzi; S. P. Kingsley
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 99-104, 2001, Among radio signals, low frequency (LF) radio signals lie in the band between 30-300 kHz. Monitoring equipment with the ability to measure the electric strength of such signals at field sites, were designed and assembled in Italy. From 1993 onwards, the electric field strength of the MCO (216 kHz, France) broadcasting station has been collecting measurements at two sites in central Italy that were chosen according to very low noise levels. At the end of 1996, radio signals from the CLT (189 kHz, Italy) and CZE (270 kHz, Czech Republic) broadcasting stations were included in the measurements. Meteorological data from central Italy were also collected over the same time period in order to study the influence of weather conditions on the experimental measurements. During the monitoring period, we observed some evident attenuation of the electric field strength in some of the radio signals at some of the receivers. The duration of the attenuation observed was several days, so it could possibly be related to particular meteorological conditions. On the other hand, this phenomenon might represent precursors of moderate (3.0 <= M <= 3.5) earthquakes that occurred near the receivers (within 50 km) along the transmitter-receiver path. In this case, it is possible that the pre-seismic processes could have produced irregularities in the troposphere, such as ducts, reflecting layers and scattering zones, so that some local troposphere defocusing of the radio signals might have occurred. These observations were related only to moderate earthquakes and in these cases, suitable meteorological conditions were probably needed to observe the effect. Between February - March 1998, we observed at one measuring site, a significant increase in the CZE electric field strength. Unfortunately, we could not use the data of the other receiver in this case, due to frequent interruptions in the data set. The increase might have been a precursor of the strong seismic sequence (M= 5.0-6.0) that occurred during March - May 1998 in Slovenia at a location over 400 km from the receiver, but lying in the middle of the transmitter-receiver path. In this case, it is possible that an ionospheric disturbance, produced by the pre-seismic processes, might have occurred.
Scientific journal, English - VLF/LF sounding of the lower ionosphere to study the role of atmospheric oscillations in the lithosphere-ionosphere coupling
O.A. Molchanov; M. Hayakawa; K. Miyaki
Adv. Polar Upper Atmos. Res., National Institute of Polar Research, 15, 15, 146-158, 2001, It is shown that sounding of the lower ionosphere boundary by subionospheric signals from powerful VLF/LF transmitters can be a useful tool for the investigation of Planetary Waves (PW) with periods in a range of 2-30 days. A specific spring-time transition in the PW dynamic periodograms is revealed from our analysis of several years data using Tsushima, Japan VLF transmitter (10.2kHz) along the path with length of about 1000km. Earthquake influence m the periodograms could be sometime recognized as an appearance of specific wavelets. We discuss a possibility of PW transportation from the bottom to the upper atmosphere as modulation of shorter-scale gravity waves (GW) inside the troposphere and subsequent demodulation of the GW at the atmosphere-ionosphere boundary for the explanation of observational results. The existence of modulation due to gravity waves in LF signal amplitude is presented to support the above hypothesis.
Scientific journal, English - ULF magnetic emission connected with under sea bottom earthquakes
V.S. Ismaguilov; Y.A. Kopytenko; K. Hattori; P.M. Voronov; O.A. Molchanov; M. Hayakawa
Natural Hazards System Sci., 1, 23-32, 2001
Scientific journal, English - A precursory ULF signature for the Chi-Chi earthquake in Taiwan
Y. Akinaga; M. Hayakawa; J. Y. Liu; K. Yumoto; K. Hattori
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 33-36, 2001, ULF emission data at Lunping (epicentral distance, 120 km) have been analysed for the Chi-chi earthquake (with magnitude 7.6 and depth of 11 km) in Taiwan which occurred on 21 September 1999. Simple intensity analyses have not yielded any significant results but we have found, based on the analysis of polarization (the ratio of vertical magnetic field component Z to the horizontal component G), that the polarization (Z/G) showed a significant enhancement for two months before the earthquake. This kind of temporal evolution of polarization seems to be very similar to previous results, so that it is highly likely that this phenomenon may be associated with the Chi-Chi earthquake. Also, the comparison of the results of polarization analyses, by changing the signal threshold, has given us an approximate intensity of the seismogenic emission of the order of the monthly mean value.
Scientific journal, English - Inductive seismo-electromagnetic effect in relation to seismogenic ULF emission
O. Molchanov; A. Kulchitsky; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 61-67, 2001, During the seismic wave propagation through the crust, the electromagnetic pulse can originate due to MHD conversion in this conductive medium. On the assumption of simple models of seismic wave excitation and attenuation, the problem is reduced to the analysis of a diffusion-like equation for a vector potential function. In this way, we need to change the classical gauge condition. A semi-analytical form of the solution is obtained in a case with constant ground conductivity. Dependencies of the electric and magnetic field components and the pulse duration on distance and crust conductivity have been computed in detail. The results could be useful for the explanation of electromagnetic signals related to coseismic, foreshock and aftershock activity.
Scientific journal, English - ULF/ELF emissions observed in Japan, possibly associated with the Chi-Chi earthquake in Taiwan
K. Ohta; K. Umeda; N. Watanabe; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 37-42, 2001, ULF/ELF emission observation has been performed at Nakatsugawa observatory (geographic coordinates; 35.4 degrees N, 137.5 degrees E, Gifu prefecture) since January 1999. The equipment consists of three-orthogonal magnetic sensors (induction coils), amplifiers, A/D converters and the data logger with a computer. The frequency range of observation is from 0.001 Hz to 50 Hz. The serious changes in ELF magnetic field intensity were detected on 20 September 1999, in such a way that the ELF noise level is found to increase by more than 5 dB from the normal level for about 1.5 h during 21:30-23:00 Japanese Standard Time on 20 September and also the upper limit extends up to 50 Hz. A careful comparison with the nearby lightning as detected by VLF, enables us to confirm that this abnormal ELF noise level increase is not due to the nearby lightning. The phase difference of these ELF emissions (B-X, B-Y) was measured, and indicates that these ELF emissions are linearly polarized, suggesting that they have propagated in the subionospheric waveguide over long distances. This polarization result enables us to perform goniometric direction finding and the result shows that the main direction of these ULF/ELF emissions is toward Taiwan. Hence, it is likely that such ULF/ELF emissions are associated with the Chi-Chi earthquake in Taiwan at 02:27 Japanese Standard Time on 21 September 1999 (M = 7.6; depth 11 km).
Scientific journal, English - Scaling characteristics of ULF geomagnetic field at the Guam seismoactive area and their dynamics in reation to the earthquake
N. Smirnova; M. Hayakawa; K. Gotoh; D. Volobuev
Natural Hazards Earth System Sci., 1, 119-126, 2001
Scientific journal, English - Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity
S. Uyeda; T. Nagao; K. Hattori; M. Hayakawa; K. Miyaki; O. Molchanov; V. Gladychev; L. Baransky; A. Chtchekotov; E. Fedorov; O. Pokhotelov; S. Andreevsky; A. Rozhnoi; Y. Khabazin; A. Gorbatikov; E. Gordeev; V. Chebrov; V. Sinitzin; A. Lutikov; S. Yunga; G. Kosarev; V. Surkov; G. Belyaev
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 3-7, 2001, Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range Delta F = 0.5 - 40 Hz) and meteorological recordings, together with seismo-acoustic (Delta F = 30 - 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations (Delta F = 0.003 - 30 Hz), three-component electric potential variations (Delta F <= 1.0 Hz), and VLF transmitter's signal perturbations (Delta F similar to 10 - 40 kHz).
Scientific journal, English - Comparison of simultaneous variations of the ionospheric total electron content and geomagnetic field associated with strong earthquakes
Sh. Naaman; L. S. Alperovich; Sh. Wdowinski; M. Hayakawa; E. Calais
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 53-59, 2001, In this paper, perturbations of the ionospheric Total Electron Content (TEC) are compared with geomagnetic oscillations. Comparison is made for a few selected periods, some during earthquakes in California and Japan and others at quiet periods in Israel and California. Anomalies in TEC were extracted using Global Positioning System (GPS) observations collected by GIL (GPS in Israel) and the California permanent GPS networks. Geomagnetic data were collected in some regions where geomagnetic observatories and the GPS network overlaps. Sensitivity of the GPS method and basic wave characteristics of the ionospheric TEC perturbations are discussed. We study temporal variations of ionospheric TEC structures with highest reasonable spatial resolution around 50 km. Our results show no detectable TEC disturbances caused by right-lateral strike-slip earthquakes with minor vertical displacement. However, geomagnetic observations obtained at two observatories located in the epicenter zone of a strong dip-slip earthquake (Kyuchu, M = 6.2, 26 March 1997) revealed geomagnetic disturbances occurred 6-7 h before the earthquake.
Scientific journal, English - Application of a wavelet technique for the detection of earthquake signatures in the geomagnetic field
L. Alperovich; V. Zheludev; M. Hayakawa
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 1-2, 75-81, 2001, We developed an algorithm especially adapted to single-station wavelet detection of geomagnetic events, which precede or accompany the earthquakes. The detection problem in this situation is complicated by a great variability of earthquakes and accompanied phenomena, which aggravates finding characteristic features of the events. Therefore we chose to search for the characteristic features of both "disturbed" intervals (containing earthquakes) and "quiet" recordings. In this paper we propose an algorithm for solving the problem of detecting the presence of signals produced by an earthquake via analysis of its signature against the existing database of magnetic signals. To achieve this purpose, we construct the magnetic signature of certain earthquakes using the distribution of the energies among blocks, which consist of wavelet packet coefficients.
Scientific journal, English - Study of electromagnetic emissions associated with seismic activity in Kamchatka region
V. Gladychev; L. Baransky; A. Schekotov; E. Fedorov; O. Pokhotelov; S. Andreevsky; A. Rozhnoi; Y. Khabazin; G. Belyaev; A. Gorbatikov; E. Gordeev; V. Chebrov; V. Sinitsin; A. Lutikov; S. Yunga; G. Kosarev; V. Surkov; O. Molchanov; M. Hayakawa; S. Uyeda; T. Nagao; K. Hattori; Y. Noda
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, COPERNICUS GESELLSCHAFT MBH, 1, 3, 127-136, 2001, A review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July-November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented.
Scientific journal, English - Disturbance in LF radio-signals as seismic precursors
P.F.Biagi; R.Piccolo; A.Ermini; S.Martellucci; C.Bellecci; M.Hayakawa; S.P.Kingsley
Annali Di Geofisica, 44, 5/6, 2001
Scientific journal, English - 地震に伴う電磁現象
早川正士
電気学会技術報告, 836, 65, 2001
Scientific journal, Japanese - Investigation of over-horizon VHF radio signals associated with earthquakes
Y. Fukumoto; M. Hayakawa; H. Yasuda
Natural Hazards Earth System Sci., 101-112, 2001, Peer-reviwed
Scientific journal, English - NASDA/UEC Activity on Earthquake. Signatures on subionospheric VLF/LF propagation
Hayakawa, M; O. A. Molchanov; K. Miyaki; Y. Fukumoto; M. Ishikawa; T. Sawaya
Plenary Talk, Int'l Workshop on Seismo-Electromagnetics and Space Science, Agra（India）, 1, Dec. 2000
English - Electromagnetic Phenomena Associated with earthquakes
Hayakawa, M
Invited Talk, Proc. 2000 Japan-China Joint Meeting on Optical Fiber Science and Electromagnetic Theory, Osaka, Dec. 4-6, 2000, 271-274, Dec. 2000
English - Cyclotron amplification of whistler waves by nonstationary electron beams in an inhomogeneous magnetic field
AG Demekhov; VY Trakhtengerts; Y Hobara; M Hayakawa
PHYSICS OF PLASMAS, AMER INST PHYSICS, 7, 12, 5153-5158, Dec. 2000, The linear amplification of whistler waves with varying frequency by beams of energetic electrons in the inhomogeneous magnetic field is studied. Rigorous treatment developed by Trakhtengerts et al. [Phys Plasmas 6, 692 (1999)] for the distribution function with a steplike deformation over parallel velocities is applied here for the delta -like distribution which is appropriate for triggered emissions. The formalism developed enables one to determine the one-hop amplification of a wavelet with variable frequency and the "optimal" spatio-temporal variation of the frequency corresponding to the maximum amplification; we show this variation to coincide with the so-called second-order cyclotron resonance condition, similarly to the case of the steplike distribution. The results allow one to compare the dependence of the maximum amplification on characteristic parameters of a plasma in the magnetic trap for smooth, steplike, and beamlike distributions. (C) 2000 American Institute of Physics. [S1070-664X(00)00712-6].
Scientific journal, English - A finite-state automation model of surface discharge dynamics for electromagnetic compatibility problems
Adalyov, A. S; M. Haykakawa; D. I. Iudin; N. V. Korovkin; E. E. Selina; V. Y. Trakhtengertz
Proc. EMC Europe 2000 Brugge, 437-442, Sep. 2000
English - NASDA's Earthquake Remote Sensing Frontier Project, Plenary Opening Talk
M. Hayakawa
Int'l Workshop on Seisomo Electromagnetics, Chofu, Sep. 2000
English - Locating global lightning from a single station based on ELF transient observation
Iwasaki, N; T. Hayashida; Y. Hobara; M. Hayakawa
Proc. 2000 Int'l Symp. on Ant. Prop., Fukuoka, 369-372, Aug. 2000
English - Searching for the earthquake precursor signatures in geophysical data: A complex approach
Troyan V; Smirnova, N; Hayakawa, M; Kopytenko; and Yu; Peterson, Th
Abstracts of Internationa Geological Congress, Rio-de-Janeiro, Brasil（CD）, Aug. 2000
English - 伊豆群発地震におけるULF 帯電磁放射観測信号の主成分分析及び独立成分分析
後藤 薫; 早川正士
日本大気電気学会第63回研究発表会，平成12年７月13日，14日，秋田県大, Jul. 2000
Japanese - ULF 帯電磁波と地震前兆現象の関係
梅田浩二; 太田健次; 早川正士
日本大気電気学会第63回研究発表会，平成12年７月13日，14日，秋田県大, Jul. 2000
Japanese - VLF 局を用いた地震前兆現象の観測
溝口裕治; 太田健次; 早川正士
日本大気電気学会第63回研究発表会，平成12年７月13日，14日，秋田県大, Jul. 2000
Japanese - 地震に伴うVHF 帯電波伝搬異常
福元康仁; 早川正士; 保田 彪
日本大気電気学会第63回研究発表会，平成12年７月13日，14日，秋田県大, Jul. 2000
Japanese - 電雲内の電荷分布（不均質性）と下部電離層擾乱の関係
大津山卓哉; 早川正士
日本大気電気学会第63回研究発表会，平成12年７月13日，14日，秋田県大, Jul. 2000
Japanese - Interrelation between ELF Transients and Ionospheric Disturbances in Association with Mesospheric Optical Events
芳原容英; 岩崎夏子; 早川正士; 太田健次; 福西 浩
日本大気電気学会第63回研究発表会，平成12年７月13日，14日，秋田県大, Jul. 2000
English - Theory and experiment on radiation from a bent transmission line
Ishibashi, N; S. K. Lee; M. Hayakawa
Proc. 15th Int'l Wroclaw Symp. on EMC, 275-279, Jun. 2000
English - Fractal properties of high- and low-latitude ULF emissions and their relation to geomagnetic activity
Smirnova N; Hayakawa M
Book of abstracts Int. Conf. on Problems of Geocosmos（May 22-26, 2000, St. Petersburg, Russia）, 61, May 2000
English - Dynamics of scaling characteristics of the ULF geomagnetic fields in a seismoactive region of Guam Island and its relation to the earthquake
Smirnova N; M. Hayakawa; T. Ito
Book of abstracts Int. Conf. on Problems of Geocosmos（May 22-26, 2000, St. Petersburg, Russia）, 111, May 2000
English - Monitoring ULF magnetic disturbances and schemes for recognizing earthquake precursors
Haykawa M; Kopytenko Yu. A; Smirnova N; Troyan V; Peterson Th
Book of abstracts Int. Conf. on Problems of Geocosmos（May 22-26, 2000, St. Petersburg, Russia）, 105, May 2000
English - ULF electromagnetic precursors for an earthquake at Biak, Indonesia on February 17, 1996
M Hayakawa; T Itoh; K Hattori; K Yumoto
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 27, 10, 1531-1534, May 2000, ULF electromagnetic emissions associated with a large earthquake occurred at Biak Island, Indonesia at 5h 59m UT on February 17, 1996 (magnitude (Mw) = 8.2 and depth = 20 km from USGS catalog), have been investigated on the basis of ULF magnetic observations at two stations, Biak and Darwin in Australia (about 1,200 km apart). Though a simple analysis of magnetic field intensity (horizontal and vertical magnetic field components) at both stations was found to be closely correlated with geomagnetic Sigma Kp activity, a detailed analysis of the difference of H and Z components at the two stations, the polarization analysis (Z/H) and fractal analysis (frequency spectrum slope) at these two stations has yielded that the ULF emissions (in the frequency range from 5 mHz to 30 mHz) about 1.5-1.0 months before the quake are likely to be a precursory signature of the quake with its intensity on the order of 0.2-0.3 nT.
Scientific journal, English - Formation of electron beams by the interaction of a whistler wave packet with radiation belt electrons
Y Hobara; VY Trakhtengerts; AG Demekhov; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 62, 7, 541-552, May 2000, The purpose of this paper is to discuss the properties of electron beams formed by cyclotron interactions between radiation belt electrons and a quasi-monochromatic whistler wave packet from a ground-based VLF transmitter. The beams are formed due to trapping of the electrons at the forward edge of the wave packet, their acceleration inside the wave packet, the escape of the accelerated electrons from the moving backward edge of the wave packet, and their following free motion in an inhomogeneous magnetic field. A combination of these processes provides the main features of the spatial-temporal evolution of the beams which are investigated both analytically and numerically. It is shown that one or two beams can appear at one point at the same time, and that the density of the beams increases during their expansion. Motion of the pumping wave packet in the inhomogeneous magnetic field provides the variations of the initial velocity and position of the beam injection which change the spatial and temporal gradients of the parallel velocity of the beam, in contrast with the case of the pure adiabatic motion of an individual electron. Such a behaviour can be significant for the generation of secondary emissions. Numerical calculations demonstrate a wide variety of the spatio-temporal patterns of the beam parallel velocity depending on the plasma and wave packet parameters. It is shown that the most significant parameters which determine the beam characteristics are the wave packet length about the equator, its group velocity, and the initial energy and pitch angle of the electrons. (C) 2000 Elsevier Science Ltd. All rights reserved.
Scientific journal, English - The formation of ionosphere-magnetosphere ducts over the seismic zone
VM Sorokin; VM Chmyrev; M Hayakawa
PLANETARY AND SPACE SCIENCE, PERGAMON-ELSEVIER SCIENCE LTD, 48, 2-3, 175-180, Feb. 2000, A physical mechanism of whistler duct formation due to electric field growth in the ionosphere above the seismic zone is considered. The ducts are plasma irregularities, stretched along geomagnetic field, with the transverse spatial scale of the order of 10 km and with the relative plasma density variation over the background value of the order of 10%. It is shown that such structures are formed by the field-aligned currents as a result of the interaction between the ionospheric electric field and the horizontal irregularities of the ionospheric conductivity. The conductivity irregularities are excited by the instability of acoustic-gravity waves (AGW), developed in the ionosphere when the electric field exceeds a certain critical value. Since the ionosphere conductivity disturbances depend on the AGW parameters, the wave amplitude growth results in modulating the conductivity and forming the additional currents due to the ionospheric electric field. The Joule heat released by these currents amplifies the AGW amplitude and, hence, the magnitude of the conductivity variations, which resulted in a growth of the oscillations and in the exponential growth of the disturbances, associated with the acoustic-gravity wave. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.
Scientific journal, English - VLE electromagnetic noise bursts related to major sesmic activities observed at Agra
R. Singh; B. Singh; V. Bansal; M. Hayakawa
J. Atmos. Electr., 20, 1, 7-20, 2000
English - Monitoring ULF magnetic disturbances, and schemes for recognizing earthquake precursors
M Hayakawa; Y Kopytenko; N Smirnova; Troyan, V; TH Peterson
PHYSICS AND CHEMISTRY OF THE EARTH PART A-SOLID EARTH AND GEODESY, PERGAMON-ELSEVIER SCIENCE LTD, 25, 3, 263-269, 2000, Specific electromagnetic signals in the ULF range, which were observed in seismoactive regions prior to some strong and moderate earthquakes, are discussed with respect to the earthquake prediction problem. Characteristic features of such "seismogenic" ULF emissions are pointed out and compared with differential peculiarities of the ULF emissions of space origin. A new magnetometer technique for locating ULF emission sources is described. Methods are proposed for ULF data processing to investigate preparation activity within the earthquake source region, and to distinguish seismogenic signals from the background of space pulsations. Possible generation mechanisms of the ULF electromagnetic signals in seismic hazard systems are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.
Scientific journal, English - On a possibility to monitor seismic activity using satellites
M. Hayakawa; O. A. Molchanov; T. Kodama; T. Tanaka; T. Igarashi
Adv. Space. Res., 26, 6, 993-996, 2000
English - Effect of earthquakes on lower ionosphere as found by subionospheric VLF propagation
M. Hayakawa; O. A. Molchanov
Adv. Space. Res., 26, 8, 1273-1276, 2000
English - Plasma density variations observed on a satellite possibly related to seismicity
M. Hayakawa; O. A. Molchanov; T. Kodama; V. V. Afonin; O. A. Akentieva
Adv. Space. Res., 26, 8, 1277-1280, 2000
English - NASDA earthquake remote sensing frontier research -Feasibility of satellite observation of seismoelectromagnetics
T. Kodama; O. A. Molchanov; M. Hayakawa
Adv. Space. Res., 26, 8, 1281-1284, 2000
English - Comment on "Model of red sprites due to intracloud fractal lightning discharges"
A. P. Nickolaenko; M. Hayakawa
Radio Sci., 35, 3, 921, 2000
English - Electromagnetic phenomena associated with earthquakes
Hayakawa, M
Bulletin of Univ. of Electro-Comm., 13-1, The University of Electro-Communications, 13, 1, 1-6, 2000
English - Three-dimensional ray-tracing for very low latitude whistlers, taking into account the latitudinal and longitudinal gradients of ionosphere
Ohta, K; M. Hayakawa
J. Geophys. Res., 105, A8, 18, 895-18, 900, 2000
English - New ELF observation site in Moshiri, Hokkaido Japan and the results of preliminary data analysis
Hobara, Y; N. Iwasaki; T. Hayashida; T. Tsuchiya; E. R. Williams; M. Sera; Y. Ikegami; M. Hayakawa
J. Atmos. Electr., 20, 2, 99-109, 2000
English - Wide-band ULF/ELF magnetic field measurement in Seikoshi, Izu Japan and some results from preliminary data analysis in relation with seismic activity
Hobara; Y. H. Yamaguchi; T. Watanabe; Y. Akinaga; H. C. Koons; J. L. Roeder; M. Hayakawa
J. Atmos. Electr., 20, 2, 111-121, 2000
English - On the association of anomalies in subionospheric VLF propagation at Kasugai with earthquakes in the Tokai area, Japan
Ohta, K; K. Makita; M. Hayakawa
J. Atmos. Electr., 20, 2, 85-90, 2000
English - 地震前兆波の同定問題に対するブランド信号分離アルゴリズム応用の提案
後藤 薫; 早川正士
電子情報通信学会論文誌A, 183-A, 12, 1477-1485, 2000
Japanese - 地震発生過程におけるアコースティックエミッション応答
Gorbatikov, A; O. A. Molchanov; M. Hayakawa; S. Uyeda; K. Hattori; T. Nagao; A. Nikolaev
地震ジャーナル，30, 56-63, 2000
Japanese - Cellular automation model of lightning discharge preliminary stage
Hayakawa, M; D. I. Iudin; N. V. Korovkin; V. Y. Trakhtengertz
ibid, 523-527, 2000
English - Three-dimensional ray-tracing for very low latitude whistlers, with considering the latitudinal and longitudinal gradients of the ionosphere
Ohta, K; H. Kanzaki; M. Hayakawa
ibid, 536-539, 2000
English - ULF electromagnetic precursors for an earthquake at Biak, Indonesia on February 17, 1996
Hayakawa, M; T. Itoh; K. Hattori; K. Yumoto
ibid, 546-549, 2000
English - On the association of anomalous subionospheric VLF propagation at Kasugai with earthquakes center of Japan
Ohat, K; K. Makita; M. Hayakawa
ibid, 561-564, 2000
English - Geoelectromagnetic disturbances and their effect on technological systems
Haykawa, M; R. Pirjola
URSI Comm. E Open meeting, ibid, 915-920, 2000
English - Propagation and direction finding of Schumann resonances in relation with the global thunderstorm activity
Hayashida, T; Y. Hobara; N. Iwasaki; M. Hayakawa
ibid, 373-376, 2000
English - Relationship between ELF transients and ionospheric disturbances in association with sprites and elves
Hobara, Y; T. Hayashida; N. Iwasaki; M. Hayakawa; K. Ohta; H. Fukushini
ibid, 377-380, 2000
English - ULF emissions associated with earthquakes in Kyushu
Akinaga, Y; K. Hattori; M. Hayakawa; K. Yumoto
ibid, 385-388, 2000
English - Precursory anomalies of earthquakes on short distance propagation of 40 kHz signals
Miyaki, K; M. Hayakawa
ibid, 1043-1046, 2000
English - A study on radiation loss from bent transmission lines
Lee, S. K; M. Hayakawa
ibid, 1589-1592, 2000
English - Seismic effect on the propagation of subionospheric LF radio waves in Italy
Fukumoto, Y; M. Hayakawa; P. Biagi
ibid, 1247-1250, 2000
English - Self-consistent theory of triggered VLF emissions: An analytical approach
Hobara, Y; V. Y. Trakhtengertz; A.G.Demekhov; M. Hayakawa
ibid, 1267-1270, 2000
English - Characteristics of blind deconvolution with natural gradient method
Gotoh, K; M. Hayakawa
ibid, 1427-1430, 2000
English - Fractal properties of seismoelectric phenomena
V. V. Surkov; S. Uyeda; T. Nagao; M. Hayakawa
ibid, 2000
English - Monitoring of the ULF electromagnetic disturbances at the station network before EQ in seismic zones of Izu and Chiba peninsula（Japan）
Yu. A. Kopytenko; K. Hattori; P. M. Voronov; M. Hayakawa; V. S. Ismaguilov; O. A. Molchanov; E. A. Kopytenko; D. B. Zaitsev
ibid, 2000
English - Statistical analysis of the data from the ULF sensors at Seikoshi station
H. C. Koons; J. L. Reoder; Y. Hobara; M. Hayakawa
ibid, 2000
English - Identification of natural and man-made ULF/ELF emissions using the high-resolution data from Seikoshi station
J. L. Roeder; H. C. Koons; Y. Hobara; M. Hayakawa
ibid, 2000
English - New ULF/ELF measssurement in Seikoshi, Izu peninsula Japan,
Y. Hobara; T. Yamaguchi; Y. Akinaga; T. Watanabe; H. C. Koons; J. L. Roeder; M. Hayakawa
ibid, 2000
English - Acoustic and magnetic emissions at Matsushiro（association with nearby earthquekes）：Previous and recent results
A. N. Gorbatikov; O. A; Molchaanov; M. Hayakawa; S. Uyeda; K. Hattori; T. Nagao; P. Maltsev
ibid, 2000
English - ULF magnetic emission induced by foreshock and aftershock seismic activity due to inductive seismomagnetic effect
O. A. Molchanov; N. V. Korovkin; M. Hayakawa
ibid, 2000
English - Fractal characteristics of the ULF geomagnetic fields in seismoactive regions and their dynamics in relation to earthquakes
N. Smirnova; M. Hayakawa; T. Itoh
ibid, 2000
English - Comparative wavelet study of long-period geomagnetic variation associate with the 1989 M=7.1 Loma Prieta and two 1997 M-6.1 Japanese earthquakes
L. Alperovich; V. Zheludev; M. Hayakawa
ibid, 2000
English - Neural approaches to detect seismogenic ULF wave in the noisy environment
K. Goto; M. Hayakawa
ibid, 2000
English - Relationship between ELF magnetic fields and Taiwan earthquakes
K. Ohta; K. Umeda; M. Hayakawa
ibid, 2000
English - Preseismic degassing and earthquake initiation
D. I. Iudin; N. V. Korovkin; O. A. Molchanov; V. Surkov; M. Hayakawa
ibid, 2000
English - Explosive degassing cellular automaton model
N. V. Korovkin; D. I. Iudin; O. A. Molchanov; V. Surkov; M. Hayakawa
ibid, 2000
English - Model variations in atmospheric radio noise caused by pre-seismic modifications of tropospheric conductivity profile
M. Hayakawa; O. A. Molchanov; A. P. Nickolaenko
ibid, 2000
English - Wavelet analysis of disturbances in subionospheric VLF propagation correlated to earthquakes
M. Hayakawa; O. A. Molchanov; N. Shima; A. V. Shvets; N. Yamamoto
ibid, 2000
English - Premonitory behaviour of LF radiowaves on the occasion of the Umbria-Marche（Central Italy）earthquake（M=5.5）occurred at March 26,1998
P. F. Biagi; M. Hayakawa
ibid, 2000
English - Reception of over-horizon FM transmitter signals and their association with earthquakes
Y. Fukumoto; M. Hayakawa; H. Yasuda
ibid, 2000
English - Possible influence of seismicity through gravity waves on ionospheric equatorial anomaly from data of 1K-24 satellite
O. A. Molchanov; M. Hayakawa; V. V. Afonin; O. A. Akentieva; E. A. Mareev; V. Yu. Trakhtengerts
ibid, 2000
English - A preliminary comparison of simultaneous variation of the ionospheric tatal electron content and geomagnetic field associated with two strong earthquakes
L. Alperovich; Sh. Naman; Sh. Wdowinski; M. Hayakawa
ibid, 2000
English - Statistical study for equatorial anomaly from high apogee satellite APEX and low-apogee satellite COSMOS-900
V. V. Afonin; O. A. Akentiava; O. A. Molchanov; M. Hayakawa
ibid, 2000
English - Radio-sounding of the seismogenic inhomogeneities in ionosphere using SICH-1M satellite
V. Korepanov; O. Molchanov; M. Hayakawa; G. Lizunov
ibid, 2000
English - Earthquake predictability as it follows from EM precursors study
I. I. Rokityansky; M. Hayakawa
ibid, 2000
English - Pre-earthquake ULF electromagnetic perturbations as result of inductive seismonagnetic phenomena during microfracturing
V. V. Surkov; O. A. Molchanov; M. Hayakawa
ibid, 2000
English - Thermofluctuational mechanism of cracks migration as a model of earthquake preparation
V. V. Surkov; D. I. Iudin; O. A. Molchanov; N. V. Korovkin; M. Hayakawa
ibid, 2000
English - Magnetic location of the ULF magnetic disturbances sources in sesmic zones of Izu and Chiba peninsula（Japan）
Yu. A. Kopytenko; V. S. Ismaguilov; K. Hattori; M. Hayakawa; O. A. Molchanov
ibid, 2000
English - Some peculiarities of magnetotelluric sounding in seismic zones of Izu and Chiba peninsula（Japan）
M. Yu. Smironov; Yu. A. Kopytenko; K. Hattori; M. Hayakawa; O. A. Molchanov
ibid, 2000
English - Consideration of the earthquake prepartion processes on the basis the SOC（Self-organized Criticality）concept, and schemes for recognizing earthquake precursors
M. Hayakawa; V. Troyan; N. Smirnova; Yu. Kopytenko; Th. Peterson
ibid, 2000
English - ULF emissions associated with earthquakes
Y. Akinaga; K. Hattori; M. Hayakawa; K. Yumoto
ibid, 2000
English - ULF Geomagnetic observation system at RIKEN/NASDA
K. Hattori; I. Takahashi; K. Kawabata; P. Maltsev; M. Hayakawa; V. Korepanve; Y. Kopytenko; O. Molchanve; T. Nagao; S. Uyeda
ibid, 2000
English - Long-term geomagnetic field measurements for earthquake prediction with search-coil magnetometers in Japan
K. Hattori; I. Takahashi; P. Maltsev; Y. Akinaga; M. Hayakawa; K. Yumoto; Y. Kopytenko; V. Korepanve; H. Iwasaki; T. Nagao; S. Uyeda; O. Molchanove
ibid, 2000
English - Modification of low frequency electromagnetic radiation from lightning strokes by conductivity disturbances in lower troposphere
O. A. Molchanov; M. Hayakawa; A. P. Nickolaenko
ibid, 2000
English - NASDA/UEC activity on earthquake signagures on subionospheric VLF/LF propatation
M. Hayakawa; O. A. Molchanov; M. Miyaki; Y. Fukumoto; M. Ishikawa; T. Sawaya
ibid, 2000
English - Seismic effect on the propagation of subionospheric LF radio waves in Italy
Y. Fukumoto; M. Hayakawa; P. F. Biagi
ibid, 2000
English - Ionosphere disturbances possibly related to earthquakes from APEX amd COSMOS-900 data
O. A. Akentieva; V. V. Afonin; O. A. Molchanov; M. Hayakawa
ibid, 2000
English - Anomalous sporadic E ionizations before great earthquakes
T. Ondoh; M. Hayakawa
ibid, 2000
English - Pre-earthquake formation of whistler ducts over the seismic zone
V. M. Sorokin; V. M. Chmyrev; M. Hayakawa
ibid, 2000
English - Penetration of the electrostatic field from the lithosphere and its influence on the ionosphere before earthquakes
V. V. Grimalskiy; M. Hayakawa; V. N. Lvchenko; Yu. G. Rapoport; V. I. Zadoroznii
ibid, 2000
English - Mondragon, Mexico city as aeismic resonator
V. V. Grimalskiy; M. Hayakawa; S. V. Koshvaya; G. N. Burlak; J. Sanchez
ibid, 2000
English - Origin of electromagnetic phenomena accompanied by pre-fracturing deformation in fluid-saturated crust and related seismic observation in Kamchatka
S. Uyeda; M. Hayakawa; O. Molchanov; S. Yunga; V. Gladyshev
ibid, 2000
English - A search for FM earthquake precursors in the ULF/ELF frequency range at Kamchatka peninsula
S. Uyeda; T. Nagao; M. Hayakawa; O. Molchanov; L. Baransky; E. Fedorov; V. Gladychev; Y. Khabazin; O. Pokhotelov; A. Schekotov
ibid, 2000
English - Complex geophysical observations in Kamchatka seismoactive region of Russia
S. Uyea; T. Nagao; K. Hattori; M. Hayakawa; O. Molchanov; V. Gladychev; O. Pokhotelov; L. Baransky; A. Gorbatikov; A. Shekotov; E. Fedorov; Y. Khabazin; S. Andr
ibid, 2000
English - Relationship between statistical characteristics of ULF magnetic fields and seismic phenomena observed at Karimshino site. First results
S. Uyeda; T. Nagao; M. Hayakawa; O. Molchanov; A. Lutikov; G. Kosarev; A. Schekotov; G. Belyaev
ibid, 2000
English - Possible models of ULF seismic emissions
Molchanov, O. A; M. Hayakawa
Invited Talk, ibid, 16, 2000
English - ELF magnetic perturbations in Taiwan earthquake
Ohta, K; N. Watanabe; H. Mizoguchi; K. Umeda; M. Hayakawa
Invited Talk, ibid, 17, 2000
English - Possible influence of gravity waves on ionospheric equatorial anomaly from data of IK-24 satellite
Molchanov; O. A. M. Hayakawa; V. V. Afonin; O. A. Akentieva; F. A. Mareev; V. Y. Trakhtengertz
Invited Talk, ibid, 26, 2000
English - Earthquake related ULF geomagnetic anomalies
Hattori, K; Y. Akinaga; H. Iwasaki; Y. Kopytenko; I. Takahashi; M. Hayakawa; K. Yumoto; T. Nagao; S. Uyeda
ibid, 40, 2000
English - New ULF/ELF measurement in Seikoshi, Izu peninsula, Japan
Hobara, Y; H. Yamaguchi; Y. Akinaga; T. Watanabe; H. C. Koons; J. L. Roeder; M. Hayakawa
ibid, 41, 2000
English - ULF emissions associated with earthquakes
Akinaga, Y; K. Hattori; M. Hayakawa; K. Yumoto
ibid, 42, 2000
English - Reception of over-horizon FM transmitter signals and their association with earthquakes
Fukumoto, Y; M. Hayakawa; H. Yasuda
ibid, 43, 2000
English - Methds for geophysical data processing and the earthquake predicition problems
Troyan, V. N; Hayakawa, M
ibid, 2000
English - Possible earthquake precursors revealed by LF radio-signals
Biagi, P. F; Piccolo, R; Ermini, A; Martellucci, S; Bellecci, C; Hayakawa, M; Kingsley, S. P
ibid, 2000
English - ULF magnetic emission induced by seismic activity due to inductive seismo-electromagnetic effect
Molchanov, O; Kulchitsky, A; Korovkin, N; Hayakawa, M
ibid, 2000
English - Reception of over-horizon FM signals associated with earthquakes
Hayakawa, M; Fukumoto, Y; Yasuda, H
ibid, 2000
English - ULF/ELF emissions observed in Japan possibly associated with Taiwan earthquake
Hayakawa, M; Ohta, K; Umeda, K; Watanabe, N
ibid, 2000
English - Disturbances of the total electron content and geomagnetic field associated with strong earthquakes
Alperovich, L; Naman, S; Wdowinski, S; Hayakawa, M
ibid, 2000
English - Helio-geophysical aspects in the problems of the earthquake prediciton
Smirnova, N; Peterson, TH; Hayakawa, M
ibid, 2000
English - ULF magnetic emissions connected with under sea bottom earthquakes
Ismaguilov, V. S; Kopytenko, Yu. A; Hattori, K; Voronov, P. M; Molochanov, O. A; Hayakawa, M
ibid, 2000
English - The first results of searching of low-frequency magnetic field fluctuation excited by the seismic activity at kamchatka
Chtchekotov, A; Uyeda, S; Hayakawa, M; Molchanov, O; Barnsky, L; Fedorov, E; Gladychev, V; Pokhotelov, O; Beliaev, G; Khabazin, Y; Lutikov, A., Kosare
ibid, 2000
English - Complex geophysical observations in Kamchatka region, some results
Gladychev, V; Uyeda, S; Hayakawa, M; Molchanov, O; Pokhotelov, O; Baransky, L; Gorbatikov, A
ibid, 2000
English - Lithosphere-atmosphere-ionosphere coupling through gravity waves as observed from propagation of VLF subionospheric signals and satellite recordings
Molchanov, O; Hayakawa, M
ibid, 2000
English - Application of wavelet technique to detection of earthquake signatures in the geomagnetic field
Alperovich, L; Zheludev, V; Hayakawa, M
ibid, 2000
English - 地震電磁気現象
早川正士
「地震予知を考えるシンポジウム」基調講演, 関西サイエンス・フォーラム／ 電気学会主催, 2000
Japanese - Long-term periodical variations in global lightning activity deduced from the Schumann resonance monitoring
AP Nickolaenko; R Hayakawa; Y Hobara
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, AMER GEOPHYSICAL UNION, 104, D22, 27585-27591, Nov. 1999, We deduce temporal variations of the level of global lightning activity from the long-term Schumann resonance (SR) monitoring performed at the Tottori observatory (35.5 degrees N, 134.33 degrees E). The continuous analog records of the horizontal magnetic field cover the period from August 1967 to November 1970. The data show that temporal changes of the SR amplitudes vary considerably from day to day. Meanwhile, the regular diurnal and longer-scale variations appear after averaging. We found annual, and semiannual components in variations of global thunderstorm activity between 1967 and 1970. Comparison with the long-term SR records made recently in Europe allows us to demonstrate the similarity and stability of the global thunderstorm variations on a seasonal scale. Simultaneously, it revealed a contribution from winter thunderstorms in the Japan Sea to the Tottori SR records.
Scientific journal, English - Fractal analysis of ULF geomagnetic data associated with the Guam earthquake on August 8, 1993
M Hayakawa; T Ito; N Smirnova
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 26, 18, 2797-2800, Sep. 1999, This paper presents a fractal analysis of the ULF electromagnetic data obtained at Guam observatory during a strong (Ms=8.0) earthquake occurred on August 8, 1993 near the Guam island. We have already reported the presence of seismogenic ULF emissions for this quake (Hayakawa et al., GRL,1996). The chosen period covered four months before and two months after the earthquake. It was found that the spectrum of emissions at noon exhibited a power law behavior f(-beta) which is typical for self-organized critical dynamics. The slope of the spectrum in the noon sector fluctuates in a range from 2.5 to 0.7 with a tendency to gradually decrease during the process of the earthquake preparation. We consider this to be a candidate for a precursory signature. The similar effect was found for the night sector. We suggest that the focal zone was at the critical stage of self-organized criticality process before the quake, related to active microfracturing processes followed by the generation of ULF emissions as we detected.
Scientific journal, English - Correlation between subionospheric VLF signal anomalies and earthquakes（Invited）
Yamamoto, N; M. Hayakawa; O. A. Molchanov
Western Pacific Geophys. Meeting, Taiwan, Jul. 1999
English - VLF signal sounding of upper atmosphere to study seisomoinduced perturbations（review）（Invited）
Hayakawa, M; O. A. Molchanov
Western Pacific Geophys.Meeting, Taiwan, Jul. 1999
English - VLF monitoring of seismic activity for different VLF subionospheric paths
Gufeld, I; M. Hayakawa; A. A. Pozhnoi
Western Pacific Geophys. Meeting, Taiwan, Jul. 1999
English - NASDA's earthquake remote sensing frontier project
Hayakawa, M; O. A. Molchanov; T. Kodama
Western Paxific Geophys. Meeting, Taiwan, Jul. 1999
English - Statistical and case study of ionospheric plasma response to seismic activity: Search for reliable result from satellite observations
Afonin, V. V; O. A. Akentieva; O. A. Molchanov; L. Ya. Tourvinenko; T. Kodama; M. Hayakawa
Western Pacific Geophys. Meeting, Taiwan, Jul. 1999
English - Statistical and case study of ionospheric plasma response to seismic activity: Search for reliable result from satellite observations
Afonin, V. V; O. A. Akentieva; O. A. Molchanov; L. Ya. Tourvinenko; T. Kodama; M. Hayakawa
Western Pacific Geophys. Meeting, Taiwan, Jul. 1999
English - An attempt to trace earthquake precursors at the ionosphere using GPS data
Hirari, M; T. Kodama; M. Hayakawa
Western Pacific Geophys. Meeting, Taiwan, Jul. 1999
English - ULF magnetic emissions associated with 1997 Kagoshima earthquakes
Hattori, K; M. Hayakawa; K. Yumoto; T. Nagao; S. Uyeda
Western Pacific Geophys. Meeting,Taiwan, Jul. 1999
English - Direction of arrival estimation using blind separation of sources
M Hirari; M Hayakawa
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 34, 3, 693-701, May 1999, The estimation of direction of arrival (DOA) and polarization of an incident electromagnetic (EM) wave is of great importance in many applications. Ln this paper we propose a new approach for the estimation of DOA for polarized EM waves using blind separation of sources. In this approach we use a vector sensor, a sensor whose output is a complete set of the EM field components of the irradiating wave, and we reconstruct the waveforms of all the original signals that is, all the EM components of the sources' fields. From the waveform of each source we calculate its amplitude and phase and consequently calculate its DOA and polarization using the field analysis method. The separation of sources is conducted iteratively using a recurrent Hopfield-like single-layer neural network. The simulation results for two sources have been investigated. We have considered coherent and incoherent sources and also the case of varying DOAs vis-(a) over bar-vis the sensor and a varying polarization. These are cases seldom treated by other approaches even though they exist in real-world applications. With the proposed method we have obtained almost on-time tracking for the DOA and polarization of any incident sources with a significant reduction of both memory and computation costs.
Scientific journal, English - ELF sub-ionospheric pulse in time domain
AP Nickolaenko; M Hayakawa; IG Kudintseva; SV Myand; LM Rabinowicz
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 26, 7, 999-1002, Apr. 1999, We present an analytical time domain solution for ELF electromagnetic waves propagating in the Earth-ionosphere cavity. The workability of the formula obtained is demonstrated by computations of the pulse waveforms originating from a point vertical electric source.
Scientific journal, English - 緯度、経度方向の電離層の傾きを考慮したホイスラの3次元レイトレーシング
神崎浩史; 牧田和幸; 田中明博; 太田健次; 早川正士
C, Trans. IEE of Japan, 119-C, 1, 77-82, 1999
Japanese - A model for causative discharge of ELF-transients
A. P. Nickolaenko; M. Hayakawa
J. Atmos. Electr, 19, 1, 11-24, 1999
English - 整合フイルタの概念を用いたトリンピ・イベントの自動検出法
嶋 直樹; 早川正士
J. Atmos. Electr., 19, 1, 61-68, 1999
Japanese - 三次元トレーシングを用いた異なる低緯度におけるホイスラの伝搬解析
太田健次; 嶋 直樹; 神崎浩史; 牧田和幸; 田中明博; 早川正士
J. Atmos. Electr., 19, 1, 69-79, 1999
Japanese - 地震電磁気現象
早川正士
電子情報通信学会誌, The Institute of Electronics, Information and Communication Engineers, 82, 3, 280-282, 1999
Japanese - Development of a complex approach for searching and investigation of electromagnetic precursors of earthquakes : Organization of experiments and analysis procedures in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
V. N. Troyan; N. A. Smirnova; Yu. A. Kopytenko; Th. Peterson; M. Hayakawa
Terra Sci. Pub. Co. , Tokyo, 147-170, 1999
English - On a possibility of parametric amplifier in the stratosphere-mesosphere suggested by active MASSA experiments with the AUREOL-3 satellite in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
Yu. Galperin; M. Hayakawa
Terra Sci. Pub. Co. , Tokyo, 429-437, 1999
English - Long period variations in seismic and electromagnetic measurements in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
A. V. Gorbatikov; T. Kodama; O. A. Molchanov; M. Hayakawa
Terra Sci. Pub. Co. , Tokyo, 439-450, 1999
English - Geometrical model for the VLF precursory signal at the propagation path Tsushima-Inubo before the Kobe earthquake in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
A. P. Nickolaenko; M. Hayakawa; O. A. Molchanov
Terra Sci. Pub. Co. , Tokyo, 451-458, 1999
English - Statistical study of ionospheric plasma response to seismic activity : Search for reliable result from satellite observations in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
V. V. Afonin; O. A. Molchanov; T. Kodama; M. Hayakawa; O. A. Akentieva
Terra Sci. Pub. Co. , Tokyo, 597-617, 1999
English - Anomalous occurrence of sporadic E-layers before the Hyogoken-Nanbu earthquake, M7.2 of January 17,1995 in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
T. Ondoh; M. Hayakawa
Terra Sci. Pub. Co. , Tokyo, 629-639, 1999
English - Influence of acoustic wave on the E-and F-layers of the ionosphere in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
S. Koshevaya; M. Hayakawa; A. Kotsarenko; N. Kotsarenko
Terra Sci. Pub. Co. , Tokyo, 647-653, 1999
English - Analysis of lightning-induced ionization from VLF Trimpi events in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
O. A. Molchanov; A. V. Shvets; M. Hayakawa
Terra Sci. Pub. Co. , Tokyo, 959-988, 1999
English - Analysis of penetration of VLF atmospherics under water using synchronous measurement on the sea surface and in depth in Atmospheric and Ionospheric Electromagnetic Phenomena Associated with Earthquakes
A. V. Shvets; B. V. Lazebny; A. S. Kukushkin; M. Hayakawa
Terra Sci. Pub. Co. , Tokyo, 989-996, 1999
English - Beam-plasma instability in inhomogeneous magnetic field and second order cyclotron resonance effect
V. Y. Trakhtengertz; Y. Hobara; A. G. Demekhov; M. Hayakawa
Phys. Plasma, 6, 692-698, 1999
English - Polarization effects for subionospheric ELF/VLF signals penetrated into the seawater
V. A. Rafalsky; M. Hayakawa; A. V. Shvets
Atoms. Res., 51, 237-244, 1999
English - Anomalous subsurface VLF electric field changes associated with earthquakes and nuclear explosions observed at Agra
B. Sigh; R. P. Singh; V. Bansal; M. Kumar; M. Hayakawa
J. Atmos. Electr, 19, 2, 119-134, 1999
English - ELF-pulse propagation from staircase lightning strokes
A. P. Nickolaenko; M. Hayakawa
J. Atmos. Electr., 19, 2, 135-146, 1999
English - Neural network system for the analysis of transient phenomena on board the Demeter micro-satellite
F. Elie; M. Hayakawa; M. Parrot; J-L Pincon; F. Lefeuvre
IEICE Trans. Fundamentals, E82-A, 8, 1575-1581, 1999
English - Whistler cyclotron instability and second order cyclotron resonance effects in the magnetosphere
V. Y. Trakhtengerts; Y. Hobara; A. G. Demekhov; M. Hayakawa
Adv. Space Res., 24, 1, 35-42, 1999
English - Cyclotron amplification of whistler waves
Y. Hobara; V. Y. Trakhtengerts; A. G. Demekhov; M. Hayakawa
Adv. Space Res., 24, 1, 95-98, 1999
English - Aigorithm for choosing the place for the global schumann resonance observatory
A. P. Nickolaenko; M. Hayakawa
Adv. Polar Upper Atmos. Res., 13, 119-131, 1999
English - Propagation of coupled Rayleigh-gravity waves on the ocean floor
G. N. Burlak; S. V. Koshevaya; M. Hayakawa; J. Sanchez-Mondrago ́n; V. V.Grimalsky
Geof(]E85F1[)sica Internacional, 38, Num.4, 261-268, 1999
English - Formation of electron beams under the interaction of a whistler wave packet with the radiation belt electrons
Y. Hobara; V. Y. Trakhtengerts; A. G. Demekhov; M. Hayakawa
Adv. Space Res., 24, 8, 1007-1010, 1999
English - Self-consistent theory of triggered VLF emissions : an analytical approach
V. Y. Trakhtengerts; Y. Hobara; A. G. Demekhov; M. Hayakawa
Adv. Space. Res., 24, 4, 1011-1014, 1999
English - The modelling of VLF Trimpis using both finite element and 3D Born modelling
K Baba; D Nunn; M Hayakawa
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 25, 24, 4453-4456, Dec. 1998, This paper investigates the numerical modelling of VLF Trimpis produced by a D region inhomogeneity on the Great Circle Path. Two different codes are used. The first is a 2D finite element method (FEM) code, whose solutions are valid in the non-Born limit. The second is a 3D model that invokes the Born approximation. The predicted Trimpis from these codes compare closely, thus confirming the validity of both models. The modal scattering matrices have a comparable structure, and indicate strong scattering between the dominant TM modes. Analysis of the scattering matrix from the FEM code delineates the Born regime. For a LIE with a radius of 100kms, the Born approximation becomes invalid at an electron density perturbation of about 8 el/cc.
Scientific journal, English - Analysis of lightning-induced ionization from VLF Trimpi events
OA Molchanov; AV Shvets; M Hayakawa
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 103, A10, 23443-23458, Oct. 1998, Detailed analysis of Trimpi phenomena (Trimpis) revealed two different regimes in their temporal behavior. One time regime is the initial "nose" part of Trimpis of about 1-5 s, and the second is the "tail" of Trimpis of about 50-100 s. Using a rather simple theoretical model of VLF wave scattering from abating ion and electron density perturbations, we discovered two fitting formulas to describe the temporal evolution of Trimpis. An exponential-hyperbolic evolution in amplitude a/a(0) = (exp{-t/tau(0)})/[1 + b/2(1 - exp{-t/tau(0)})] for weak scattering and a logarithmic dependence a/a(0) = [ln tau(2)/(t + tau(1))]/(ln tau(2)/tau(1)) for strong scattering. Parameters b, tau(0), tau(1), tau(2) were calculated for all the observed 50 Trimpi events. Maximal ion and electron density perturbation (Delta n(mi) and Delta n(me)) were estimated together with the background ion and electron density (n(i0) and n(e0)) and vertical length of the perturbation column (Delta H). For the conventional model of background electron density and horizontal scale of perturbations L similar or equal to 5 - 10 km, we find the perturbation parameters to be as follows: Delta n(me) similar or equal to 10(3) - 10(4) cm(-3), Delta n(me)/n(e0) similar to Delta n(mi)/n(i0) similar or equal to 10 - 100, n(i0) similar or equal to 3 x 10(3) similar or equal to 3 x 10(3) cm(-3), and Delta H similar to 10 - 15 km.
Scientific journal, English - VLF Trimpi modelling on the path NWC-Dunedin using both finite element and 3D Born modelling
D Nunn; K Baba; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 60, 15, 1497-1515, Oct. 1998, This paper investigates the numerical modelling of VLF Trimpis, produced by a D region inhomogeneity on the great circle path. Two different codes are used to model Trimpis on the path NWC-Dunedin. The first is a 2D Finite Element Method Code (FEM), whose solutions are rigorous and valid in the strong scattering or non-Born limit. The second code is a 3D model that invokes the Born approximation. The predicted Trimpis from these codes compare very closely, thus confirming the validity of both models. The modal scattering matrices for both codes are analysed in some detail and are found to have a comparable structure. They indicate strong scattering between the dominant TM modes. Analysis of the scattering matrix from the FEM code shows that departure from linear Born behaviour occurs when the inhomogeneity has a horizontal scale size of about 100 km and a maximum electron density enhancement at 75 km altitude of about 6 electrons. (C) 1998 Elsevier Science Ltd. All rights reserved.
Scientific journal, English - Cyclotron amplification of whistler waves by electron beams in an inhomogeneous magnetic field
Y Hobara; VY Trakhtengerts; AG Demekhov; M Hayakawa
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 103, A9, 20449-20458, Sep. 1998, Cyclotron wave-particle interactions in the case of well-organized distributions of energetic electrons under an inhomogeneous magnetic field are studied. Step-like and delta function distributions over the field-aligned velocity are considered. The one-hop amplification of whistler waves is calculated by simple analytical solution and numerical computation based on strict approach. The strict consideration, taking into account third-order expansion of the spatial dependence of the electron phase with respect to the wave, reveals some new important features of the one-hop amplification Gamma as a function of frequency and electron beam parameters. The main result is that Gamma exhibits a quasi-periodic structure as a function of wave frequency or characteristic electron parallel velocity, remaining always positive in the case of the step-like distribution but being sign alternative for delta-function. Dependence of Gamma on the parameters of energetic electrons such as their total energy: characteristic parallel velocity, position of the injection point in relation to the equator, and dispersion in parallel velocity is discussed.
Scientific journal, English - Natural electromagnetic pulses in the ELF range
AP Nickolaenko; M Hayakawa
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 25, 16, 3103-3106, Aug. 1998, We analyze the propagation of electromagnetic waves in the ELF. We apply the modal solution for the spherical Earth-ionosphere cavity and obtain the time domain fields using the FFT algorithm. The Schumann resonance amplitude over the frequency-distance plane consists of summits and depressions exhibiting separate extended zones. When the source-observer distance is small, the field maximum is found at some hundred hertz. This component rapidly decays with the distance. The time domain ELF pulse travels with a constant velocity and "bounces" from the source antipode. Its width increases along the path due to absorption of the high frequency component. The distance dependence of the pulse amplitude depends on both the geometrical focusing and the high frequency absorption.
Scientific journal, English - On possibility to monitor seismic and volcano activity using satellites
Hayakawa, M; O. A. Molchanov; T. Kodama; T. Tanaka; T. Igarashi
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - The effect of earthquakes on the lower ionosphere as found by subionospheric VLF propagation
Hayakawa, M; O. A. Molchanov
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - Whistler wave hydrodynamic instability and second order cyclotron resonance effects in the magnetosphere（Invited）
Trakhtengerts, V. Y; Y. Hobara; A. G. Demekhov; M. Hayakawa
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - Cyclotron amplification of whistler waves by electron beams in an inhomogeneous magnetic field
Hobara, Y; G. Demekhov; V. Y. Trakhtengerts; M. Hayakawa
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - Formaton of electron beams under cyclotron interaction of a whistler wave packet with radiation belt
Hobara, Y; A. G. Demekhov; V. Y. Trakhtengerts; M. Hayakawa
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - Self-consistent theory of triggered VLF emissions, an analytical approach
Trakhtengerts, V. Y; Y. Hobara; A. G. Demekhov; M. Hayakawa
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - Plasma density variations observed on satellite possibly related to large earthquakies
Molchonov, O. A; M. Hayakawa; V. V. Afonin; O. A. Akentieva; T. Kodma
32nd Scientific Assembly of COSPAR, Nagoya, Jul. 1998
English - Investigation of Short Path Propagation for Possible Earthquake Precursor Detection（Invited）
Dowdwn; R. L; J. B. Brundell; M. Hayakawa; Remote Sensing of VLF using; Absolute Omnipal
Proc. of 1998 Int'l Conf. on Mathematical Methods In Electromagnetic Theory, Kharkov（Ukraine）, 29-34, Jun. 1998
English - Schuman resonance and global lightning activity（Invited）
Nickolaenko, A. P; M. Hayakawa; Y. Hobara
Proc. of 1998 Int'l Conf. On Mathematical Methods In Electromagnetic Theory, Kharkov（Ukraine）, 296-297, Jun. 1998
English - Electric fields from model lightning discharges（Invited）
Niclolaenko, A. P; M. Hayakawa
Int'l Wroclaw Symp on EMC, 553-556, Jun. 1998
English - Mid-latitude multi-path whistlers including a non-ducted whistler（Invited）
Ohta, K; T. Kitagawa; A. Tanaka; M. Hayakawa; R. L. Dowden
Int'l Wroclaw Symp on EMC, 561-565, Jun. 1998
English - Polarisation effects for tweek propagation
AV Shvets; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 60, 4, 461-469, Mar. 1998, Three field component measurements of night-time "tweek" atmospherics had been performed in both northern and southern hemispheres. Multimode analysis of the frequency-time structure of tweeks allowed us to detail the polarisation features of these signals. Effects induced by the oblique Earth's magnetic field are observed in tweeks: the polarisation non-reciprocity for the propagation from East to West and from West to East, and the left-handed polarisation of the tweek tail. The sense of rotation of the horizontal magnetic field vector of tweeks is opposite in the two hemispheres following the direction of the vertical component of the geomagnetic field. Variations of the polarisation sign are observed at the transitional part (between the head and tail of tweeks). The electron density (28 cm(-3) at 88 km altitude) and the steepness of electron density profile in the lower ionosphere have been estimated using the records of tweeks. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
Scientific journal, English - Multi-signal studying of seismo-ionospheric interconnections using VLF OmniPAL receiver
M Hayakawa; OA Molchanov; AV Shvets; N Yamamoto
1998 INTERNATIONAL CONFERENCE ON MATHEMATICAL METHODS IN ELECTROMAGNETIC THEORY, VOLS 1 AND 2, IEEE, 277-278, 1998
International conference proceedings, English - "ニューラルネットワークを用いた人工雑音源を方位測定法"
後藤 薫; M. Hirari; 早川正士
Trans. IEE of Japan, 118-C, 1998
Japanese - "Analyses of the ULF/ELF records performed in a seismo-active region"
A. Nickolaenko; L Rabinowicz; M. Hayakawa
J. Atmos. Electr., 18, 1-10, 1998
English - On the generation mechanism of ULF seismogenic electromagnetic emissions
OA Molchanov; M Hayakawa
PHYSICS OF THE EARTH AND PLANETARY INTERIORS, ELSEVIER SCIENCE BV, 105, 3-4, 201-210, Jan. 1998, Microfracturing electrification is suggested as a possible mechanism for explaining ULF electromagnetic emissions observed before and after the earthquakes. This effect appears as fast fluctuation of microcracks and leads to the origination of wideband electromagnetic noise. This noise dissipates outside the source region and produces ULF emissions on the ground surface with an upper cutoff frequency similar to 1 Hz due to the skin depth attenuation. Each microcurrent results from charge relaxation during microcrack opening and depends on the time of opening and conductivity of the rock medium. The normal size distribution of microcracks, their fast opening and healing (intermittence), and average size progression due to stress corrosion are assumed. Using this model, it is possible to compare these theoretical explanations with the observational results with reference to the intensity, frequency spectrum and temporal development of ULF magnetic field variations. (C) 1998 Elsevier Science B.V.
Scientific journal, English - "Ultra-low-frequency magnetic fields during the Guam earthquake of 8 August 1993 and their interpretation"
R. Kawate; O. A. Molchanov; M. Hawakawa
PhyS. Earth Planet. Inter., 105, 239-248, 1998
English - Precursory effects in the subionospheric VLF signals for the Kobe earthquake
OA Molchanov; M Hayakawa; T Oudoh; E Kawai
PHYSICS OF THE EARTH AND PLANETARY INTERIORS, ELSEVIER SCIENCE BV, 105, 3-4, 239-248, Jan. 1998, The subionospheric VLF Omega signal transmitted from Tsushima, Japan (geographic coordinates: 34 degrees 37'N, 129 degrees 27'E) was continuously received at Inubo (35 degrees 42'N, 140 degrees 52'E). This data was analyzed during an 8-month period centered on the great Hyogo-ken Nambu (Kobe) earthquake, M-g = 7.2 on 17 January 1995, the epicenter located inside of Fresnel zone of the VLF path. To clarify the possible effect, we developed the special TT (terminator time) method of data processing, which was useful for our short VLF path (distance similar to 1000 km). We discovered a statistically significant change of TT characteristics, which began a few days before the main shock and probably continued a few weeks after it as a transient oscillation with period similar to 10 days. By simple modelling, it was shown that TT changes could be caused by the decrease of the VLF reflection height by similar to 2 km. The possible underlying mechanisms of the effect are not defined; however, an increase of the regular electric field due to radon exhalation before the earthquake or an intensification of planetary waves by seismically influenced atmospheric turbulence might be considered. (C) 1998 Elsevier Science B.V.
Scientific journal, English - "Time-and Frequency-domain Coupling Analysis of Field-to-Nonuniform Transmission Lines"
M. Omid; Y. Kami; M. Hayakawa
Chinese J. Electronics, 7, 193-198, 1998
English - "Electric fields produced by lightning discharges"
A. P. Nickolaenko; M. Hayakawa
J. Geophys. Res., 103, D14, 17,175-17,189, 1998
English - "Subionospheric VLF signal perturbations possibly related to earthquakes"
O. A. Molchanov; M. Hayakawa
J. Geophys. Res., 103, A8, 17,489-17,504, 1998
English - "Model electromagneric pulses in the ELF range"
A. P. Nickolaenko; M. Hayakawa
J. Atmos. Electr., 18, 2, 95-110, 1998
English - "中緯度におけるダクト及びノンダクト伝搬のホイスラ"
太田健次; 北川智美; 神崎浩史; 早川正士; R. L. Dowden
J. Atmos. Electr. Japan, 18, 2, 131-138, 1998
Japanese - Interaction of Powerful Electromagnetic Wave with Integrated P-I-N Structures
S. Koshevaya; E. Gutierrez-D; M. Hayakawa; M. Tecpoyotl-T; V. Grimalsky; Y. Kishenko
Jpn. J. Appl. Phys., 37, 4332-4333, 1998
English - Dynamics of Charge Storage and Interaction of Microwaves with Silicon-Integrated Surface Oriented Structures
S. Koshevaya; M. Tecpoyotl; M. Hayakawa; V. Grimalsky; Y. Kishenko
Jpn. J. Appl. Phys., 37, 4334-4335, 1998
English - On a possibility of parametric amplifier in the stratosphere-mesosphere suggested by active MASSA experiments with the AUREOL-3 satellite
Y Galperin; M Hayakawa
EARTH PLANETS AND SPACE, TERRA SCIENTIFIC PUBL CO, 50, 10, 827-832, 1998, A short review is given of the contemporary concepts and controversies concerning the electromagnetic effects observed in space which are considered to be the results of energy transport from surface and/or lower atmosphere. A concept of a parametric amplifier in the stratosphere-mesosphere was recently suggested by the authors (1996) from the reanalysis of the experimental results from the AUREOL-3 satellite during active experiments MASSA with ground chemical explosions. Electric discharges in the stratosphere-mesosphere medium were suggested as a mechanism for this parametric amplifier. Such discharges, or localized electric current bursts in the Alfven wave frequency scale (similar to 0.1-1 s(-1)), could also play a role as a mechanism of effective energy transport from the surface to space layers. Among the possible EQ precursor effects, some can be related to local atmospheric electricity variations such as emanations of gas and/or aerosols, conductivity changes in the lower atmosphere, or non-linear combinations of acoustic waves with a meteor ionization channel. Thus a multidisciplinary search of EQ precursors, especially with regard to atmospheric electricity variations, lightning-type, or slower discharges related to meteor ionization, seems to be among the ways to deepen the understanding of the complicated relations between different layers of atmosphere and magnetosphere.
Scientific journal, English - Characteristics of nearby lightning discharges observed at Singapore
AV Shvets; AP Nickolaenko; M Hayakawa
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 59, 14, 1717-1726, Sep. 1997, An analysis is performed of the parameters of nearby lightning discharges. Vertical electric and two perpendicular horizontal magnetic field components were recorded in the frequency range from 300 Hz to 13 kHz. Observations were performed at Singapore on 26 February, 1991. Data were stored in the 'Elektronika-85' computer memory that worked with a sampling frequency of 100 kHz. The source bearing was obtained using the horizontal components of the Poynting vector. These were calculated from the field components of the pulse signal directly in the time domain. The source distance was also estimated using the phase spectra of the wave impedance. Six events were chosen for the final processing that originated from predominantly vertical strokes observed visually during the data acquisition. Coordinates deduced from the electromagnetic records agree with the Visual observations. Spectra of the current moments of the strokes were calculated from the records after the source distance was established. Experimental results are compared with the model representations for median return stroke. (C) 1997 Elsevier Science Ltd.
Scientific journal, English - Field coupling to nonuniform and uniform transmission lines
M Omid; Y Kami; M Hayakawa
IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 39, 3, 201-211, Aug. 1997, In this paper, we study time-domain and frequency-domain responses of nonuniform and uniform transmission lines excited by incident electromagnetic waves, Externally excited uniform transmission lines permit closed-form solutions in terms of inverse chain matrix, whereas nonuniform lines cannot be analytically solved, in general, Here, we adopt a method of equivalent cascaded network chain as the method of solving the latter situation, Useful and compact expressions for the load currents induced at terminal loads are derived, To confirm the validity of this method and the forcing terms, theoretical and experimental results of coupling calculations for a few typical (uniform/nonuniform) line geometries, relevant in the EMC field, are presented and discussed.
Scientific journal, English - Crosstalk analysis of high-speed logic circuits
M Omid; Y Kami; M Hayakawa
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E80B, 5, 678-685, May 1997, This paper presents a theory based on combined differential- and common-mode propagation for crosstalk and transient analysis of pairs of asymmetric coupled interconnects with arbitrary time-invariant linear termination circuits. Time-domain solutions are obtained by an exact numerical inversion of Laplace transform (NILT). Two example circuits (coupled coplanar stripline and microstrip structures) are studied to examine the accuracy and efficiency of the present method.
Scientific journal, English - On estimating the amplitude of Jovian whistlers observed by Voyager 1 and implications concerning lightning
Y Hobara; S Kanemaru; M Hayakawa; DA Gurnett
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 102, A4, 7115-7125, Apr. 1997, In this paper we extensively reexamine the amplitude of many whistlers detected by the Voyager 1 and try to deduce information about the causative lightning discharges with the use of our ray-tracing computations taking into account the amplitude. As a result; we have derived the frequency spectra and mean radiation power of the causative lightning discharges and have also applied statistical method to the analysis. We can summarize our findings in the following. The average power flux spectral density of the whistlers falls in a range from 10(-12.7)V(2)m(-2)Hz(-1) to 10(-11.0)V(2)m(-2)Hz(-1). We calculated the total decrease of the whistler amplitude from the bottom of the ionosphere toward the spacecraft, as a range from about 30 to 40 dB. One of the strongest estimated lightning events exhibits a frequency dependence comparable to the terrestrial one; but its peak frequency seems to be similar to the upward current strokes on the Earth. Moreover, the rather smooth profile obtained implies a small possibility of the presence of stratified layers in the Jovian ionosphere. Other events possibly have features similar to those of the terrestrial return strokes. We calculated the mean radiation power per flash of the lightning in the Jovian atmosphere for a 1-kHz bandwidth over 60 ms, as a range from the order of 10(2) to 10(5) W. The probability distribution of the radiation power in Jupiter is found to follow a lognormal distribution, just as in the terrestrial case.
Scientific journal, English - An imaging algorithm using the bispectrum in radio interferometry
S Katagiri; KI Morita; N Kawaguchi; M Hayakawa
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, 49, 1, 123-129, Feb. 1997, We present a maximum-entropy imaging algorithm using the bispectrum observed with radio interferometers. It is iterative and based on the steepest-ascent method. Imaging simulation tests show that this algorithm can reconstruct more reliable images of weak, extended sources than can the conventional self-calibration method. An example application of this algorithm to data of the Nobeyama Millimeter Array is given.
Scientific journal, English - Analysis of field coupling to nonuniform transmission Lines
Trans. Inst. Electr. Engrs. of Japan, 117-A, 484-489, 1997
Scientific journal, English - Crosstalk analysis of high-speed logic circuits
Inst. Electr. Inform. Comm. Engrs. Japan, E80-B, 678-685, 1997
Scientific journal, English - Study of Propagation Characteristics of Very Latitude Whistler by Means of Three-dimensional Ray-tracing Computations
J. Geophys. Res., 102, 7537-7546, 1997
English - "3次元レイトレーシングによる超低緯度ホイスラの伝搬特性"
電子情報通信学会論文誌, J80-B, 314-321, 1997
Japanese - "Analysis of Field Coupling to Nonumiform Transmission Lines"
Trans, IEE of Japan, 117-A, 484-489, 1997
English - "中波放送局周辺地域における電磁界強度予測法"
電子情報通信学会論文誌, J80-B-II, 524-532, 1997
Japanese - "A new type of mid-latitude multipath whisrler trains including a non-ducted whistler"
Geophys. Res. Lett., 24, 2937-2740, 1997
English - "VLF電波で地震予知は可能か?"
地震ジャーナル, 24, 29-38, 1997
Japanese - Anomalies in the sub-ionospheric VLF signals for the 1995 Hyogo-ken Nanbu earthquake
M Hayakawa; OA Molchanov; T Ondoh; E Kawai
JOURNAL OF PHYSICS OF THE EARTH, CENTER ACADEMIC PUBL JAPAN, 44, 4, 413-418, 1996, The sub-ionospheric VLF Omega signal transmitted from Tsushima, Japan (geographic coordinates: 34 degrees 37'N, 129 degrees 27'E) is continuously received at Inubo (35 degrees 42'N, 140 degrees 52'E). The signal's propagation characteristics (especially phase) exhibited abnormal behavior (especially around the sunrise and sunset local times) a few days before the main shock of the 1995 Hyogo-ken Nanbu earthquake. We found from the computer simulation of VLF signal propagation that the observed effect can be explained by a decrease of about 0.7 km of VLF reflection height al the atmosphere-ionosphere boundary.
Scientific journal, English - GENERATION OF ULF ELECTROMAGNETIC EMISSIONS BY MICROFRACTURING
OA MOLCHANOV; M HAYAKAWA
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 22, 22, 3091-3094, Nov. 1995, Microfracturing electrification is discussed as a possible explanation of ULF electromagnetic emissions observed before and after earthquakes. Using a space-time simple model of microfracture progression, it is possible to compare theoretical results and observed results with special reference to the intensity, spectrum, and temporal development of ULF magnetic field variations.
Scientific journal, English - THE EFFECT OF LOCALIZED IONOSPHERIC PERTURBATIONS ON SUBIONOSPHERIC VLF PROPAGATION ON THE BASIS OF FINITE-ELEMENT METHOD
K BABA; M HAYAKAWA
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 30, 5, 1511-1517, Sep. 1995, The purpose of this paper is to propose the use of finite element method in investigating the effect of localized perturbations in the lower ionosphere on subionospheric VLF propagation. Due to the complexity of the method, we have analyzed only a two-dimensional case where a localized perturbation lies on the great circle path between the transmitter and receiver. The formulation is first. made, and a few computational results are presented in order to indicate the effectiveness of this finite element, method.
Scientific journal, English - METHOD OF MODELING OF VLF WAVE-PROPAGATION IN THE EARTHS MAGNETOSPHERE AND UPPER IONOSPHERE
OA MOLCHANOV; OA MALTSEVA; M HAYAKAWA; Y HOBARA
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 30, 5, 1597-1611, Sep. 1995, A method of ray tracing (RT) with amplitude variations for simulating VLF wave propagation in a weakly inhomogeneous upper ionosphere and magnetosphere is discussed in detail. This ray tracing plus amplitude (RTA) technique is different from the existing ones in the selection of the most complete model with all its plasma parameters dependent on geomagnetic activity, allowance of thermal correction to the refractive index, and calculations of amplitude factors (coefficients of focusing-defocusing, polarization, and linear amplification-attenuation). The presented examples of calculations show that the introduction of the above new elements in the RT technique makes it possible to clarify the wave propagation properties and to account for numerous experimental phenomena.
Scientific journal, English - ASSOCIATION OF WHISTLERS WITH LIGHTNING DISCHARGES ON THE EARTH AND ON JUPITER
M HAYAKAWA
JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 57, 5, 525-535, Apr. 1995, The association between whistlers and lightning discharges has been reviewed on the basis of terrestrial ionospheric satellite observations of VLF radio noise. Evidence indicating that the observed low-latitude radio noise is associated with thunderstorms includes (1) amplitude distribution and noise properties, (2) geographical location, (3) diurnal variation in activity, and (4) diurnal variation of frequency spectrum. Corresponding studies on the propagation of sferics in the ionosphere and the excitation of whistlers recently carried out for Jupiter are presented here and compared with the terrestrial studies.
Scientific journal, English - PENETRATION CHARACTERISTICS OF ELECTROMAGNETIC EMISSIONS FROM AN UNDERGROUND SEISMIC SOURCE INTO THE ATMOSPHERE, IONOSPHERE, AND MAGNETOSPHERE
OA MOLCHANOV; M HAYAKAWA; VA RAFALSKY
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 100, A2, 1691-1712, Feb. 1995, Theoretical calculations are made on electromagnetic fields in the frequency range 10(-2) to 10(2) Hz on the ground surface and above the ionosphere induced by stochastic microcurrent activity inside the future seismic sources on the assumption of cylindrical symmetry of the effective current and three types of polarization. The inhomogeneity of the ground and atmosphere conductivity and anisotropy of the ionosphere are taken into consideration. The intensity of ULF magnetic and electric precursors observed on the ground, and their spatial distribution can be explained by using the results of the present computations. It is found that only the fields from a magnetic type source can penetrate into the magnetosphere and generate propagating Alfven waves. The expected values of magnetospheric electric and magnetic field are 1-10 mu V m(-1) Hz-(1/2) and 1-10 pT Hz-1/2 respectively, and the horizontal scale of their distribution is about 100-200 km. Finally, these theoretical predictions are compared with the corresponding results of satellite observations.
Scientific journal, English - Location of lightning disch arges from a single station
J. of Geophysical Res., 100, 20829-838, 1995
Scientific journal, English - GCV-aided linear reconstraction of the wave didtribution function for the ground-based direction finding of magnetospheic VLF/ELT waves
J. Electromagnetic Wavesd Applocation, 9, 757-782, 1995
English - Heating of the lower ionosphere electrons by electromapnetic radiation of lightning discharges
Geophys, Res, Letty, 22, 3015-18, 1995
English - THE EFFECT OF SUBIONOSPHERIC PROPAGATION ON WHISTLERS AS DEDUCED FROM DIRECTION FINDING MEASUREMENTS
K OHTA; A SHIMIZU; M HAYAKAWA
GEOPHYSICAL RESEARCH LETTERS, AMER GEOPHYSICAL UNION, 21, 2, 89-92, Jan. 1994, The characteristics of subionospheric propagation of magnetospheric whistlers have been investigated by means of both digital spectral analysis with high resolution and our field-analysis direction finding measurement for whistlers observed in South China. It is found that very low latitude whistlers, propagated in the Earth-ionosphere waveguide over a distance of the order of 1000km, exhibit very clear additional dispersion effects near the cutoff frequencies of the subionospheric 1st- and higher- order modes. The additional traces are also found to be left-handed polarized, and when the frequency approaches the cutoff frequencies, the wave polarization becomes very close to exactly left-handed circular and the incident angle becomes nearly vertical. While, the whistler components at frequencies away from the cutoff frequencies are linearly polarized. Finally, we emphasize the important use of the subionospheric propagation characteristics in the study of the whistler duct structure, ionospheric transmission of a downgoing whistler and its excitation of subionospheric modes.
Scientific journal, English - Periodic and quasi-periodic VLF/ELF emissions : A review,
J. Atmos. Terr. Phys., 56, 735-753, 1994
Scientific journal, English - On wave characteristics of tweek at mospherics based on direction finding measurement,
HAYAKAWA M.
J. Geophys. Res. ,, 99, 10733-10743,, 1994
Scientific journal, English - Excitation of electromagnetic waves by delta function current sheets in the ionospheric plasma,
Radio Sci. ,, 29, 867-877,, 1994
Scientific journal, English - The effect of subionospheric propagation on whistlers as deduced from direction finding measurements,
Geophys. Res. Lett. ,, 21, 89-92,, 1994
Scientific journal, English - Consideration of dynamic spectra and direction finding results of hiss-triggered chorus emissions,
HATTORI K.
Proc. NIPR Symp. on Upper Atmos. Phys. ,, 7, 40-52,, 1994
Scientific journal, English - A time domain direction finding technique for locating wideband ELF-VLF atmospherics,
J. Atmos. Electr., 14, 97-107,, 1994
Scientific journal, English - A WAVE-WAVE INTERACTION IN WHISTLER FREQUENCY-RANGE IN-SPACE PLASMA
VY TRAKHTENGERTS; M HAYAKAWA
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, AMER GEOPHYSICAL UNION, 98, A11, 19205-19217, Nov. 1993, The quantitative theory is developed for the frequency spectrum broadening and sideband structure of VLF signals in the upper ionosphere. The theory is based on a common theory of wave-wave interaction in plasma and includes the transformation effects of a quasi-monochromatic whistler wave into quasi-electrostatic whistler mode waves (l waves) near the resonance cone with their interaction with field-aligned plasma density (electric field) inhomogeneities. Such inhomogeneities can be ion-acoustic or ion cyclotron electrostatic waves. We consider both cases of regular (deterministic plases) and irregular (random phases) inhomogeneities. The spectral characteristics and interaction length of l waves and some nonstationary effects are considered, which permit us to obtain the quantitative interpretation of main experimental data. The conditions of high coherence of interacting waves are investigated, which are compared with the results of bicoherence analysis of sideband structure of VLF signals. The estimations of bicoherence value are given for such type of wave-wave interaction.
Scientific journal, English - ON THE POSSIBLE INFLUENCE OF SEISMIC ACTIVITY ON THE PROPAGATION OF MAGNETOSPHERIC WHISTLERS AT LOW LATITUDES
M HAYAKAWA; T YOSHINO; VA MORGOUNOV
PHYSICS OF THE EARTH AND PLANETARY INTERIORS, ELSEVIER SCIENCE BV, 77, 1-2, 97-108, Apr. 1993, The purpose of this paper is to ''amine the possible seismic influence on the propagation of magnetospheric whistlers at low latitudes on the basis of long-term data observed at Sugadaira (geomagnetic latitude 25-degrees-N) during 1970-1978 and at Sakushima (24-degrees) during 1980-1982. It is found from statistical analysis of the Sugadaira data that anomalous whistlers whose dispersion value is greater than twice the typical value, exhibit a substantial increase in occurrence during seismic activity in the geographic longitude sector of 100-degrees-E-160-degrees-E, and this association becomes more enhanced when we take the occurrence of any whistlers (short, long and/or anomalous) during the summer time (June-August). Finally, with increasing anomaly (that is, anomalous dispersions and summertime), we have found an exceedingly high statistical correlation between the summertime anomalous whistlers at Sakushima and the seismic activity satisfying the above condition. We have studied whistler characteristics for all earthquakes. These studies have indicated that a considerable number of cases of earthquakes are of a type such that several earthquakes occur successively; and, correspondingly, we observed an enhanced occurrence of anomalous whistlers during such prolonged seismic activities. Several isolated and intense earthquakes are characterized by the appearance of anomalous whistlers prior to and after the earthquake. In conclusion, we claim that whistlers with anomalous dispersions are likely to be closely correlated with earthquakes occurring in the relevant longitude range, but we cannot make any definite statement on the use of low-latitude whistlers as precursors of earthquakes and further detailed studies are obviously required on this subject. Some possible mechanisms of the earthquake-associated effect causing whistler propagation are discussed.
Scientific journal, English - Ground-based Direction Finding of Space Plasma Waves and Its Application
電子情報通信学会誌, 76, 258-264, 1993
Scientific journal, English - Transmission characteristics of VLF/ELF radio waves through the Jovian ionosphere
Geophysical Research Letters, 20, 2, 2435-2438, 1993
Scientific journal, English - 磁気圏VLF/ELF電磁波動分布関数の線形再構成による新地上方位測定法
電子情報通信学会論文誌B-II, J76-8-2, 11, 880-889, 1993
Scientific journal, Japanese - Ionospheric and magnetospheric radio noises at lower latitudes,
Trends in Geophys. Res. ,, 2, 211-231,, 1993
Scientific journal, English - MAGNETOSPHERIC CHORUS EMISSIONS - A REVIEW
SS SAZHIN; M HAYAKAWA
PLANETARY AND SPACE SCIENCE, PERGAMON-ELSEVIER SCIENCE LTD, 40, 5, 681-697, May 1992, Peer-reviwed, A review of chorus emissions observed on ground-based stations and in the Earth's magnetosphere is presented. Different approaches to modelling these emissions are discussed. It is pointed out that the most likely energy source of chorus emissions lies in the anisotropic hot electrons in the equatorial magnetosphere. The energy of these electrons is transferred to waves via the electron cyclotron instability. Then the non-linear deformation of the hot electron distribution function under the influence of these waves produces almost monochromatic wavelets which, in their turn, generate a chorus element in a manner similar to the generation of artificially stimulated emissions by ground-based transmitters.
Scientific journal, English - Whistler Diagnostics of Magnetospheric Parameters : A Review
Sazhin S. S; M. Hayakawa; K. Bullough
Annales Geophysicae, 10, 293-308, 1992, Peer-reviwed
Scientific journal, English - Spaced direction finding of very low latitude whistlers and their propagation mechanism
Journal of Geophysical Research, 95, 1990
Scientific journal, English - Frequency dependence of arrival direction and polarization of low latitude whistlers and their ducted propagation
Journal of Geophysical Research, 94, 1989
Scientific journal, English - Substorm-associated vlf emissions with frequency drift observed in the premidnight sector
Journal of Geophysical Research, 93, 1988
Scientific journal, English - Spectral broadening of vlf transmitter signals and sideband structure observed on Aureole 3 satellite at middle latitudes
Journal of Geophysical Research, 92, 1987
Scientific journal, English - On the generation of quasi-electrostatic half-gyrofrequency whistler mode waves in the magnetospheric plasma
Journal of Plasma Physics, 35, 1986
Scientific journal, English - The wave normals of elf hiss emissions observed on board GEOS 1 at the equatorial and off-equatorial regions of the plasmasphere
Journal of Geophysical Research, 91, 1986
Scientific journal, English - Morphological characteristics and the polarization of plasmaspheric hiss observed at Moshiri (L=1.6)
Journal of Geophysical Research, 90, 1985
Scientific journal, English
MISC
- 「地震電磁気研究ステーション」の活動について
早川正士
This report is intended to provide you with the general activity report of Research Station onSeismo Electromagnetics. First of all, we indicate the importance of seismogenic phenomena in theshort-term earthquake prediction. Then, we show some more details on our activity:(1)International conferences, (2)Domestic seminars, (3)Relation with international and domesticacademic societies, (4)Relation with social societies, and (5)International and domesticcollaborative works., 電気通信大学, 2006, 電気通信大学紀要, 19, 1, 211-215, Japanese, Peer-reviwed, Introduction other, 0915-0935, 120006315659, AN10016842 - 雷・電離層放電に伴う中間圏の発光現象と関連現象
早川正士; 大津山卓哉; 芳原容英; 中村貴弘
2002, 応用光学, 1月, 14-21, Japanese, Introduction other - ＶＬＦ／ＬＦ電離層・大地導波菅伝搬波を用いた地震に伴う電離層擾乱の検出
早川正士
2001, 応用光学, 11月, 24-30, Japanese, Introduction other
Books and other publications
- Special Issue on Recent Progress in Electromagnetic Theory and Its Application
Hayakawa, M; M. Matsumoto; Y. Yamasaki
English, Editor, Inst. Electr. Engrs. Japan, 2004 - Inverse Geophysical Problems
Troyan, V; M. Hayakawa
English, TERRAPUB, Tokyo, 2002 - Seismo Electromagnetics (Lithosphere-Atmosphere-Ionosphere Coupling)
M.Hayakawa; O.A.Molchanov
English, Editor, TERRAPUB, 2002 - Resonances in the Earth-Ionosphere Cavity
MASASHI HAYAKAWA
English, Kluwer Acad. Pub., 2002 - Atmospheric and Ionospheric Electromagnetic Rhenomena Associated with Earthywakes
English, Terra Scientific Rub. Comp., 1999 - Electromagnetic Plenomena Related to Earthquake Prediction,
English, Terra Sci. Pub. Comp. ,, 1994 - EElectrimagnetio Phenomena Related to Eorthquake Prediction Editors M. Hayakawa and Y. Fujinawa
English, Terra Sei. Pub Company, Tokyo, 1994 - Musical Sounds from Space -Space Plasma Waves
English, コロナ社, 1993 - Electromagnetic Wave Engineering
早川正士
English, コロナ社, 1992
Lectures, oral presentations, etc.
- Space Weather and Seismo-Electromagnetics
K. Yumoto; S. Ikemoto; M.G. Cardinal; T. Uozumi; S. Abe; G. Maeda; M. Hayakawa; K. Hattori; K. Shiokawa; J. Y. Liu; M. Ruhimat; S. Saroso; M. Husni; D. S. Widarto; D. McNamara; E.G. Ramos; R. E; S. Otadoy; ND MAGDAS Group
Invited oral presentation, English, Int'l Workshop on Space and Lithosphere Environment Changes in Asia, Int'l Workshop on Space and Lithosphere Environment Changes in Asia, International conference
Mar. 2008 - Some results of seismo-electromagnetic research at LAPAN, Indonesia
S. Saroso; K. Hattori; M. Hayakawa; K. Shiokawa; K. Yumoto; J. Y. Liu
Keynote oral presentation, English, Int'l Workshop on Space and Lithosphere Environment Changes in Asia, Int'l Workshop on Space and Lithosphere Environment Changes in Asia, International conference
Mar. 2008 - Ground-based Electromagnetic Monitoring in the Western Sunda Arc, Indonesia: Recent Progress and Some Results
Djedi S. Widarto; Katsumi Hattori; Febty Febriani; Hendri Subakti; Masturyono; Kenji Ohta; Masashi Hayakawa; Seiya Uyeda
Invited oral presentation, English, Int'l Workshop on Space and Lithosphere Environment Changes in Asia, Int'l Workshop on Space and Lithosphere Environment Changes in Asia, International conference
Mar. 2008 - Review on NASDA's Earthquake Remote Sensing Frontier Project
M. Hayakawa
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetic Observation Satellite, Int'l Workshop on Seismo-Electromagnetic Observation Satellite, International conference
Feb. 2008 - DEMETER衛星を用いた地震に伴う電離層擾乱解析及び擾乱に伴うVLF帯電離層透過減衰の数値計算
武藤史弥; 吉田麻里; 堀江匠; 早川正士; Michel Parrot; O.A.Molchanov
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 中国のULF帯磁場データを用いた地震に関連する以上の検出
伊田裕一; Q. Li; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 光学及び電磁波観測による中間圏発光現象の研究
松戸悠; 明慶健一; 鈴木智幸; 浅野智計; 関口美菜子; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - Computer simulation on mesospheric optical emissions (sprites).
浅野智計; 早川正士; Mengu Cho
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 冬季雷に伴うレッドスプライトの形状の統計
明慶健一; 松戸悠; 浅野智計; 山下幸三; 関口美菜子; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 大気重力波による電離層擾乱シミュレーション
堀江匠; E.A. Mareev; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - Monte Carlo法を用いた太陽フレアによる電離層擾乱の計算
吉田麻里; 田中康之; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - ELF帯電磁波を用いた世界雷放電分布とその正確性の検証
山下幸三; 芳原容英; 大津山卓哉; 関口美菜子; 松戸悠; A.P. Nickolaenko; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - Seismo-Electromagnetics Observation and Data Integration
服部克己; 西橋政秀; 吉野千恵; 湯元清文; 早川正士; 劉正彦; D. Widarto; S. Saroso; Husni
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - Fractal analysis of Japan ULF EM data related to strong seismic events.
Mezentsev Andrew; 早川正士; 伊田裕一; Smirnova Natalia
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 水文水質データベースの欠測状況と地震との関連
長本裕樹; 伊田裕一; 早川正士; 福島毅
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 既存ELF帯電波の伝搬に関する考察
矢野超己; 山下幸三; 関口美菜子; 伊田裕一; 堀江匠; 早川正士; A.P.Nickolaenko
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - シューマン共振パラメタの観測結果と計算結果の比較
関口美菜子; 山下幸三; A. P. Nickolaenko; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - Superimposed epoch analysisを用いたVLFデータ（電離層擾乱）に対する統計的解析
笠原康詩; 堀江匠; 吉田麻里; 武藤史弥; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 干渉計システムを用いた見通し外VHF帯電波の観測とその解析結果
安田好広; 後藤剛芳; 伊田裕一; 米内口直之; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - Ionospheric Alfven Resonance (IAR)の観測とその解析
平岡六太郎; 関口美菜子; 山下幸三; 松戸悠; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第78回研究発表会
Jan. 2008 - 宮城県沖地震に関連したVHF電磁雑音のフラクタル解析
米内口直之; 増田茂; 伊田裕一; 早川正士
Oral presentation, Japanese, 電子情報通信学会技術研究報告、アンテナ・伝搬研究会
Dec. 2007 - 地震に先行した見通し外VHF帯電波の干渉計による測定
安田好広; 後藤剛芳; 伊田裕一; 米内口直之; 早川正士
Oral presentation, Japanese, 電子情報通信学会技術研究報告、アンテナ・伝搬研究会
Nov. 2007 - Interaction of unstable modes of ionospheric plasma and modes of neutral atmosphere
Yu. G. Rapoport; M. Hayakawa; O. E. Gorynyan; V. M. Ivchenko; A. K. Fedorenko; Yu. A. Selivanov
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Indonesia, International conference
Nov. 2007 - Electromagnetic monitoring for crustal activity in Indonesia
K. Hattori; D. S. Widarto; S. Saroso; M. Nishihashi; C. Yoshino; D. Kaida; E. Z. Gaffar; Y. Sudrajat; K. Yumoto; M. Husni; H. Subakti; K. Shiokawa; M. Hayakawa
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Indonesia, International conference
Nov. 2007 - Seismo-electromagnetic signatures possibly related to the Sumatra megathrust earthquakes of 26 December 2004 and 28 March 2005
Sarmoko Saroso; K. Hattori; M. Hayakawa; K. Shiokawa; K. Yumoto
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Indonesia, International conference
Nov. 2007 - Space Weather and Seismo-Electromagnetics
K.Yumoto; H. Kawano; A. Yoshikawa; S. Ikemoto; G. Maeda; M. Hayakawa; K. Hattori; Tiger Liu; S. Saroso; M. Husni; D. Widarto; E. G. Ramos; C. M; G. Cardinal; R. E; S. Otadoy; MAGDAS GRoup
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Indonesia, International conference
Nov. 2007 - Seismo-Electromagnetics: Review
M. Hayakawa
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Int'l Workshop on Seismo-Electromagnetic Phenomena (IWSEP 2007), Indonesia, International conference
Nov. 2007 - DEMETER衛星を用いた地震に伴う電離層擾乱の検出
武藤史弥; 吉田麻里; 堀江匠; 早川正士; Michel Parrot
Oral presentation, Japanese, 電子情報通信学会技術研究報告、アンテナ・伝搬研究会
Sep. 2007 - Seismo-Electromagnetic phenomena in ULF/ELF band associated with the 2004 Sumatra earthquake
Katsumi Hattori; Masahide Nishihashi; Djedi Widarto; Sarmoko Saroso; Kiyohumi Yumoto; Masashi Hayakawa
Invited oral presentation, Japanese, 平成19年電気学会基礎・材料・共通部門大会, 電気学会
Aug. 2007 - Structure and dynamics of ionospheric perturbations associated with the Sumatra earthquake in December, 2004: Ground and satellite observation of VLF transmitter signals
M. Hayakawa; T. Horie; T. Yamauchi; O. A. Molchanov; M. Parrot
Invited oral presentation, English, AOGS 2007, AOGS, Bangkok, Thailand, International conference
Jul. 2007 - Precursory phenomena using ULF electromagnetic wave in possible association with huge earthquakes
K. Ohta; J. Izutsu; N. Watanabe; M. Hayakawa
Invited oral presentation, English, AOGS 2007, AOGS, Bangkok, Thailand, International conference
Jul. 2007 - Direction Finding of ULF/ELF Magnetic Phenomena Preceding the 2004 Sumatra-Andaman Earthquake
K. Hattori; M. Katoh; A. Sazarashi; C. Yoshino
Invited oral presentation, English, AOGS 2007, AOGS, Bangkok, Thailand, International conference
Jul. 2007 - Seismo Electromagnetics: Review
M. Hayakawa
Invited oral presentation, English, Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, Bilateral Seminar Italy-Japan on Electromagnetics in Seismic and Volcanic Area, Chiba, Japan, International conference
Jul. 2007 - 北関東の夏季雷雲観測速報（SKaTE 2007)
道本光一郎; 鈴木智幸; 宮崎忠臣; 岡田富男; 柚研一; 早川正士; 市山尚; 木村順一; 早川信一
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - 地震前兆現象としてのSchumann共振の励起
太田健次; 井筒潤; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - ULF帯電磁波の放射と地震
石野博一; 太田健次; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - インドネシアスマトラ地震に対する前兆電離層擾乱の諸特性（地上VLF観測と衛星観測）
早川正士; 堀江匠; M. Parrot
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - 地震に伴うVHF放射のフラクタル的特性の解明
米内口直之; 増田茂; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - 北陸スプライト形状の月別変化とその解釈
早川正士; 明慶健一; 浅野智計; 鈴木智之
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - シューマン共振の日変化・季節変化 -fitting-
関口美菜子; 山下幸三; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第77回研究発表会
Jul. 2007 - Observation of an ionospheric disturbance coused by an SGR giant flare: Constraints on an energy spectrum of the flare
Yasuyuki Tanaka; Toshio Terasawa; Masashi Hayakawa; Mari Yoshida; Takumi Horie
Oral presentation, Japanese, 日本地球惑星科学連合2007年大会予稿集,日本地球惑星科学連合2007年大会
May 2007 - A study on DC/ULF electromagnetic waves possibly associated with large earthquakes observed at Nakatsugawa
Jun Izutsu; Kenji Ohta; Masashi Hayakawa
Oral presentation, Japanese, 日本地球惑星科学連合2007年大会予稿集,日本地球惑星科学連合2007年大会
May 2007 - Detection of seismo-ionospheric perturbations on basis of reception of VLF transmitter signals on the satellite, DEMETER.
Fumiya Muto; Mari Yoshida; Takumi Horie; Masashi Hayakawa
Oral presentation, Japanese, 日本地球惑星科学連合2007年大会予稿集,日本地球惑星科学連合2007年大会
May 2007 - observation of ionospheric perturbations associated with earthquakes (statistical and case studies)
Masashi Hayakawa; Takumi Horie; Ken Yamauchi; Shinko Maekawa; Mari Yoshida
Invited oral presentation, Japanese, 日本地球惑星科学連合2007年大会, 日本地球惑星科学連合2007年大会予稿集
May 2007 - Fractal analysis of VHF electromagnetic noise associated with the Miyagi prefecture offshore earthquake
Naoyuki Yonaiguchi; Yuichi Ida; Masashi Hayakawa
Oral presentation, Japanese, 日本地球惑星科学連合2007年大会予稿集,日本地球惑星科学連合2007年大会
May 2007 - Global lightning distribution by means of ELF transients observed at Moshiri, Japan
Kozo Yamashita; Takuya Otsuyama; Yasuhide Hobara; Minako Sekiguchi; Yu Matsudo; Masashi Hayakawa
Oral presentation, Japanese, 日本地球惑星科学連合2007年大会予稿集,日本地球惑星科学連合2007年大会
May 2007 - ES/EM computer simulation of the mesospheric optical emission for Japanese summer and winter lightning
Tomokazu Asano; Masashi Hayakawa; Mengu Cho
Oral presentation, Japanese, 日本地球惑星科学連合2007年大会予稿集,日本地球惑星科学連合2007年大会
May 2007 - Decreases in the electric intensity of VLF radio signals and possible connections with the seismicity
Biagi, P.F; Castellana, L; Maggipinto, T; Piccolo, R; Minafra, A; Ermini, A; Capozzi, V; Solovieva, M; Molchanov, O; Hayakawa, M
Invited oral presentation, English, EGU General Assembly 2007, EGU (European Geosciences Union), Vienna, Austria, International conference
Apr. 2007 - ULF/ELF magnetic field variations in atmosphere probably induced by seismicity
Schekotov, A; Molchanov, O; Fedorov, E; Chebrov, V; Sinitsin, V; Gordeev, E; Belyaev, G; Hayakawa, M
Invited oral presentation, English, EGU General Assembly 2007, EGU (European Geosciences Union), Vienna, Austria, International conference
Apr. 2007 - Magnetic location of ionosphere and lithosphere sources of ULF geomagnetic disturbances
Kopytenko, Yu; Ismaguilov, V; Hattory, K; Hayakawa, M
Invited oral presentation, English, EGU General Assembly 2007, EGU (European Geosciences Union), Vienna, Austria, International conference
Apr. 2007 - Extraction of the earthquake precursory signatures from fractal characteristics of ULF emissions
Smirnova, N; Hayakawa, M; Uritsky, V; Mezentsev, A
Invited oral presentation, English, EGU General Assembly 2007, EGU (European Geosciences Union), Vienna, Austria, International conference
Apr. 2007 - Mesoscale lightning in west African squall lines and its global detection with ELF measurements
Hobara, Y; Williams, E; Boldi, R; Satori, G; Bor, J; Lyons, W; Nelson, T; Hayakawa, M; Nathou, N; Russell, B
Invited oral presentation, English, EGU General Assembly 2007, EGU (European Geosciences Union), Vienna, Austria, International conference
Apr. 2007 - 冬季雷（北陸および太平洋）に伴うスプライトの多点観測
明慶健一; 松戸悠; 山下幸三; 浅野智計; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 冬季スプライトの発生位置と雷放電
鈴木智幸; 松戸悠; 早川正士; 道本光一郎
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 日本の夏季、冬季雷に伴う中間圏発光現象に伴う計算機シュミレーション
浅野智計; 早川正士; MENGU CHO
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 中間圏発光現象に伴う下部電離層擾乱の研究
松戸悠; 明慶健一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 夏季北関東の雷雲観測（SKaTE2006）速報
宮崎忠臣; 岡田富男; 鈴木智幸; 道本光一郎; 早川正士; 橋口博之; 大東雄二; 市山尚; 木村順一; 早川信一
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 日本でのシューマン共振の日変化・季節変化
関口美菜子; 山下幸三; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 見通し外VHF波電波伝搬と気象擾乱との関連
中西崇之; 米内口直之; 安田好弘; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 地震に伴うVHF放射のフラクタル解析
米内口直之; 増田茂; 伊田裕一; 安田好弘; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - Superimposed epoch analysisを用いた地震に伴うVLF/LFターミネータタイムの変動解析
西戸久美; 山内健; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - Wave-hop法およびモード理論を用いたVLF/LF電波伝搬解析
吉田麻里; 山内健; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 地震に伴う電離層擾乱：静電界効果のシミュレーション
山内健; 堀江匠; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - スマトラ地震に伴う電離層擾乱の諸特性（地上及び衛星観測に基づく）
早川正士; 堀江匠; 山内健; Molchanov O. A; Rozhnoi A. A; Solovieva M
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - スマトラ沖地震に伴う下部電離層擾乱の研究
堀江匠; 山内健; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 衛星DEMETERを用いた地震に伴う電離層擾乱の検出
武藤史弥; 吉田麻里; 堀江匠; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 八木アンテナを用いた干渉計システムの構築
安田好弘; 後藤剛芳; 米内口直之; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 地震に伴うULF帯電磁波の方位測定
矢野超己; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - 地震に関連したULF帯電磁放射の到来方向測定
伊田裕一; 矢野超己; 早川正士; 太田健次
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - ULF帯磁場データに対するマルチフラクタル解析
横瀬史拓; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - ELF transientsを用いた世界雷放電分布の導出
山下幸三; 大津山卓哉; 芳原容英; 関口美菜子; 松戸悠; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第76回研究発表会
Jan. 2007 - Seismo-electromagnetic phenomena: Recent results
M. Hayakawa
Invited oral presentation, English, IWEMSEV-2006 (International Workshop on Electromagnetic Studies Related to Earthquakes and Volcanoes), IWEMSEV (International Workshop on Electromagnetic Studies Related to Earthquakes and Volcanoes), Agra, India, International conference
Nov. 2006 - Electromagnetic Phenomena Associated with Earthquakes: Review
M. Hayakawa
Invited oral presentation, English, PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, PIERS (Progress In Electromagnetics Resarch Symposium), Tokyo, Japan, International conference
Aug. 2006 - Anomalous Effect in Schumann Resonance Phenomena Observed in Japan, Possibly Associated with the Earthquakes in Taiwan
M. Hayakawa; K. Ohta
Invited oral presentation, English, PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, PIERS (Progress In Electromagnetics Resarch Symposium), Tokyo, Japan, International conference
Aug. 2006 - The Observation of DC/ULF Emissions at Nakatsugawa, Japan in Possible Association with the Niigata-Chuetsu Earthquake
K. Ohta; N. Watanabe; M. Hayakawa
Invited oral presentation, English, PIERS (Progress In Electromagnetics Resarch Symposium) 2006-Tokyo, PIERS (Progress In Electromagnetics Resarch Symposium), Tokyo, Japan, International conference
Aug. 2006 - The Observation of DC/ULF Emission at Nakatsugawa, Japan in Possible Association with the Sumatra-Andaman Earthquake
K. Ohta; N. Watanabe; M. Hayakawa
Invited oral presentation, English, Asia Oceania Geosciences Society 3rd Annual Meeting 2006, Asia Oceania Geosciences Society, Singapore, International conference
Jul. 2006 - Anomalous Effect in Schumann Resonance Phenomena Observed in Japan, Poxxibly Associated with the Earthquakes in Taiwan
M. Hayakawa; K. Ohta; A. P. Nickolaenko
Invited oral presentation, English, Asia Oceania Geosciences Society 3rd Annual Meeting 2006, Asia Oceania Geosciences Society, Singapore, International conference
Jul. 2006 - DC/ULF帯電磁波に現れる超遠方地震の前兆現象
石野博一; 太田健次; 渡邉伸夫; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第75回研究発表会
Jul. 2006 - インドネシアにおける地震電磁気観測
服部克巳; 西橋政秀; 湯元清文; 早川正士; Djedi Widarto; Sarmoko Saroso
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第75回研究発表会
Jul. 2006 - 見通し外VHF伝搬の気象現象及び地震との関係
米内口直之; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第75回研究発表会
Jul. 2006 - インドネシアスマトラ地震に伴う電離層擾乱の観測（DEMETER衛星観測を中心として）
早川正士; O.A.Molchanov; 堀江匠
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第75回研究発表会
Jul. 2006 - スマトラ地震に伴う電離層擾乱の検出とそのダイナミクスの検出
堀江匠; 山内健; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第75回研究発表会
Jul. 2006 - ULF Magnetic Variations Produced by the Underground Nuclear Blasts
L. Alperovich; M. Hayakawa; G. Aburjania; A Khantadze; E. Morozov
Invited oral presentation, English, Asia Oceania Geosciences Society 3rd Annual Meeting 2006, Asia Oceania Geosciences Society, Singapore, International conference
Jul. 2006 - 地震電磁気現象の衛星観測
早川正士
Oral presentation, Japanese, 第4回宇宙ミッションシンポジウム－安全・安心に役立つ宇宙ミッション－,第4回宇宙ミッションシンポジウム－安全・安心に役立つ宇宙ミッション－
Jul. 2006 - インドネシア・スマトラ沖地震に伴う電離層擾乱の検出
堀江匠; 前川慎光; 早川正士
Oral presentation, Japanese, 電気学会,電気学会電磁環境研究会
Jun. 2006 - 新潟中越地震に伴う電離層擾乱の空間的ダイナミクスの研究
山内健; 前川慎光; 早川正士
Oral presentation, Japanese, 電気学会,電気学会電磁環境研究会
Jun. 2006 - インドネシアにおける地震電磁気観測
服部克巳; Djedi Widarto; Sarmoko Saroso; Nugroho Hananto; 湯元清文; 早川正士
Oral presentation, Japanese, 電気学会,電気学会電磁環境研究会
Jun. 2006 - State-of-the Art Seismo-Electromagnetic Research
M. Hayakawa
Invited oral presentation, English, Int'l Workshop on Seismo-Electromagnetics, Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), Quezon City, Philippines, International conference
May 2006 - Seismo-atmospheric and -ionospheric perturbations as detected by radio probing
M. Hayakawa
Invited oral presentation, English, 日本地球惑星科学連合2006年大会, 日本地球惑星科学連合
May 2006 - 2006年宮城県北部地震前の夜間気温上昇の考察
犬伏裕之; 早川正士
Oral presentation, Japanese, 日本地球惑星科学連合,日本地球惑星科学連合2006年大会
May 2006 - マルチフラクタル解析を用いたULF帯磁場データの地震前兆信号の検出
伊田裕一; 早川正士
Oral presentation, Japanese, 日本地球惑星科学連合,日本地球惑星科学連合2006年大会
May 2006 - Changes in Schumann resonance records possibly related to Taiwan earthquakes
Hayakawa, M; Ohta, K; Nickolaenko, A
Invited oral presentation, English, 6th International Confernce "Problems of Geocosmos", 6th International Confernce "Problems of Geocosmos", St. Petersburg, Russia, International conference
May 2006 - Local anomalies of parameters of ULF geomagnetic perturbations before strong earthquakes
Kopytenko, Y.A; Ismagilov, V.S; Hayakawa, M
Invited oral presentation, English, 6th International Confernce "Problems of Geocosmos", 6th International Confernce "Problems of Geocosmos", St. Petersburg, Russia, International conference
May 2006 - New ULF/ELF precursor origined in atmosphere: statistics and testing forecast hypothesis
Schekotov, A; Molchanov, O; Fedorov, E; Chebrov, V; Sinitsin, V; Gordeev, E; Belyaev, G; Hayakawa, M
Invited oral presentation, English, 6th International Confernce "Problems of Geocosmos", 6th International Confernce "Problems of Geocosmos", St. Petersburg, Russia, International conference
May 2006 - Comparison of fractal properties of ULF emissions before the Guam earthquake of August 1993 and Japanese earthquakes of June 2000
Smirnova, N.A; Hayakawa, M
Invited oral presentation, English, 6th International Confernce "Problems of Geocosmos", 6th International Confernce "Problems of Geocosmos", St. Petersburg, Russia, International conference
May 2006 - Effects of geomagnetic and seismic activity on the fractal properties of ULF emissions registered at Guam Island
Smirnova, N.A; Uritsky, V.M; Materiy I.V; Hayakawa, M
Invited oral presentation, English, 6th International Confernce "Problems of Geocosmos", 6th International Confernce "Problems of Geocosmos", St. Petersburg, Russia, International conference
May 2006 - Seismo-atmospheric and -ionospheric perturbations
M. Hayakawa
Invited oral presentation, English, IWEP(Int'l Workshop on Electromagnetic Precursors), IWEP(Int'l Workshop on Electromagnetic Precursors), Taiwan, International conference
Mar. 2006 - インドネシアスマトラ地震の前兆電磁気現象
早川正士
Invited oral presentation, Japanese, 電気学会調査専門委員会, 電気学会調査専門委員会
Mar. 2006 - レイトレース計算における反射・回析回数の検討
佐納由紀子; 河井伸一; 川村雅彦; 早川正士
Oral presentation, Japanese, 電子情報通信学会,電子情報通信学会ソサイエティ大会全国大会
Mar. 2006 - 線形予測を用いたELF帯磁界観測データからのシューマン共振の抽出法
安藤芳晃; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - ELF帯電磁波観測による中間圏発光現象に伴う雷放電の特性の解析
松戸悠; 山下幸三; 安藤芳晃; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - ELF Transiengの解析による空電源の位置と電気的特性について
山下幸三; 松戸悠; 大津山卓哉; 安藤芳晃; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - 長野松代観測点におけるULF磁場変動
九石有莉; 吉野千恵; 高橋一郎; 服部克巳; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - ULF帯磁場データのマルチフラクタル解析（ウェーブレット解析を用いた方法）
伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - WTMMを用いたULF帯地磁気データの解析
横瀬史拓; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - インドネシアスマトラ地震に電磁気現象（ULF放射と電離層擾乱）
早川正士; 太田健次; 前川慎光; 山内健; 堀江匠
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - VHF電波伝搬と気象条件の関連
米内口直之; 伊田裕一; 安田好広; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - VLF電波とfoF2の値を用いた新潟中越地震に伴う電離層擾乱の検出
堀江匠; 前川慎光; 山内健; 早川正士; 佐々木宏; 中村亨
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - スマトラ沖地震におけるULF帯磁場データ異常検出（インパルスの検出およびフラクタル解析）
白銀良輔; 伊田裕一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - Superimposed Epoch Analysisを用いた大規模地震に伴う電離層擾乱の検出
前川慎光; 山内健; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - Rescaled Range Analysisを用いた新潟中越地震に伴うVLF/LF帯伝搬異常の検出
山内健; 前川慎光; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - VHF帯干渉計システムの構築と観測結果
安田好広; 後藤剛芳; 米内口直之; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - Solar flareによる電離層擾乱の観測結果とFDTD法による伝搬シュミレーション
轟悦男; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - FDTD法による頭部九州電力の解析におけるアンテナのモデル化に関する検討
小坂直弘; 安藤芳晃; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - 北海道内陸地震発生状況と夜間気温上昇発生状況との相関について
犬伏裕之; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第74回研究発表会
Jan. 2006 - インドネシアスマトラ地震の前兆電磁気現象（日本国内観測）
早川正士; 太田健次; 堀江匠; 前川慎光
Oral presentation, Japanese, 電気学会,電気学会電磁環境研究会
Dec. 2005 - 地震に伴う電離層擾乱（VLF/LF送信局電波に基づく統計解析）
前川慎光; 山内健; 早川正士
Oral presentation, Japanese, 電気学会,電気学会電磁環境研究会
Dec. 2005 - グアム地震時のULFデータのフラクタル解析（前兆異常の検出）
伊田裕一; 早川正士
Oral presentation, Japanese, 電気学会,電気学会電磁環境研究会
Dec. 2005 - VLF/ELF空電に対する方位測定とその意義
早川正士; 太田健次
Oral presentation, Japanese, 電気学会,電気学会電磁界理論研究会
Nov. 2005 - CIP法のアンテナ解析への適用に関する検討
安藤芳晃; 早川正士
Oral presentation, Japanese, 電気学会,電気学会電磁界理論研究会
Nov. 2005 - Seismo-electromagnetics
M. Hayakawa
Invited oral presentation, English, 中国地震局地球物理研究所, 中国, International conference
Oct. 2005 - Recent studies of Schumann resonance and ELF transients
A. P. Nickolaenko; M. Hayakawa
Invited oral presentation, English, URSI GA, URSI (International Union of Radio Science) GA, India, International conference
Oct. 2005 - Anomalous effect in Shumann resonance phenomena observed in Japan, Possibly associated with the Chi-chi earthquake in Taiwan
Masashi Hayakawa; Kenji Ohta; Alexander P. Nickolaenko; Yoshiaki Ando
Invited oral presentation, English, URSI GA, URSI (International Union of Radio Science) GA, India, International conference
Oct. 2005 - Principal component analysis and singular spectrum analysis of ULF geomagnetic data associated with earthquakes
Hattori Katsumi; Aya Serita; Chie Yoshino; Masashi Hayakawa
Invited oral presentation, English, URSI GA, URSI (International Union of Radio Science) GA, India, International conference
Oct. 2005 - Seismogenic ULF emissions
M. Hayakawa
Invited oral presentation, English, Int'l Worshop on Earth, Ocean and Space, 名古屋大学STE研究所, Inuyama, Japan, International conference
Sep. 2005 - Seismo-electromagnetics: Review
M. Hayakawa
Invited oral presentation, English, Int'l Worshop on Electromagnetic Precursors, Int'l Worshop on Electromagnetic Precursors, Bandon, Indonesia, International conference
Sep. 2005 - Seismo Electromagnetic Phenomena
M. Hayakawa
Invited oral presentation, English, Mini Workshop on Electromagnetic Precursors of Earthquakes, Bandon, Indonesia, International conference
Sep. 2005 - 吸収境界条件としてのCIPと1次元BPL-FDTD法への適用
安藤芳晃; 早川正士
Oral presentation, Japanese, 電子情報通信学会,電子情報通信学会ソサイエティ大会
Sep. 2005 - 地震に伴う電磁気現象と地震予知
早川正士
Oral presentation, Japanese, 科学技術振興機構、新エネルギー・産業技術総合開発機構,Innovation Japan 2005
Sep. 2005 - 電力線高調波放射の電離層への透過の数値解析
安藤芳晃; 早川正士
Oral presentation, Japanese, 電気学会,電気学会 基礎・材料・共通部門大会
Aug. 2005 - 2003年十勝沖地震、2004年新潟県中越地震に伴うVLF/LF帯電波伝搬異常
前川慎光; 山内健; 早川正士
Oral presentation, Japanese, 電気学会,電気学会 基礎・材料・共通部門大会
Aug. 2005 - 日本国内観測における台湾地震（1999年9月23日）に伴うシューマン共振現象の異常
早川正士; 太田健次; 安藤芳晃
Oral presentation, Japanese, 電気学会,電気学会 基礎・材料・共通部門大会
Aug. 2005 - グアム地震におけるULF帯磁場データのマルチフラクタル解析
伊田裕一; 早川正士
Oral presentation, Japanese, 電気学会,電気学会 基礎・材料・共通部門大会
Aug. 2005 - シューマン共振を用いた世界雷分布同定
安藤芳晃; 早川正士
Oral presentation, Japanese, 電気学会,電気学会 基礎・材料・共通部門大会
Aug. 2005 - シューマン共振を用いた世界雷分布同定
安藤芳晃; 早川正士
Oral presentation, Japanese, 電気学会,電気学会 基礎・材料・共通部門大会
Aug. 2005 - 冬季雷のQdsの評価
松戸悠; 河守伸一郎; 関口美奈子; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - 冬季スプライトと雷放電の関係
鈴木智幸; 道本光一郎; 花田隆; 紫村孝嗣; 早川正士; 松戸悠
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - 1993年北海道南西沖地震M7.8前の夜間気温異常の統計的考察
犬伏裕之; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - 2004年紀伊半島沖地震・新潟中越地震・スマトラ沖地震の前兆現象
太田健次; 石野博一; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - 新潟県中越地震に伴うDC/ULF帯電磁放射の方位確定
早川正士; 伊田裕一; 太田健次
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - 2004年に発生した大規模地震に伴う大気及び電離層擾乱
前川慎光; 山内健; 早川正士
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - NWC VLF局の国内受信データに基づくインドネシア地震に伴う下部電離層擾乱の検出
堀江匠; 前川慎光; 早川正士; 鷹野敏明; 佐々木宏; 中村亨
Oral presentation, Japanese, 日本大気電気学会,日本大気電気学会第73回研究発表会
Jul. 2005 - De-embedding microwave fixtures with the genetic algorithm
A. S. Adalev; N. V. Korovkin; M. Hayakawa
Invited oral presentation, English, 6th international symposium on electromatnetic compatibility and electromagnetic ecology, St. Petersburg State Electrotechnical University, Saint-Petersburg, Russia, International conference
Jun. 2005 - Fractal characteristics of the natural ULF emissions in relation to geomagnetic activity
N. A. Smirnova; I. V. Yakovitskaya; M. Hayakawa; T. Itoh
Invited oral presentation, English, 6th international symposium on electromagnetic compatibility and electromagnetic ecology, St. Petersburg State Electrotechnical University, Saint-Petersburg, Russia, International conference
Jun. 2005 - Multifractal analysis for the ULF geomagnetic data during the Guam earthquake
M. Hayakawa; Yu Ida; K. Gotoh
Invited oral presentation, English, 6th international symposium on electromagnetic compatibility and electromagnetic ecology, St. Petersburg State Electrotechnical University, Saint-Petersburg, Russia, International conference
Jun. 2005 - Seismogenic ULF emissions
M. Hayakawa
Invited oral presentation, English, RAST, RAST, Istanbul, Turkey, International conference
Jun. 2005 - Seismo-ionospheric perturbations as detected by subionospheric VLF/LF propagation
M. Hayakawa
Invited oral presentation, English, RAST, RAST, Istanbul, Turkey, International conference
Jun. 2005 - 特別講演：地震に伴う電磁気現象
早川正士
Invited oral presentation, Japanese, 電波航行研究会, 電波航行研究会
May 2005 - 地震に伴う電磁現象
早川正士
Others, Japanese, 電気学会技術報告
2001