A new interpretation of magnetic field variation associated with the Matsushiro earthquakes.

Mizutani, Hitoshi; Ishido, Tsuneo

doi:10.5636/jgg.28.179

Cited by 77 publications

(30 citation statements)

References 12 publications

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“…Although presented models seem to explain some specific aspects of the ULF observations, no complete theory is so far available. There are at least three mechanisms which have been proposed for the generation of earth currents as sources of ULF emissions: (1) Electrokinetic effects (e.g., Mizutani and Ishido, 1976;Fitterman 1978Fitterman , 1979Fitterman , 1981Ishido and Mizutani 1981;Dobrovolsky et al 1989;Fenoglio et al 1995), (2) Induction effects (Draganov et al 1991;Surkov 1999), and (3) Microfracturing effects Hayakawa 1995, 1998). Fenoglio et al (1995) tried to explain the ULF geomagnetic properties associated with the 1989 Loma Prieta earthquake by electrokinetic effects.…”

Section: Possible Physical Mechanismmentioning

confidence: 99%

ULF Geomagnetic Changes Associated with Large Earthquakes

Hattori¹

2004

Terr. Atmos. Ocean. Sci.

209

130

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3291 Marine Biosystems Research Center, Chiba University, Inage, Chiba, Japan *Corresponding author address: Prof. Katsumi Hattori, Marine Biosystems Research Center, Chiba University, Inage, Chiba, Japan; E-mail: hattori@earth.s.chiba-u.ac.jp Despite its extreme importance and years of effort, practical short-term earthquake prediction still remains to be seen. However, research in earthquake-related electromagnetic phenomena have recently shown that such phenomena make for a promising candidate for short-term earthquake prediction. There is a good deal of accumulated evidence of precursory signatures in a wide frequency range (DC-VHF). ULF geomagnetic change is one of the most promising phenomena and it suggests that short-term prediction is realizable. This report first reviews earlier observational facts and presents the latest results in detection of ULF emissions by means of sophisticated signal processing. Finally, we discuss the possible generation and propagation mechanism of earthquake-related ULF signals.

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Section: Possible Physical Mechanismmentioning

confidence: 99%

ULF Geomagnetic Changes Associated with Large Earthquakes

Hattori¹

2004

Terr. Atmos. Ocean. Sci.

209

130

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“…Electrokinetic phenomena are applicable in many geophysical research areas, including monitoring subsurface flows in oil reservoirs and in geothermal areas, and monitoring the activity of volcanoes. Mizutani et al (1976) first proposed a model in which during the dilatancy stage, which is assumed to precede earthquakes, pore pressure in the dilatant region decreases and water flows into this region from the surrounding area, generating electric and magnetic precursors to earthquakes due to electrokinetic effects. Since then, many models have been proposed (e.g., Corwin and Morrison 1977;Fitterman 1981;Revil et al 1999;Ishido and Pritchett 1999).…”

Section: Electrokinetic Effectmentioning

confidence: 99%

A Report from the RIKEN International Frontier Research Project on Earthquakes (IFREQ)

Uyeda¹,

Nagao²,

Tanaka³

2004

Terr. Atmos. Ocean. Sci.

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ABSTRACT1 Earthquake Prediction Research Center, Tokai University, Shizuoka, Japan * Corresponding author address: Prof. S. Uyeda, Earthquake Prediction Research Center, Tokai University, Shimizu Orido, Shizuoka, Japan; Mitigation of seismic hazards requires integration of science and human action, namely the science of earthquakes, anti-seismic engineering and socio-political measures. In this paper, we will be primarily examining the problem of saving human life from earthquakes. Loss of human life from earthquakes is caused overwhelmingly by the collapse of houses and buildings within less than a few minutes of the main shocks. When structural damage is reduced, most other seismic hazards will also be reduced. On top of that, if short-term prediction could be made, casualties would be further reduced dramatically. We review the state of the art in short-term prediction, in particular recent progress in approaches using electromagnetic phenomena.The RIKEN International Frontier Research Project on Earthquakes (IFREQ) has demonstrated the existence of pre-seismic ultra-low frequency (ULF) geo-electric potential changes, a claim that has long been made by the Greek VAN group. In addition, IFREQ has been able to verify the precursory signatures of ULF geomagnetic variations. A review is also made for another promising method using pre-seismic over-the-horizon transmission of VHF (~100MHz) FM radio waves. Thus, the reinforcement of existing structures and enhancement of short-term prediction research are the two keys for seismic hazard mitigation.

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“…Electrokinetically generated electric and magnetic fields [Mizutani and Ishido, 1976;Fitterman, 1978Fitterman, , 1979 [Loeb, 1958]. Charge generation by rapid fluid disruption is thus a well-known phenomenon and is not, of much concern if this charge is generated in a conducting environment, since it will quickly decay [Locknet et al, 1983].…”

Section: Physical Backgroundmentioning

confidence: 99%

Rapid fluid disruption: A source for self‐potential anomalies on volcanoes

Johnston¹,

Byerlee²,

Lockner³

2001

J. Geophys. Res.

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Abstract. Self-potential (SP) anomalies observed above suspected magma reservoirs, dikes, etc., on various volcanoes (Kilauea, Hawaii; Mount Unzen, Japan; Piton de la Fournaise, Reunion Island, Miyake Jima, Japan) result from transient surface electric fields of tens of millivolts per kilometer and generally have a positive polarity. These SP anomalies are usually attributed to electrokinetic effects where properties controlling this process are poorly constrained. We propose an alternate explanation that contributions to electric fields of correct polarity should be expected from charge generation by fluid vaporization/disruption. As liquids are vaporized or removed as droplets by gas transport away from hot dike intrusions, both charge generation and local increase in electrical resistivity by removal of fluids should occur. We report laboratory observations of electric fields in hot rock samples generated by pulses of fluid (water) through the rock at atmospheric pressure. These indicate the relative amplitudes of rapid fluid disruption (RFD) potentials and electrokinetic potentials to be dramatically different and the signals are opposite in sign. Above vaporization temperatures, RFD effects of positive sign in the direction of gas flow dominate, whereas below these temperatures, effects of negative sign dominate. This suggests that the primary contribution to observed self-potential anomalies arises from gas-related charge transport processes at temperatures high enough to produce vigorous boiling and vapor transport. At lower temperatures, the primary contribution is from electrokinetic effects modulated perhaps by changing electrical resistivity and RFD effects from high-pressure but low-temperature COe and SOe gas flow ripping water molecules from saturated crustal rocks. If charge generation is continuous, as could well occur above a newly eraplaced dike, positive static potentials will be set up that could be sustained for many years, and the simplest method for identii•ying these hot, active regions would be to identi•y the SP anomalies they generate.

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A new interpretation of magnetic field variation associated with the Matsushiro earthquakes.

Cited by 77 publications

References 12 publications

ULF Geomagnetic Changes Associated with Large Earthquakes

ULF Geomagnetic Changes Associated with Large Earthquakes

A Report from the RIKEN International Frontier Research Project on Earthquakes (IFREQ)

Rapid fluid disruption: A source for self‐potential anomalies on volcanoes

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