Electrokinetic and magnetic anomalies associated with dilatant regions in a layered Earth

Fitterman, David V.

doi:10.1029/jb083ib12p05923

Cited by 164 publications

(112 citation statements)

References 5 publications

(6 reference statements)

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“…External causes are also discarded on large robustness to environmental noises of the present observation [33]. Moreover, the order estimation of the SES strength due to several causes [34,38] suggests that the dominant causes are the piezomagnetic effect [11,13,14,39] and/or the electrokinetic effect [7,[14][15][16][17][40][41][42][43][44][45] for small stress changes such at the seismic wave frequency (see the appendix).…”

Section: Generatingmentioning

confidence: 99%

Remote Detection of the Electric Field Change Induced at the Seismic Wave Front from the Start of Fault Rupturing

Fujinawa¹,

Takahashi²,

Noda³

et al. 2011

International Journal of Geophysics

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Seismic waves are generally observed through the measurement of undulating elastic ground motion. We report the remote detection of the Earth's electric field variations almost simultaneously with the start of fault rupturing at about 100 km from the fault region using a special electric measurement. The rare but repeated detection indicates that the phenomenon is real. The characteristic time of diffusion is almost instantaneous, that is, less than 1 second to travel 100 km, more than ten times faster than ordinary seismic P wave propagation. We suggest that the measured electric field changes are produced by the electrokinetic effect through increased pore water pressure of the seismic pulse. It is also suggested that the long range propagation is due to the surface wave mode confined near the interface of the different conductivity. The length scale of the finite strength of the electric field is 16 km, 160 km for electric conductivity of 0.01, 0.001, Sm −1 , respectively. This phenomenon suggests a new seismic sensing method and a new earthquake early warning system providing more seconds of lead time.

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Section: Generatingmentioning

confidence: 99%

Remote Detection of the Electric Field Change Induced at the Seismic Wave Front from the Start of Fault Rupturing

Fujinawa¹,

Takahashi²,

Noda³

et al. 2011

International Journal of Geophysics

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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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“…Second, quantitative SP interpretation is difficult because of the complicated character of SP generation by subsurface electrokinetic sources. Theoretical studies by Nourbehecht [1963], Fitterman [1978], Ishido [1981, and Sill [1983] …”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of electrokinetic potentials associated with subsurface fluid flow

Ishido¹,

Pritchett²

1999

J. Geophys. Res.

111

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Electrokinetic and magnetic anomalies associated with dilatant regions in a layered Earth

Cited by 164 publications

References 5 publications

Remote Detection of the Electric Field Change Induced at the Seismic Wave Front from the Start of Fault Rupturing

Remote Detection of the Electric Field Change Induced at the Seismic Wave Front from the Start of Fault Rupturing

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

Numerical simulation of electrokinetic potentials associated with subsurface fluid flow

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