Analysis of earth potential difference signals by using seismic wave signals

Abstract

A modified measurement method has been used to continuously observe earth potential difference (EPD) signals induced by seismic waves. This method reduces the level of extraneous signals induced by artificial and natural earth current sources. The observed signals were compared with the corresponding seismic waveforms from the Earthquake Observatory of Tohoku University, which is located 700 m from us. Comparison with each waveform component (acceleration, velocity, and displacement) showed that the proposed streaming potential model reflecting the earth acceleration adequately explains the EPD signal. The estimated ratio between the earth electrical field (potential difference) and the pressure difference in the ground, i.e., the coupling coefficient, was found to be reasonable based on the streaming potential model. © 1998 Scripta Technica, Electr Eng Jpn, 125(4): 52–59, 1998

Frequency-Dependent Streaming Potentials: A Review

“…Therefore electrokinetic phenomena are often observed in aquifers, volcanoes, and hydrocarbon or hydrothermal reservoirs. Observations show that seismoelectromagnetic signals associated to earthquakes can be induced by electromagnetic induction (Honkura et al 2009;Matsushima et al 2002) or by electrokinetic effect (Takeuchi et al 1998;Fenoglio et al 1995). The electrokinetic phenomena are due to pore pressure gradients leading to fluid flow in the porous media or fractures, and inducing electrical fields.…”