Electric Signals on and under the Ground Surface Induced by Seismic Waves
Electric Signals on and under the Ground Surface Induced by Seismic Waves
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DOI：
10.1155/2012/270809
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发表时间：
2012-02
影响因子：
1.1
通讯作者：
A. Takeuchi;K. Okubo;N. Takeuchi
中科院分区：
文献类型：
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作者：
A. Takeuchi;K. Okubo;N. Takeuchi
我们在日本东北部建立了三个观测点(Honjo、Kyowa和Sennan)，以电容式大平板电极(4×4m2)作为传感器支撑在离地面4m处，并在0.5m和2.5m深度垂直埋设一对参比电极(仅在Sennan使用地速传感器)。对日本东北部6.3级地震的电信号与地震波进行了同步检测。它们的波形是衰减的振荡，不同地点的信号幅度差别很大。所有电极检测到的信号幅度之间有很好的正相关关系。我们提出了一种信号产生模型：地震加速度垂直震动表土中的孔隙水，产生上非饱和水带和下饱和水带之间的垂直流动势。当一个电极在饱和水区，另一个电极在非饱和水区时，观察到最大的地电位差，而当电极在饱和水区时，则没有观察到最大电势差。流动电势在地面形成电荷，产生垂直大气电场。大平板电极检测到与电极和地面之间的电势差有关的电信号。
We constructed three observation sites in northeastern Japan (Honjo, Kyowa, and Sennan) with condenser-type large plate electrodes (4 × 4 m2) as sensors supported 4 m above the ground and with pairs of reference electrodes buried vertically at 0.5 m and 2.5 m depth (with a ground velocity sensor at Sennan only). Electrical signals of an earthquake (M6.3) in northeastern Japan were detected simultaneously with seismic waves. Their waveforms were damped oscillations, with greatly differing signal amplitudes among sites. Good positive correlation was found between the amplitudes of signals detected by all electrodes. We propose a signal generation model: seismic acceleration vertically shook pore water in the topsoil, generating the vertical streaming potential between the upper unsaturated water zone and the lower saturated water zone. Maximum electric earth potential difference was observed when one electrode was in the saturated water zone, and the other was within the unsaturated water zone, but not when the electrodes were in the saturated water zone. The streaming potential formed a charge on the ground surface, generating a vertical atmospheric electric field. The large plate electrode detected electric signals related to electric potential differences between the electrode and the ground surface.