We have studied seismoelectric (SE) surface-wave signals and found that they can be used to infer changes in the SE coupling properties at depth. SE surface-wave signals have much higher amplitudes than SE body-wave signals. We measured the seismic and the electrical potential or electromagnetic (EM) field along the surface of the earth. We used dispersive relative spectral amplitudes (DRSAs) that measure the frequency-dependent relative strength of electrical signals versus seismic signals associated with SE surface-wave signals. We find that DRSAs have sensitivity to contrasts in the electrokinetic coupling coefficient and other relevant petrophysical properties at depth. Our discovery can mitigate the major limitation that plagues body-wave-based SE methods: the relative weakness of the converted EM signals from seismic body waves. We envision applications to characterize subsurface rock, fluid, and fluid-flow properties (e.g., porosity, permeability, and dynamic fluid viscosity, salinity) in the near surface, for aquifers, and shallow geothermal reservoirs.

中文翻译：

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地震电波分析，利用色散相对频谱幅度表征地层性质

我们研究了地震电（SE）面波信号，发现它们可用于推断深处SE耦合特性的变化。SE面波信号的幅度比SE体波信号高得多。我们测量了地球表面的地震场，电位场或电磁场（EM）。我们使用了色散相对频谱幅度（DRSA），用于测量电信号相对于与SE表面波信号相关的地震信号的频率相关相对强度。我们发现，DRSA在深度上对电动耦合系数和其他相关岩石物理特性的对比具有敏感性。我们的发现可以缓解困扰基于体波的SE方法的主要局限性：地震体波转换后的EM信号的相对弱点。