Dependence of seismoelectric amplitudes on water content
Dependence of seismoelectric amplitudes on water content
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DOI：
10.1111/j.1365-246x.2011.05232.x
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发表时间：
2011-12
影响因子：
2.8
通讯作者：
M. Strahser;L. Jouniaux;P. Sailhac;P. Matthey;M. Zillmer
中科院分区：
文献类型：
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作者：
M. Strahser;L. Jouniaux;P. Sailhac;P. Matthey;M. Zillmer
地震电场测量的目的是实现电特性对含水量和渗透率的敏感性与地震勘探的高空间分辨率的结合。更好地了解物理过程和地震能量与电能之间转换的可靠量化是必要的，并且需要考虑含水量的影响，特别是对于浅层地下调查。我们进行了实地调查，以量化的地震电信号的水含量的变化。我们测量了地震波传播引起的震电信号，通过在几个月内重复观察相同的两个剖面。监测电阻率以考虑含水量变化。结果表明，相对于地震加速度水平分量归一化的地震动电场水平分量与电阻率ρ 0.42±0.25成反比。假设所观察到的电阻率变化仅取决于含水量，该结果意味着动电系数应随含水饱和度的增加而增加。考虑含水饱和度的影响，结合阿尔奇非饱和电阻率定律，归一化地震电场为有效饱和度的幂律，指数为（0.42 ± 0.25）n，n为阿尔奇饱和指数。
SUMMARY The expectation behind seismoelectric field measurements is to achieve a combination of the sensitivity of electrical properties to water content and permeability and the high spatial resolution of seismic surveys. A better understanding of the physical processes and a reliable quantification of the conversion between seismic energy and electric energy are necessary, and need to take into account the effect of water content, especially for shallow subsurface investigations. We performed a field survey to quantify the seismoelectric signals as the water content changed. We measured seismoelectric signals induced by seismic wave propagation, by repeating the observations on the same two profiles during several months. The electrical resistivity was monitored to take into account the water content variations. Weshowthatthehorizontalcomponentoftheseismoelectricfield,normalizedwithrespectto the horizontal component of the seismic acceleration is inversely proportional to the electrical resistivity ρ 0.42±0.25 . Assuming that the observed resistivity changes depend only on the water content, this result implies that the electrokinetic coefficient should increase with increasing water saturation. Taking into account the water saturation and combining our results with the Archie law for the resistivity in non-saturated conditions, the normalized seismoelectric field is a power-law of the effective saturation with the exponent (0.42 ± 0.25)n where n is Archie’s saturation exponent.