地下电性非均匀结构对地电场信号的影响

在数值模拟的基础上探讨了地下电性非均匀性问题对地电场信号的影响程度。这些影响主要包括地下电性非均匀体对天然电磁感应电场的影响和对产生于震源区附近的异常地电场的影响。结果表明, 地下电性不均匀体的电性特征与周围介质的电性特征差别越大, 则其对地电场的影响也会越大; 地下电性不均匀体的空间范围越大, 则其对地电场的影响也越大。在孕震区作为可能的电荷源模型中, 地下电性不均匀体的存在对电荷源所形成的异常地电场信号在地表的表现形式也有很大的影响。在地表所观测到的地电场异常空间分布不均匀性与地下电性不均匀体的空间位置有着密切关系。

The influence of inhomogeneous geoelectric structure on the signals of geoelectric field

Based on the results of numerical simulation, this paper studied the influence of in homogeneous geoelectrical structure on the signals of geoelectric filed. It mainly in-cludes influence of inhomogeneous geoelectrical structure on the geoelectrical field pro-duced by natural electro magnetic induction and the abnormal geoelectric field produced. near the hypocenter area. The results show that the bigger the difference of the electricalfeature between the inhomo geneous body and its country rock is,the more influence the inho mogeneous body exerts on the geoelectric field; the larger the special dimension of the in homogeneous body is the more influence exerts on the geoelectric field. The existence of the inhomog eneous geoelectric structure also produces an important influence on the form of the ground distribution of the abnormal geoelectric field coming from hypocenter areas in the model, in which the seismogenic areas are regarded as a kind of charge source. The special distribution of abnormal geoelectrical fieldis closely related to the existence of in-homo geneous medium beneath the surface.