地电阻率各向异性前兆异常特征及其与地震的关系

The Research of Precursor Anomaly Characteristic of Ground Resistivity Anisotropy and Its Physical Mechanism in Earthquake

在对山东菏泽和郯城两台站提供的地震地电阻率观测资料进行必要处理的基础上,研究了地震地电阻率各向异性的前兆异常特征,得出两台站周围300 km内的5级以上地震发生前均存在明显的地电阻率各向异性前兆异常;并发现在中强地震发生时地电阻率各向异性值变化都基本处于高值附近的一个区间内,即地电阻率各向异性变化存在一个易发震区间;并从地震发生时地应力的角度讨论了易发震变化区间的物理机理。

The precursor abnormal characteristic of ground resistivity anisotropy is studied based on the data provided by Hezhe and Yancheng seismostations. The results indicate there were the distinct precursor anomalies of ground resistivity anisotropy before the above 5 magnitude earthquakes occurred within the range of 300 km of both of the seismostations. We also find that the value of anisotropy was in a stable variation range near the high value when the moderate-strong earthquakes occurred. That is, there is a variation range of ground resistivity anisotropy in which earthquake would happen likely. The physical mechanism of this range is discussed in this paper.