江苏地电阻率预测指标研究

Study on Ground Resistivity as Earthquake Prediction Index in Jiangsu Province

摘要:

结合地电阻率的前兆机理和实际观测结果，给出构造活动作用下地电阻率的两类前兆异常变化：一是与观测场地周围应力场变化相关的长趋势变化；二是与震源岩石裂隙破裂相关的大幅下降变化。针对地电阻率的两类前兆异常变化，以江苏5个地电阻率场地的历史观测数据为例，采用一年窗长的归一化速率进行分析，提出将归一化速率值的二倍方差作为地电阻率的异常指标，并对预测指标进行R值检验，得到R=0.513，对应R₀=0.277，R/R₀=1.9，预测结果较理想。

Abstract:

Based on the theoretical mechanism and the practical observation results of earth resistivity,two kinds of precursory anomalous changes of earth resistivity caused by tectonic activity are given in this paper. The first one is the long trend change related to the change of surrounding stress field,and the second one is the suddenly great change related to the fracture of rock crevice in the seismic source. In view of the two kinds of precursory anomalous variation of earth resistivity,taking the past observation data of five ground resistivity sites in Jiangsu Province as an example,using the normalized rate analysis of one-year window length,we proposed that the double variance of normalized rate value is as the anomalous index of ground resistivity. The R value test of prediction index is calculated as R=0.513,in corresponding to 97.5%confidence level R₀,R/R₀=1.9,indicating that the prediction results are sinificant.