地电阻率各向异性度的动态演化与汶川地震孕育过程

汶川地震后，利用中国地震前兆观测台网的资料，对地震前后地电阻率各向异性度进行了分析。结果表明，汶川地震前，我国西部地区，特别是临近四川地区台站地电阻率各向异性度的变化较为明显。在震前5～6年内，西部地区部分台站地电阻率各向异性度开始出现准同步下降变化，震前2年内，这种下降变化有加速的迹象，并且下降幅度随着震中距离的减小而增大，汶川地震后，部分台站的异常形态开始恢复。经分析，我们认为这种变化可能与孕震区地下应力场调整有关。

Study on the ground resistivity anisotropic variation and the process of Wenchuan earthquake preparation

Based on the geoelectric observation data from National Center of Seismic Precursory Sta- tion Network,we systematically analyzed the dimensionless factor S defined from the ground resistivity anisotropy pre- and post-Wenchuan earthquake. The result shows that most S began to decrease synchronously since 5-6 years before quake and the decreasing rate began more and more rapidly with the passage of time. After Wenchuan earthquake, most of the S anomalies began to recovery. This variation of the degree of ground resistivity anisotropy may relate to the process seismic stress accumulation and release.