【摘要】 对汶川MS8.0地震震中周围17个台站的地电阻率观测资料进行了处理.以2007年的地电阻率观测数据为背景值,计算出每一个台站NS和EW两个测向2008年的地电阻率月均值相对变化的绝对值,然后选择较大的值作为当月的相对变化值.最终获得了汶川地震前5个月的地电阻率异常变化图像.结果表明,随着发震时间的临近,地电阻率异常分布的范围逐渐缩小,并最终集中分布在汶川地震震中附近;在临近发震时间(2008年3,4月),地电阻率异常分布的长轴方向与汶川MS8.0地震的破裂方向、龙门山断裂带走向或地震烈度分布的长轴方向几乎垂直,而与其震源机制解的主压应力轴方向基本一致.更多还原

【Abstract】 Geo-resistivity data recorded at 17 stations around the epicenter of the Wenchuan MS8.0 earthquake were processed. Taken the geo-resistivity data in 2007 as background values, the absolute values of relative variations of monthly average value in NS and EW directions in 2008 were calculated, and then the larger one was chosen as the relative variation of each month. At last the variation images of geo-resistivity anomaly for the 5 months before the Wenchuan earthquake were obtaind. The results show that, as the occurrence time of the earthquake drew near, the spatial variation of geo-resistivity anomaly shrinked gradually and finally concentrated in the area near the epicenter. In the period just before the earthquake (March and April, 2008), the major axis of geo-resistivity anomaly was almost perpendicular to the rupture direction of the Wenchuan MS8.0 earthquake and the strike of Longmenshan fault or the major axis of the distribution of seismic intensity, but nearly parallel to the principal compressive stress axis from focal mechanism solution.更多还原