昆仑山口西8.1级地震前新疆定点形变异常初析

PRELIMINARY ANALYSIS ON XINJIANG FIXED-POINT DEFORMATION ANOMALY BEFORE THE M=8.1 EARTHQUAKE IN THE WEST OF THE KUNLUN MOUNTAIN PASS

昆仑山口西 8.1级地震发生在新疆形变监测台网的东南 ,距震中 70 0— 1 2 0 0 km范围内有 6台项资料显示出地壳形变前兆异常。分析认为地壳形变异常具有一定的阶段性特征 ,中短期异常多出现在 NS向 ,8.1级地震前 2 0天 EW向出现加速或反向突变 ,临震前 4天重力仪记录到强烈的地脉动异常。这些异常的出现与 2 0 0 0— 2 0 0 1年中国西部地区 3次明显的地壳水平运动在时间上有一定的相关性。

The M8.1 earthquake in the west of the Kunlun Mountain Pass is located at the southeast of the Xinjiang Deformation Monitoring Network, which is 700-1200 km from the epicenter. Six kinds of records in the network showed anomalies before the shock; and the anomalies in different stages had different features. The medium- or short-term anomalies much appeared in NS direction; speeding up or sudden reverse changes appeared in EW direction 20 days before the event; and the strong pulsating movement could be recorded by the gravimeter 4 days before the event. It is thought that the appearance of the anomalies is related with three times of obvious crustal horizontal movements in West China in 2000-2001.