漫湾水库蓄水前后库区地震活动性与构造应力场分析

Analysis of Seismicity and Tectonic Stress Field at the Manwan Reservoir Area before and after the Water Storage in the Reservoir

对漫湾水库蓄水诱发地震作了分析,结果表明,蓄水后库区小震频次明显增加,近距离地震明显增多,在蓄水首次达到高水位和由高水位突降至低水位时,诱发了最强地震。表明蓄水对库区构造应力场产生了影响,使得局部应力场较区域构造应力场作用方向出现明显偏转,作用方式发生改变,呈现较大的垂直作用效应,节面错动出现较大正倾滑动分量。

The earthquakes induced by the Manwan reservoir are analyzed in this paper. It is discovered that the frequence of small earthquakes obviously increased in the reservoir area and more near-distance earthquakes occurred after the water storage. The strongest earthquake was induced while the water level reached the highest and dropped suddenly from the highest to the lowest. The water storage makes the direction of the stress field in the reservoir area obviously deviate comparing with that of the regional stress field, and the function pattern was also changed, showing larger vertical function and normal tilt-slipping component in the dislocation of node plane.