研究瀑布沟水库蓄水前库区地震的活动性以及震源机制、应力场等震源参数的性质，为水库蓄水之后可能诱发地震活动的监测、成因及类型鉴别给出可供依据的参考。研究结果显示，水库库尾边缘西部地震活动水平相对较高；库中段的中小地震活动水平相对较弱；大坝附近的库首段地震活动水平相对较低，震源深度主要集中在5—15km。研究区内小震震源机制解结果显示，瀑布沟水库蓄水前小震主要为走滑型地震，蓄水区与研究区平均应力场总体呈NW方向。

 For providing reference of causes and types judging, monitoring for possible triggering earthquakes after impoundment, in this paper, the seismicity, focal mechanism and stress field before impoundment were analyzed. The result shows that compared with middle segment of reservoir the seismicity in the west of reservoir was relatively in high level, and in the region adjacent to dam it was in relatively low. The depth of earthquakes distribute in 5 to 15 km. the statistic result of focal mechanisms indicate that strike-slip earthquakes stand for high proportion. The mean stress field in water area and whole research region has some difference, but were in NW direction.