Abstract: The Hunanzhen reservoir with a dam 129m high and a volume of 2.06 billion m³ is located in Quxian County, Zhejiang province. The seismic activity started along the bank 15km up stream from the dam, 5 months after impounding of this reservoir. The earthquake of magnitude 2.8(Ms)occurred on October 7, 1979 and caused a light damage in the central area. A mobile seismograph was installed in the epicentral area and from March 14 to May 26, 1980 1483 tremors were recorded. Most of them are ultramicroear-thquakes and have a regular distribution in space with extremely shallow depth. The seismic activities vary with the water level sensitively and lag in a short time. Based on the geological environment and macroscopic characteristics of seismic records it can be suggested that the seismicity is likely to be caused by the gravitational slip of the unstable rock masses on the banks beneath the reservoir studied.

摘要： 湖南镇水库蓄水后五个月,在大坝上游15公里库岸边开始出现地震。这些地震大部分是极微震。震源位置变化不大,深度极浅。地震活动对库水位变化的反映十分明显,滞后时间很短。根据库区地质、地震记录和宏观的一些特点,推测地震可能是库岸不稳定岩体的水下重力滑移引起的。