Abstract: 136 earthquakes,taking place in the west of Xietan area,recorded by portable stations deployed in the Three Georges reservoir area were relocated using the double difference algorithm.The relocations show that the root-mean-square shifts of the relocations in the directions of E-W,N-S and U-D are 0.38km,0.33km and 0.98km,respectively.The earthquakes in clasolite area with the focal depths about 4～5km take on linear distributions from shallow to deep part.These earthquakes were deduced as reservoir induced earthquake of fault fracture type.In the contrast,the earthquakes in limestone pavement with the focal depths about 2～3km take on slightly divergent distribution and have the characters of reservoir induced earthquake of the karts collapse type.

Key words: Three Gorges reservoir, double-difference algorithm, reservoir induced earthquake, karts collapse

摘要： 利用三峡流动观测台网的地震记录,采用双差定位法对三峡水库泄滩西的136个地震进行了重新定位。重新定位后,地震在E-W、N-S和U-D 3个方向的均方根偏移分别为0.38、0.33和0.98km。定位结果表明:水库北岸碎屑岩区地震震源深度4～5km,地震从浅到深呈线性分布,为断层破裂型水库诱发地震;水库南岸灰岩区地震震源深度2～3km,地震略呈发散分布,具有岩溶塌陷型水库诱发地震的特点。

关键词: 三峡水库, 水库诱发地震, 双差定位, 断层破裂型