长江三峡工程库首区诱发地震危险性研究

STUDY ON RISK OF INDUCED EARTHQUAKE IN RESERVOIR HEAD REGION OF THREE GORGES PROJECTION ON YANGTZE RIVER

对国内外及三峡工程邻区的水库震例研究表明 ,诱发地震的形成及其诱震地点、强度是受水库区地质环境影响和制约的 ,因而水库地震危险性预测主要是依据库区的诱发地震环境条件。在研究长江三峡水库诱发地震地质环境条件的基础上 ,采用地质环境和概率分析两种方法对库首区蓄水后的诱发地震危险性进行了评估 ,认为本区发生中、强地震的可能地点是九湾溪断裂和仙女山断裂北端 ,诱发地震的震级上限为 5 .

The case study on reservoir earthquakes home and abroad and in the Three Gorges projection and its vicinity shows that the generation, place and intensity of the induced earthquake are affected and controlled by geological environment. Consequently, the prediction of reservoir earthquake risk is based basically on the environmental conditions of induced earthquake in the reservoir area. On the basis of investigation of the geological environmental conditions of reservoir earthquake in the Three Gorges on Yangtze River we have estimatied the seismic risk of induced earthquake in the reservoir head region by two methods:analysis of geological environment and probability analysis.We consider that the places where the earthquakes of \%M\%s 5.5 or less will occur probably are the north ends of the Jiuwanxi and Xiannushan faults.