三峡水库诱发地震的监测与预报（英文）

Induced Earthquake Monitoringand Forecast of Three Gorges Reservoir

三峡水利枢纽规模宏大,举世瞩目,具有巨大的防洪、供水、发电、航运等综合效益,是开发治理长江的骨干工程.三峡工程建在坚实的花岗岩基础上,三峡水库已初步形成.根据最大历史地震震级并适当加权,确定库区最大可信地震为6级左右.在仙女山和九湾溪断裂一带,(距坝址为18km)存在诱发地震的可能,震级ML在5.0~5.8级.对坝址的影响烈度为VI度,不会对按烈度VII度设防的枢纽主要建筑物构成直接威胁.三峡水库蓄水运行后,地震频次与强度虽有所增加,但地震活动仍保持在三峡地区原有弱地震活动本底状态[1,2].三峡工程在1993年开工,2009年全部建成.三峡水库在2003年6月开始蓄水,并从2010年10月26日起,连续6年试验性蓄水到175m.三峡水库总长660km,平均宽度1.0~1.5km,总水域面积1 084km2.随着库水位升高,库容及水域面积加大,发生水库诱发地震的可能性也将加大.必须加强对三峡水库诱发地震的监测与预报,预防地震及地质灾害,确保工程建设及运行安全,构建和谐社会,促进库区长治久安.

The Three Gorges Project （TGP） on the Yangtze River （YR） is the largest hydropower station in the world; possessing comprehensive benefits mainly for flood control, drought relief, power generation and navigation improvement. TGP will be an important and backbone project in harnessing and developing of the YR. TGP is built on a strong granite foundation. According to the magnitude records of historical maximum earthquake and properly weighted, the maximum reliable earthquake of TG（Three Gorges） reservoir would be ML6 magnitude. There is the proba- bility of ML 5.0--5.8 induced earthquake around the Xianntishan and Jiuwanxi fault zone （18 km upstream of the dam）. However, the highest intensity of earthquake around the dam site would not exceed Degree VI; whereas the main structures of TGP were designed with seismic intensity of Degree VII; hence the reservoir induced earthquake would not form direct threat to the main structures of TGP. After the impoundment and operation of TG reservoir, the frequency and in- tensity of earthquake have been increased in some extent; yet the earthquake activities at TG res- ervoir region still keep in an original weak earthquake activities status. TGP was commenced in 1993 and the whole project completed in 2009. Three Gorges reservoir has been formed since June 2003 and impounded to normal pool level （NPL） 175 m 6 times year by year since Oct. 26, 2010. The reservoir has a total length of 660 km and an average width of 1.0--1.5 km, with a total waters area of 1084 kmz. In pace with the pool level raised, the storage enlarged, the probability of reservoir earthquake would be enlarged. We should strengthen the TGP induced earthquake mo- nitoring and forecast, prevent the earthquake and geological calamity, ensure the safety of the dam construction and operation, form the harmonious society as well as guarantee the long term security.