地震工程学报Issue(2)：512-517,6.DOI:10.3969/j.issn.1000-0844.2015.02.0512
重庆三江口水库诱发地震分析研究
Reservoir-induced Earthquakes for the Sanjiangkou Reservoir in Chongqing
摘要
Abstract
Based on field investigations and previous research results,this study analyzes the tec-tonic background,seismic activity,and hydrogeology condition of the Sanjiangkou reservoir area. The Yushan fault is the main fault located in the southeast margin of the Sanjiangkou reservoir area.The other major fault is termed the Mawu fault,which is exposed in the west margin of the Sanjiangkou reservoir area.The active age of the Yushan fault is mid-Pleistocene and the Mawu fault is pre-Quaternary.The level of historic and current seismicity is low in the reservoir area. Employing structural analogy and probabilistic statistic methods,the probability of the induced earthquake in the Sanjiangkou reservoir area is discussed.These results are used to compare the Sanjiangkou reservoir with other reservoirs that have experienced earthquakes.The structural analogy method analysis showed that the possibility of tectonic-type reservoir-induced earth-quakes is small following impoundment.However,there is the possibility of a karst subsidence-type reservoir-induced earthquake.This event could occur because of the existence of a large amount of thick layers of limestone in the reservoir area that could foster karst development.The loading and infiltration effects of water may easily cause rock collapse and crack propagation in the karst cave.This would induce a karst subsidence-type reservoir-induced earthquake.Consider-ing the conditions of the Sanjiangkou reservoir area eight induced earthquake factors were selected to conduct the probabilistic prediction of the earthquake magnitude.These factors were reservoir water depth,lithology,regional state of stress,fault activity,degree of karst development,fault permeable depth,communication with the reservoir water,and seismic activity background.Based on the geological conditions and induced earthquake environment of the Sanjiangkou reservoir area,the reservoir area was divided into three segments:the head (Xintanzi-Shiliwan),middle (Shiliwan-Niubizi),and end (Niubizi-Xiamakou)regions.Using the MATLAB software pro-gramming,the probability of five earthquake magnitude was calculated for the three segments. The larger earthquake magnitude grading range was selected that corresponded to the relative probability value.The grading range was considered as the possible earthquake magnitude.The probabilistic statistic method analysis showed that the reservoir’s head region (Xintanzi-Shili-wan)had a small possibility of an induced earthquake with a possibility of earthquake occurrence of 0.02.The reservoir’s middle region (Shiliwan-Niubizi),where the karst development is un-likely,had a possibility of induced earthquake of 0.96.The end region (Niubizi-Xiamakou)may induce microseismic activity with the possibility of induced M L (M < 3.0)of 0.10.关键词
三江口水库/构造类比法/概率预测法/水库诱发地震/发震概率Key words
the Sanjiangkou reservoir/structural analogy method/probabilistic statistic method/reservoir-induced earthquake/possibility of earthquake occurrence分类
天文与地球科学引用本文复制引用
吴建超,张丽芬,汪旭涛,蔡永建..重庆三江口水库诱发地震分析研究[J].地震工程学报,2015,(2):512-517,6.基金项目
中国长江三峡集团公司科研专项基金(SXSN/3354) （SXSN/3354）
