2006年珊溪水库M_(L)4.6震群静态库仑应力变化及其对后续地震的影响  

Study on static Coulomb stress variation of Shanxi reservoir M_(L)4.6 earthquake and its influence on subsequent earthquakes

作　　者：袁文秀 汪贞杰 张丽芬[2] 于俊谊 龚俊 袁俊 YUAN Wenxiu;WANG Zhenjie;ZHANG Lifen;YU Junyi;GONG Jun;YUAN Jun(Zhejiang Earthquake Agency,Hangzhou 310013,China;Key Laboratory of Earthquake Geodesy,Institute of Seismology,China Earthquake Administration,Wuhan 430071,China;Jiangxi Earthquake Agency,Nanchang 330039,China)

机构地区：[1]浙江省地震局,中国杭州310013 [2]中国地震局地震研究所(地震与大地测量重点实验室),中国武汉430071 [3]江西省地震局,中国南昌330039

出　　处：《地震地磁观测与研究》2023年第5期18-28,共11页Seismological and Geomagnetic Observation and Research

基　　金：浙江省地震局科技项目(项目编号:2020zjj03)。

摘　　要：浙江省珊溪水库2006年2月4日至11日发生8个M_(L)4以上地震,最大地震为M_(L)4.6地震,截至2009年12月10日,共发生1063次小地震。为探讨8个M_(L)4以上地震主发震断层的库仑应力变化特征以及库仑应力变化对后续地震发生的促进作用,基于库仑破裂准则,计算珊溪水库该M_(L)4.6震群的静态库仑应力变化,讨论不同有效摩擦系数对库仑应力变化的影响,并依据Dieterich速率—状态摩擦定律计算并讨论其静态库伦应力变化对后续地震活动性的影响。结果表明,珊溪水库8次M_(L)4.0以上地震的静态库仑应力变化及库水下渗导致的静摩擦力变化,对后续地震的发生起到一定促进作用,约76.3%的地震发生在库仑应力变化为正的区域;有效摩擦系数的取值对库仑应力场与余震分布之间的关系影响不大;计算F_(11-1)、F_(11-2)及F_(11-3)分支断层中部的库仑应力变化,发现库仑应力在F_(11-1)、F_(11-2)断裂上降低,在F_(11-3)断裂上增加,表明未来地震在F_(11-3)断裂附近多发的可能性更大。From February 4th to 11th,2006,there were 8 earthquakes of M_(L)4 or above at Shanxi reservoir in Zhejiang Province,with the largest earthquake being the M_(L)4.6 earthquake.As of December 10th,2009,a total of 1063 small earthquakes had occurred.In order to explore the Coulomb stress variation characteristics of the main fault of 8 M_(L)4 and above earthquakes,as well as the promoting effect of Coulomb stress variation on subsequent earthquakes,based on the Coulomb failure criterion,the static Coulomb stress variation of the M_(L)4.6 earthquake swarm in Shanxi reservoir was calculated,and the influence of different effective friction coefficients on Coulomb stress variation was discussed.And calculate and discuss the impact of static Coulomb stress changes on subsequent seismic activity based on Dietrich’s rate state friction law.The results show that the static Coulomb stress changes and the static friction force changes caused by the infiltration of reservoir water in 8 M_(L)4.0 and above earthquakes in the Shanxi reservoir have played a certain promoting role in the occurrence of subsequent earthquakes.About 76.3%of earthquakes occur in areas with positive Coulomb stress changes;the effective friction coefficient has little effect on the relationship between the Coulomb stress field and aftershock distribution;calculation of the Coulomb stress changes in the middle of F_(11-1),F_(11-2),and F_(11-3)branch faults showed that Coulomb stress decreased on F_(11-1)and F_(11-2)faults,and increased on F11-3 faults,indicating a greater likelihood of future earthquakes occurring near F_(11-3)faults.

关 键 词：静态库仑应力变化 有效摩擦系数 水库地震 

分 类 号：P315.727[天文地球—地震学] TV697.24[天文地球—固体地球物理学]