Evolution of cumulative Coulomb failure stress in northeastern Qinghai-Xizang (Tibetan) Plateau and its effect on large earthquake occurrence  

作　　者：万永革 沈正康 曾跃华 盛书中 

机构地区：[1]State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration [2]U.S.Geology Survey,Golden CO 80401,USA [3]Institute of Geophysics,China Earthquake Administration

出　　处：《Acta Seismologica Sinica(English Edition)》2007年第2期117-132,共16页

基　　金：National Natural Science Foundation of China(40374012 and 40334042);State Key Fundamental Research De-velopment Plan Project(2001CB711005)

摘　　要：We simulate accumulative Coulomb failure stress change in a layered Maxwell viscoelastic media in the northeastern Qinghai-Xizang （Tibetan） Plateau since 1920. Lithospheric stress/strain evolution is assumed to be driven by dislocations of large earthquakes （M≥7.0） and secular tectonic loading. The earthquake rupture parameters such as the fault rupture length, width, and slip are either adopted from field investigations or estimated from their statistic relationships with the earthquake magnitudes and seismic moments. Our study shows that among 20 large earthquakes （M≥7.0） investigated, 17 occurred in areas where the Coulomb failure stress change is positive, with a triggering rate of 85%. This study provides essential data for the intermediate to long-term likelihood estimation of large earthquakes in the northeastern Tibetan Plateau.We simulate accumulative Coulomb failure stress change in a layered Maxwell viscoelastic media in the northeastern Qinghai-Xizang （Tibetan） Plateau since 1920. Lithospheric stress/strain evolution is assumed to be driven by dislocations of large earthquakes （M≥7.0） and secular tectonic loading. The earthquake rupture parameters such as the fault rupture length, width, and slip are either adopted from field investigations or estimated from their statistic relationships with the earthquake magnitudes and seismic moments. Our study shows that among 20 large earthquakes （M≥7.0） investigated, 17 occurred in areas where the Coulomb failure stress change is positive, with a triggering rate of 85%. This study provides essential data for the intermediate to long-term likelihood estimation of large earthquakes in the northeastern Tibetan Plateau.

关 键 词：earthquake triggering northeastern Tibetan Plateau cumulative Coulomb stress change 

分 类 号：P315.7[天文地球—地震学]