Numerical simulation of dynamic Coulomb stress changes induced by M6.5 earthquake in Wuding, Yunnan and its relationship with aftershocks  

作　　者：虎雄林[1] 吴小平[2] 杨润海[1] 付虹[1] 胡家富[2] 黄雍[1] 

机构地区：[1]Earthquake Administration of Yunnan Province [2]Department of Geophysics, Yunnan University

出　　处：《地震学报》2008年第1期26-35,共10页Acta Seismologica Sinica

基　　金：国家自然科学基金(40364001);地震科学联合基金(605014)

摘　　要：Based on the discrete wavenumber method, we calculate the fields of dynamic Coulomb rupture stress changes and static stress changes caused by M6.5 earthquake in Wuding, and study their relationship with the subsequent after- shocks. The results show that the spatial distribution patterns of the positive region of dynamic stress peak value and static stress peak value are similarly asymmetric, which are basically identical with distribution features of aftershock. The dynamic stress peak value and the static stress in the positive region are more than 0.1 MPa and 0.01 MPa of the triggering threshold, respectively, which indicates that the dynamic and static stresses are helpful for the occurrence of aftershock. This suggests that both influences of dynamic and static stresses should be con- sidered other than only either of them when studying aftershock triggering in near field.Based on the discrete wavenumber method, this paper calculates timehistory of displacement （the theoretical seismogram of displacement） and dynamic displacement field caused by the Wuding M6. 5 earthquake. Then the time-history of strain and the dynamic strain field are obtained by elastodynamic transformation. Finally we calculate the dynamic Coulomb rupture stress chan- ges and the dynamic Coulomb rupture stress changes field caused by the Wuding M6.5 earthquake, and then discuss its relationship with the subsequent aftershocks. The results show that the spatial distribution patterns of the positive region of dynamic stress peak value and static stress are both asymmetric, which are basically identical with distribution features of the aftershocks. The dynamic stress peak value and the static stress in the positive region are more than 0.1 MPa and 0. 01 MPa of the triggering threshold, respectively, which indicates that the dynamic and static stresses are helpful for the occurrence of aftershocks.

关 键 词：武定地震 动态库仑破裂应力变化 余震 动态应力触发 

分 类 号：P315.727[天文地球—地震学]