汶川地震发震断层破裂触发过程  

Rupture triggering process of Wenchuan earthquake seismogenic faults

作　　者：贺鹏超 沈正康[1,2] 

机构地区：[1]北京大学地球与空间科学学院地球物理系,北京100871 [2]美国加州大学洛杉矶分校地球与空间科学系

出　　处：《地球物理学报》2014年第10期3308-3317,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41090294)资助

摘　　要：2008年汶川大地震造成北川断裂、彭灌断裂、小渔洞断裂等多条断裂的破裂,呈现出复杂的破裂过程.对此,以往地震学的研究没有对于各个发震断层的破裂先后顺序给出充分论证.本文计算由于断层破裂在其他断层段上造成库仑应力的变化,根据其相互触发关系确定断层可能的破裂顺序.结果表明,各断裂带可能的发震顺序为:主震在北川断裂南端(小渔洞断裂以南的北川断裂虹口段)起始,造成北川断裂的后续段落龙门山镇—清平段和彭灌断裂同时破裂,进而触发小渔洞断裂发生破裂.The 2008 Wenchuan earthquake ruptured several faults simultaneously,such as the Beichuan,Pengguan,and Xiaoyudong faults,in a very complicated process.Previous studies however,have not fully addressed the issue of rupture sequence of these faults.This paper calculates the Coulomb failure stress changes on fault planes induced by preceding fault ruptures of various scenarios to test the rupture sequence.Results show that the earthquake started at the Hongkou segment of the southern part of the Beichuan fault,followed by the Longmenshan Town-Qingping segment of the northern Beichuan fault and the Pengguan fault,and the Xiaoyudong fault was triggered the last.

关 键 词：汶川地震 几何模型 同震破裂模型 破裂触发 库仑应力变化 

分 类 号：P315[天文地球—地震学]