汶川8.0级地震和芦山7.0级地震对周边断层的影响  

Impact of the 2008 Wenchuan 8.0 and the 2013 Lushan 7.0 Earthquakes along the Longmenshan Fault Zone on Surrounding Faults

作　　者：徐晶[1] 邵志刚[2] 马宏生[3] 张浪平[2] 

机构地区：[1]中国地震局第二监测中心,陕西西安710054 [2]中国地震局地震预测研究所,北京100036 [3]中国地震局,北京100036

出　　处：《地震》2014年第4期40-49,共10页Earthquake

基　　金：十二五科技支撑专题(2012BAK19B01-04);震情跟踪专项工作任务(2014020101)共同资助

摘　　要：采用分层粘弹性介质模型,研究龙门山断裂带发生的两次大地震(2008年5月12日汶川8.0级和2013年4月20日芦山7.0级地震)的同震位错和震后粘滞松弛效应引起的周边断裂带上的库仑应力变化。结果表明,汶川8.0级地震同震和震后效应均引起了芦山7.0级地震震中位置的库仑应力增加,有利于芦山地震的发生;汶川和芦山地震的同震和震后效应引起的周边各断层上的累积库仑应力变化分布显示,这两次大地震引起了其间的破裂空段的库仑应力显著增加;此外,累积库仑应力显著升高的断裂还有:鲜水河断裂带中段、灌县—安县断裂北段、文县断裂的一部分、平武—青川断裂北段、略阳—勉县断裂。累积库仑应力显著降低的断裂有:马尔康断裂、岷江断裂南端、虎牙断裂、龙泉山断裂北端、北川—映秀断裂北段。Using multi-layered viscoelastic media, we calculated the Coulomb failure stress changes on the faults surrounding the Longmenshan fault zone which caused by co-seismic and post-seismic effects of the May 12, 2008 Wenchuan 8.0 earthquake and the April 20, 2013 Lushan 7.0 earthquake. The result shows that, both co-seismic effects and post-seis- mic effects of the Wenchuan 8.0 earthquake increased the Coulomb stress on the epicenter of the Lushan 7.0 earthquake, it benefitted the occurrence of the Lushan earthquake. The distribution of the Coulomb stress changes on the surrounding faults shows that, the two large earthquakes above mentioned caused significant increases of Coulomb stress on the segments between the two events. In addition, faults whose Coulomb stress increased sig- nificantly included the middle segment of Xianshuihe fault zone, the north segment of Guanxian--Anxian fault, the parts of Wenxian fault, the north segment of Pingwu-- Qingchuan fault and Lueyang--Mianxian fault. And faults whose Coulomb stress de- creased significantly included the Maerkang fault, the southern end of Minjiang fault, Huya fault, the northern end of Longquanshan fault and the north segment of Beichuan-- Yingxiu fault.

关 键 词：库仑破裂应力变化 断层相互作用 汶川8.0级地震 芦山7.0级地震 

分 类 号：P315.7[天文地球—地震学]