九寨沟Ms 7.0级地震的左旋走滑作用与动力机制  

Left-lateral strike-slip effect and dynamic mechanism of the Jiuzhaigou Ms 7.0 earthquake in the eastern margin of Tibetan Plateau,China

作　　者：李勇[1] 邵崇建 李芃宇 周荣军[3] 刘玉法[3] 张威[3] 马超[3] 颜照坤[1] 闫亮[1] 王伟明 

机构地区：[1]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059 [2]四川省蜀通岩土工程公司,成都610036 [3]四川省地震局,成都610041 [4]华蓥市地质环境监测站,四川华蓥638600

出　　处：《成都理工大学学报（自然科学版）》2017年第6期641-648,共8页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金项目(40841010;40972083;41172162;41372114;41340005);国土资源部地质调查项目(1212011121268);油气藏地质及开发工程国家重点实验室研究项目(SK-0801)

摘　　要：2017年8月8日四川九寨沟发生的Ms 7.0级地震是继2008年汶川Ms 8.0地震、2013年芦山Ms 7.0级地震后在青藏高原东缘发生的又一次强震。本文通过综合分析九寨沟Ms 7.0级地震及历史地震的震源机制解、余震和历史地震分布、区域应力场、活动断层等资料,来揭示九寨沟地震的发震构造与动力机制。初步研究结果表明:(1)此次地震的震中位于塔藏断裂、岷江断裂和虎牙断裂之间的交汇区,显示活动断裂的交汇区对此次地震的发生具有控制作用;(2)发震断裂为虎牙断裂,断裂走向为北西西向,倾向南西,倾角较陡,属于高倾角左旋走滑型地震;(3)震中位于虎牙断裂北段的北部地震空区,充填了1973年和1976年4次大于Mw6.0级地震空区;(4)此次地震位于2008年汶川Ms 8.0级地震的库仑应力增加区,应是汶川地震的应力传递和触发的结果;(5)此次地震位于巴颜喀拉块体的东北部顶角区,青藏高原东缘下地壳流向北东方向的挤出是驱动此次地震的动力机制。The Jiuzhaigou Ms 7. 0 earthquake in 2017 occurred in the eastern margin of the Tibetan Plateau after the Wenchuan Ms 8. 0 earthquake in 2008 and the Lushan Ms 7. 0 earthquake in 2013. Comprehensive analysis ofseismic source mechanism solution of the earthquake, historical earthquakes, distribution of aftershocks and historical earthquake,regional stress field,active faults are carried out in order to unravel the seismogenic structures and dynamic mechanism of the Ms 7. 0 Jiuzhaigou earthquake. The preliminary research shows that:( 1)The epicenter of the earthquake is located in the intersection area among the Tazan fault,the Minjiang fault and the Huya fault,and the intersection position of active faults has a controlling effect on the occurrence of the strong earthquake.( 2) The seismogenic fault of the earthquake is Huya fault a NNW-trending fault with a large tilting angle,characteristic of a high dipping angle,sinistral strike-slip earthquake.( 3) The earthquake is located in seismic gap in the northern part of the northern segment of the Huya fault,filled the seismic gap of over Mw 6. 0 earthquakes in 1973 and 1976.( 4) The earthquake is located in the Coulomb stress increase area of Wenchuan Ms8. 0 earthquake,and it is likely that the earthquake is the results of stress transmission of Wenchuan earthquake.( 5) The earthquake is located in the northeastern part of the Bayankala Block,and the dynamic mechanism of the earthquake is the northeastward extrusion of lower crustal flow in the eastern margin of the Tibetan Plateau.

关 键 词：青藏高原东缘 九寨沟地震 左旋走滑 动力机制 

分 类 号：P315.2[天文地球—地震学]