2015年尼泊尔M_W7.9地震对强余震的触发作用和对周边断层的影响  

Strong Aftershocks Triggering and Stress Effect on Nearby Faults Induced by Nepal M_W7. 9 Earthquake in 2015

作　　者：黄禄渊[1,2] 杨树新[3] 陈连旺[3] 李玉江[3] 米琦[2] 

机构地区：[1]中国科学院计算地球动力学重点实验室,北京100049 [2]中国科学院大学地球科学学院,北京100049 [3]中国地震局地壳应力研究所,北京100085

出　　处：《地震研究》2016年第2期187-195,175,共9页Journal of Seismological Research

基　　金：深部探测技术与实验研究专项Sino Probe-06-03(国土资源部公益性行业科研专项201311181);中央级科研院所基本科研任务专项(ZDJ2013-22);2015年地震监测台网运行经常性项目联合资助

摘　　要：基于EDGRN/EDCMP程序,计算了尼泊尔M_W7.9地震引起的库仑应力变化对强余震的触发作用和对周边断层的加/卸载作用。结果显示:4月25日M_W6.7和4月26日M_W6.8强余震均受到明显触发作用,地震产生的应力场扰动有利于2015年5月12日M_W7.2强余震的发生。单独反演破裂模型和联合反演破裂模型的计算结果均显示:余震的分布和库仑应力变化的正值区有很好的对应关系,分别有85.5%和75.8%的余震落在库仑应力变化正值区。雅鲁藏布江缝合带西段的西侧受到超过10 k Pa的库仑应力加载。喀喇昆仑断裂、班公错怒江缝合带、格林错断裂的库仑应力加载约为1 k Pa。龙木错—邦达错断裂、玛尼玉树断裂以及嘉黎断裂受本次地震的影响较小。在震中的西北和东北方向,藏南典型南北向伸展构造受到了库仑应力加载作用,量值约为1 k Pa。Based on the EDGRN / EDCMP codes,we calculated the effect of the coulomb stress change induced by Nepal M_W7. 9 earthquake on strong aftershocks triggering and stress loading / unloading effect on nearby faults. The results showthat the M_W6. 7 strong aftershock on Apr. 25,and M_W6. 8 strong aftershock were significantly triggered,the co-seismic perturbed stress field contributes to the occurrence of M_W7. 2 aftershock on Apr. 12. The calculation result by using signal earthquake inversion rupture model and joint inversion rupture model of signal earthquake both showthat there were good corresponding relation between the positive zone of coulomb stress variation and the distribution of aftershocks,85. 5% and 75. 8% of aftershocks located at the positive coulomb stress zone respectively. The coulomb stress loading on west side of _Western Segment of Yarlung Zangbu River Suture Zone was larger than 10 k Pa. The Karakoram Fault,Bangong Nujiang Suture Zone and Gelincuo Fault were mainly under stress loading of about 1 k Pa. The Nepal M_W7. 9 earthquake has little influence on Longmucuo-Bangda,Mani-Yushu and Jiali Faults. In the northwest and northeast direction of the epicenter,the coulomb stress loading on typical S—N extensional structure in Southern Tibet was about 1 k Pa.

关 键 词：尼泊尔MW7.9地震 库仑应力变化 应力触发 周边断层 

分 类 号：P315.72[天文地球—地震学]