2014年鲁甸地震(MS=6.5)静态库仑应力变化及其影响  

THE STATIC COULOMB STRESS CHANGE OF THE 2014 LUDIAN EARTHQUAKE AND ITS INFLUENCE ON THE AFTERSHOCKS AND SURROUNDING FAULTS

作　　者：缪淼[1,2] 朱守彪[1] 

机构地区：[1]中国地震局地壳应力研究所,地壳动力学重点实验室,北京100085 [2]中国地震局地球物理研究所,北京100081

出　　处：《地震地质》2016年第1期169-181,共13页Seismology and Geology

基　　金：地震动力学国家重点实验室开放基金项目(LED2012B01);中央级科研院所科研业务专项(ZDJ2014-01,ZDJ2013-21)共同资助

摘　　要：2014年8月3日在云南省昭通市鲁甸县发生了MS6.5左旋走滑型地震。为了解本次地震所造成的影响,文中利用前人反演的震源模型计算了主震产生的同震静态库仑应力变化,考察其对1个月内余震的触发效果以及对周围断层的影响。经计算后发现,82.43%的后续余震发生在静态库仑应力增加>0.01MPa的区域;说明大部分余震是由主震触发产生的。然后,使用周围断层作为接收断层,计算了鲁甸地震在周边断层上产生的库仑应力变化:发现昭通-鲁甸断裂(西支)的东北端及该断层东支的东北段库仑应力增大,发生地震的危险性会增大;而该区的大凉山断裂、莲峰断裂、则木河断裂、小江断裂和马边-盐津断裂的库仑应力都减小,即未来发生地震的危险性下降。另外,计算还发现,当选择最优破裂面作为库仑应力变化的投影面时,无论使用不同的震源模型还是改变有效摩擦系数,鲁甸地震对其后续余震始终具有较好的触发作用。On Aug. 3rd,2014,a MS6. 5 earthquake struck Ludian County,Yunnan Province. It is a typical left-lateral strike-slip event. With the purpose of understanding the influence of the Ludian earthquake,this paper firstly calculates the co-seismic Coulomb failure stress changes of the mainshock with the employment of the finite dislocation source model inversed by other researchers and studies the triggering effect to the aftershocks within a month. We find that 82. 43% of the aftershocks are located in the Coulomb stress increasing area（ ΔCFS 0. 01MPa）,therefore,most of the aftershocks are triggered by the mainshock. Then,regarding the surrounding active faults as the receive faults,the Coulomb stress changes of the mainshock are calculated to investigate the impact on the faults nearby. The result shows that only the northeast end of the west branch and northeast part of the east branch of Zhaotong-Ludian faults have been brought to failure. However,the other faults such as Daliangshan Fault,Lianfeng Fault,Zemuhe Fault,Xiaojiang Fault and Mabian-Yanjin Fault are unloaded after the Luidian event,so the possibility of future earthquake is decreased around these faults. Besides,when the optimal failure plane is chosen as the receive fault of the Coulomb stress changes,the Ludian earthquake always has good triggering effect to the aftershocks no matter which source models and effective friction coefficients are chosen.

关 键 词：2014年鲁甸地震 静态库仑应力变化 余震触发 

分 类 号：P315.727[天文地球—地震学]