文章摘要

文章信息/Info

Title:: Seismogenic Structure of the 2021 Yangbi,Yunnan M_S6.4 Earthquake and Earthquake Risk Analysis in the Epicenter Area

Author(s):: HE Suge; ZHOU Qingyun; LIU Zifeng; (Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)

Keywords:: the Yangbi M_S6.4 earthquake; seismogenic fault; earthquake risk; earthquake prediction

摘要:: 通过野外调查,结合震源机制解和余震分布情况,认为2021年漾濞M_S6.4地震发震断裂不是维西—乔后断裂的主断裂,而是一条NW走向的断裂。收集了震中周边活动断裂、b值、P波速度和深部滑动速率等资料,对漾濞周边地区的地震风险进行了评估。分析认为,漾濞M_S6.4地震发生于P波低速区域,未来原震区发生更大地震的可能性较低; 维西—乔后断裂北段和南段断层性质具有较大差异,震中附近的断裂南段活动性相对较弱; 震后漾濞及周边地区的地震高风险区主要分布在乔后镇及附近区域(龙蟠—乔后断裂南端)、鹤庆西区域(丽江—小金河断裂南西段),未来应重点关注。

Abstract:: The 2021 Yangbi M_S6.4 earthquake is the first M≥6 event since the 2014 Jinggu M_S6.6 earthquake in Yunnan Province.Through field investigation of the Yangbi earthquake,along with its focal mechanism and aftershocks’ distribution,we considered that the seismogenic fault of this earthquake is not the Weixi-Qiaohou Fault,but a NW trending buried fault.According to the collected data of active faults,b-value,P-wave velocity and slip rate of the faults in the deep around the epicenter,we assessed the seismic risk in Yangbi area and its vicinity.We concluded that the Yangbi earthquake occurred in the low P-wave velocity area,so it is less likely to form a larger earthquake in this area in the future.The north and south segments of the Weixi-Qiaohou Fault are of great differences,The activity of the south segment is relatively weak.The high earthquake risk zones in the Yangbi area are Qiaohou Town and its nearby areas in the South of the Longpan-Qiaohou Fault,and the Western Heqing County in the southwest section of the Lijiang-Xiaojinhe Fault,which should be paid more attention to in the future.