泸定地震诱发磨西断裂局部应力场偏转的离散元模拟分析  

Discrete Element Simulation Analysis of Local Stress Field Deflection of Moxi Fault induced by the Luding,Sichuan M_(S)6.8 Earthquake in 2022

作　　者：曾扬农 苏占东 孙进忠[3] 张建勇 唐磊 周剑 张涛 吴雪丽 ZENG Yangnong;SU Zhandong;SUN Jinzhong;ZHANG Jianyong;TANG Lei;ZHOU Jian;ZHANG Tao;WU Xueli(Department of Geological Engineering,Institute of Disaster Prevention,Sanhe 065201,China;Hebei Key Laboratory of Earthquake Disaster Prevention and Risk Assessment,Sanhe 065201,China;College of Engineering and Technology,China University of Geosciences,Bejing 100083,China;China Earthquake Networks Center,China Earthquake Administration,Beijing 100045,China;Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]防灾科技学院地质工程学院,河北三河065201 [2]河北省地震灾害防御与风险评价重点实验室,河北三河065201 [3]中国地质大学(北京)工程技术学院,北京100083 [4]中国地震台网中心,北京100045 [5]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《防灾科技学院学报》2022年第4期56-66,共11页Journal of Institute of Disaster Prevention

基　　金：中央高校基本科研业务费专题研究重点项目(ZY20215113);国家自然科学基金(41807270)。

摘　　要：基于磨西断裂附近的姑咱台站和天全台站YRY-4型四分量钻孔应变仪的监测数据,采用PFC^(2D)(5.0)离散元软件模拟泸定地震时磨西断裂局部应力场最大主应力方向的时空演化特征。模拟结果表明,地震前后姑咱台站和天全台站的最大水平主应力(S_(H))方向出现不同程度偏转。模拟结果与现场观测结果基本吻合,泸定地震时断裂的左旋错动会引起地壳浅表层产生压缩应力区和拉伸应力区,而且压缩应力区的偏转角变化值(Δθ)整体呈现逆时针偏转,拉伸应力区的Δθ整体呈现顺时针偏转,距离断裂越远,局部应力场偏转角越小。Based on the monitoring data of YRY-4 four component borehole strain gauges at Guzan and Tianquan stations near the Moxi fault,we simulated the spatial-temporal evolution characteristics of the maximum principal stress direction of the local stress field of the Moxi fault induced by the Luding,Sichuan MS6.8 earthquake in 2022 by use of PFC^(2D)5.0 discrete element software.The simulation results show that the maximum horizontal principal stresses(S_(H))at the Guzan and Tianquan stations deflected to varying degrees before and after the earthquake,and the simulated results are largely consistent with the field observations.During the Luding earthquake,the left-lateral dislocation of the fault induced both compression stress zone and tensile stress zone in the shallow crust,and the variation value of the deflection angle of the compression stress zone(Δθ)showed an anticlockwise deflection on the whole,while the whole tensile stress zone deflects clockwise.Besides,the farther away from the fracture,the smaller the deflection angle of the local stress field.

关 键 词：泸定地震 磨西断裂 局部应力场 应力偏转角 PFC^(2D) 

分 类 号：P315.72[天文地球—地震学]