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Title:: The Coulomb Stress Evolution after the 1976 Tangshan Strong Earthquake Swarm and Its Relationship with the 2020 Guye M5.1 Earthquake

作者:: 朱琳¹; 李腾飞²; 石富强¹; 石军¹; 邵辉成¹; (1.陕西省地震局,陕西西安 710068; 2.中交公路规划设计院有限公司,北京 100088)

Author(s):: ZHU Lin¹; LI Tengfei²; SHI Fuqiang¹; SHI Jun¹; SHAO Huicheng¹; (1.Shaanxi Earthquake Agency,Xi'an 710068,Shaanxi,China)(2.Highway Consultants CO.Ltd.,China Communications Construction Co. Ltd.,Beijing 100088,China)

Keywords:: Guye earthquake; Tangshan earthquake; Coulomb stress; Burgers rheological model

摘要:: 采用能够综合协调长期变形和震后短期变形的Burgers流变模型,模拟了1976年唐山强震群引起的震后形变场以及同震和震后库仑应力变化。结果显示:1976年唐山强震群中主震的两个破裂面以及滦县和宁河两次强余震均对2020年古冶5.1级地震表现为库仑应力加载。岩石圈粘弹性松弛效应引起的库仑应力变化显示,震后15年前后,库仑应力演化状态呈现显著的差异性:震后15年内,库仑应力变化剧烈; 而震后15年后,库仑应力呈现缓慢的稳定增加状态。该过程与唐山强震群余震区地震活动过程相似,可能暗示1976年唐山强震群余震区应力调整过程已基本稳定。

Abstract:: Based on the Burgers rheological model which is absorbed in the synthetic simulation of long-term tectonic deformation and short-term postseismic deformation,we simulated the co- and postseismic deformation and the related coseismic and postseismic Coulomb stress evolution that caused by the 1976 Tangshan strong earthquake swarm.Our results show that the two segements of mainshock rupture and the two strong aftershocks in Luanxian and Ninghe of 1976 Tangshan strong earthquake swarm could enhance the Coulomb stress on the rupture plane of the 2020 Guye M5.1 earthquake.The temporal evolution of the lithosphere postseismic relaxation Coulomb stress show that,before and after the postseismic 15 years,the evolution state of Coulomb stress shows significant difference.Within 15 years after the Tangshan earthquake,the Coulomb stress evolution is dramatic,and while after 15 years,it is increased steady and slowly.This pattern is similar to the seismicity in the aftershock zone of Tangshan strong earthquake swarm.This may indicated that the dynamic stress adjustment in the aftershock zone of Tangshan strong earthquake swarm have been stabilization.