基于黏弹性模型的苍山地震库仑应力变化研究  

Coulomb Stress Changes Induced by Cangshan M_S5.2 Earthquake Based on Visco-elastic Model

作　　者：刘方斌[1] 曲均浩[1] 田兆阳[1] 刘承雨[1] 

机构地区：[1]山东省地震局,山东济南250014

出　　处：《地震工程学报》2017年第1期133-140,共8页China Earthquake Engineering Journal

基　　金：山东省自然科学基金(ZR2014DQ019);山东省地震局青年科研基金(JJ1506Y);中国地震局星火计划项目(XH16025)

摘　　要：采用多层黏弹性模型,计算郯城地震和苍山地震引起的同震及震后黏弹松弛库仑应力变化,讨论这两个地震之间的触发关系、苍山地震对余震分布及周围地区应力变化的影响。结果表明:(1)郯城地震对苍山地震的发生有一定的抑制作用;(2)苍山地震的大部分余震分布在库仑应力增加区域,库仑应力变化值为0.08~0.12bar,且余震主要分布在8~14km处的断层面上;(3)安丘—莒县断裂的东北部、苍尼断裂的中段、凫山断裂的东段以及韩庄断裂、峄城断裂位于库仑应力增加区,均存在较强的地震危险性。The Cangshan Ms 5.2 earthquake, which occurred on September 20, 1995, was one of the largest earthquakes of the past century in southern Shandong Province and inflicted huge financial losses. As it was also a significant example of the new active phase in North China, it is necessary to determine the seismicity and potential seismic hazard in the areas affected by this earthquake. Earthquakes are natural phenomena caused by fault movement when stress accumulates to a certain extent. Coulomb stress change occurs due to coseismic dislocations and visco-elastic relaxation after an earthquake. Research shows that a small change in the Coulomb stress can trigger an earthquake. In order to calculate the Coulomb stress changes of the Cangshan earthquake and their influence on surrounding faults, in this paper, we use field investigation results in a multi-layered visco-elastic model to determine the Coulomb stress changes from the coseismic dislocations and visco-elastic relaxation following the Tancheng and Cangshan earthquakes. We also discuss the triggering relationship between the two earthquakes, the influence of the aftershock distribution features of the Cangshan earthquake, and the influence of stress on the surrounding area. The results show that; （1） The Tancheng earthquake changed the conditions of failure in Cangshan, and the Cangshan earthquake wasdelayed by the Coulomb stress change （--3.23 bar） caused by the Tancheng earthquake in this area. （2） By analyzing the relationship between the Coulomb stress changes caused by the Cangshan earthquake and the aftershocks distribution, we found most of the aftershocks to have been located in regions where the Coulomb stress increased 0.08~0.12 bar. （3） With respect to visco-elastic relaxation, the calculation results show the Tancheng and Cangshan earthquakes to have had a significant influence on nearby faults. The northeast Anqiu--Junxian fault, the middle of the Cangni fault, the east Fushan fault, the Hanzhuang fault, and the Yicheng fault are a

关 键 词：郯城地震 苍山地震 黏弹性 库仑应力变化 地震危险性 

分 类 号：P315[天文地球—地震学]