昌马MS7.6地震三维同震形变场数值模拟及库仑应力触发研究  

Numerical simulation of 3D coseismic deformation field and Coulomb stress triggering Changma M S7.6 earthquake

作　　者：朱俊文 蔡艺萌 张波 姚赟胜 ZHU Junwen;CAI Yimeng;ZHANG Bo;YAO Yunsheng(Gansu Lanzhou Geophysics National Observation and Research Station,Lanzhou 730000,Gansu,China)

机构地区：[1]甘肃兰州地球物理国家野外科学观测研究站,甘肃兰州730000

出　　处：《地震工程学报》2023年第3期598-605,共8页China Earthquake Engineering Journal

基　　金：甘肃省地震局地震科技发展基金项目(2021M4);甘肃省地震局创新团队项目(2019TD0101);中国地震局地震预测研究所基本科研业务费(2021IESLZ06)。

摘　　要：1932年12月25日,甘肃玉门市昌马镇附近发生MS7.6地震(震中:39.70°N,96.70°E),此次地震是继1920年海原MS8.5地震、1927年古浪MS8.0地震之后青藏高原东北缘祁连山—河西走廊地震带内的又一强震。这组大地震活动无论在时间序列上还是在空间序列上都极其罕见,引起了众多国内外学者的广泛关注,普遍认为是一次陆内地震活动沿相关断裂带由东向西迁移的典型样例。基于PSGRN/PSCMP程序,以前人地表地质调查相关结果为约束,利用弹性位错理论获取昌马地震断层破裂模型,以此为基础,基于黏弹性半空间分层模型模拟计算昌马地震产生的地表同震三维形变场。通过研究单次地震与地震叠加的库仑应力变化对后续地震的触发关系,分别对海原地震、古浪地震以及它们的叠加对昌马地震的触发作用进行研究。结果表明:海原地震、古浪地震以及它们的叠加均未超过可能触发地震的经验阈值,故认为昌马地震可能不受海原地震和古浪地震所造成的库仑应力变化的影响。此研究可为利用实际形变解释昌马地震的孕震过程研究提供理论依据。On December 25,1932,an M S7.6 earthquake occurred near Changma Town,Yumen City,Gansu Province(epicenter:39.70°N,96.70°E).This movement is another strong earthquake along the Qilian Mountains-Hexi Corridor seismic zone in the northeast margin of the Tibetan Plateau following the Haiyuan M S8.5 earthquake in 1920 and the Gulang M S8.0 earthquake in 1927.This group of large earthquakes,which is extremely rare in terms of time and space,has attracted extensive attention from many scholars.It is generally believed to be a typical example of an inland seismic activity migrating from east to west along the related fault zone.Using the program PSGRN/PSCMP and relevant results of previous geological surveys,this study established the fault rupture model of the Changma earthquake on the basis of elastic dislocation theory.The 3D coseismic deformation field of the surface generated by the Changma earthquake was simulated and calculated using the viscoelastic half-space layered model.The triggering effects of the Coulomb stress changes of the Haiyuan earthquake,the Gulang earthquake,and their superposition on the Changma earthquake were also studied.Results show that the Haiyuan earthquake,Gulang earthquake,and their superposition do not exceed the empirical threshold of possible triggering earthquakes.Therefore,the Changma earthquake may not have been affected by the Coulomb stress changes caused by Haiyuan and Gulang earthquakes.The simulation results in this work can provide a theoretical basis for explaining the seismogenic process of the Changma earthquake.

关 键 词：昌马地震 三维同震形变 库仑应力变化 应力触发 

分 类 号：P315.2[天文地球—地震学]