2023年9月9日摩洛哥M 6.9地震静态应力触发研究  

Static stress triggering of Morocco M 6.9 earthquake on 9 September 2023

作　　者：王润妍 万永魁 关兆萱 黄少华 顾培苑 宋泽尧 周明月 WANG Runyan;WAN Yongkui;GUAN Zhaoxuan;HUANG Shaohua;GU Peiyuan;SONG Zeyao;ZHOU Mingyue(School of Geosciences,Institute of Disaster Prevention,Sanhe 065201,Hebei,China;Langfang Key Laboratory of Earth Exploration and Information Technology,Sanhe 065201,Hebei,China)

机构地区：[1]防灾科技学院地球科学学院,河北三河065201 [2]廊坊市地球探测与信息技术重点实验室,河北三河065201

出　　处：《地质力学学报》2025年第2期223-234,共12页Journal of Geomechanics

基　　金：国家自然科学基金项目(42174074,41674055,42364005)。

摘　　要：库仑应力变化是研究地震触发效应和评估地震危险性的重要工具。为研究2023年9月9日摩洛哥M 6.9地震的静态库仑破裂应力对周围的触发作用,通过确定发震断层的几何形态和滑动性质,分析地震产生的同震位移场及地表应变场,评估主震对余震及周围断层的触发效应,揭示了该地震对区域地震活动性的影响。首先,利用“中心解”算法确定该地震可能发生的2个节面,并将当地应力场投影到这2个节面上,选择库仑应力较大的节面作为发震断层面;并基于统计公式,确定该发震断层面的滑动性质;在均匀弹性半空间理论模型下,构建地震作用下区域同震位移场及地表应变场。其次,假定接收断层的余震震源机制与主震一致,计算主震对余震的触发作用。最后,计算主震在周围断层上产生的库仑破裂应力变化,评估地震危险性。研究结果表明,震中物质向外涌出,南北两侧物质向内涌入,震中表现为隆升,南北两侧略微沉降;主震产生的静态库仑应力促进了大部分浅层余震的发生,大量余震处于库仑应力变化高值区;此外,南阿特拉斯断层西段—西南段、北阿特拉斯断层南段以及南苏斯断层西段的库仑应力高值区均超过0.01 MPa阈值,地震危险性极高,值得关注。[Objective]Coulomb stress change is an important tool for studying earthquake triggering effects and assessing seismic hazard.In order to study the triggering of the static Coulomb Failure Stress(CFS)of the M 6.9 earthquake in Morocco on September 9,2023,the study determined the geometric configuration and slip properties of the seismogenic fault,analyzed the co-seismic displacement field and surface strain field generated by the earthquake,and evaluated the triggering effects of the mainshock on aftershocks and surrounding faults,revealing the impact of this earthquake on regional seismic activity.[Methods]Using the"central solution"algorithm,two possible nodal planes of the earthquake were determined,and the local stress field was projected onto these two planes.The nodal plane with higher Coulomb stress was selected as the seismogenic fault plane(strike 253.44°,dip 45.43°,rake 81.05°).Based on statistical formulas,the slip properties of the seismogenic fault plane were determined.Under the homogeneous elastic half-space theoretical model,the co-seismic displacement field and areal strain field of the region were constructed.Subsequently,assuming that the focal mechanisms of the aftershocks on the receiver faults were consistent with the mainshock,the triggering effect of the mainshock on the aftershocks was calculated.Finally,the Coulomb stress changes induced by the mainshock on the surrounding faults were computed to assess the seismic hazard.[Results]The results show that the material at the epicenter moved outward,while the material on the north and south sides moved inward,resulting in uplift at the epicenter and slight subsidence on the north and south sides.The static Coulomb stress generated by the mainshock promoted the occurrence of most shallow aftershocks,with a large number of aftershocks located in areas of high Coulomb stress change.Additionally,the western and southwestern segments of the South Atlas Fault,the southern segment of the North Atlas Fault,and the western segment of the South Sou

关 键 词：摩洛哥M 6.9地震 应力触发 库仑应力 发震断层 

分 类 号：P315[天文地球—地震学]