2023年2月6日土耳其M7.8和M7.5地震的触发关系  

Triggering relationship between M7.8 and M7.5 earthquakes in Turkey on February 6,2023

作　　者：刘博研 史保平 LIU BoYan;SHI BaoPing(National Institute of Natural Hazards,Ministry of Emergency Management of China,Beijing 100085,China;Kövesligethy RadóSeismological Observatory,Institute of Earth Physics and Space Science,Budapest 1112,Hungary;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]应急管理部国家自然灾害防治研究院,北京100085 [2]匈牙利地球物理和空间科学研究所,布达佩斯1112 [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球物理学报》2024年第12期4640-4650,共11页Chinese Journal of Geophysics

基　　金：应急管理部国家自然灾害防治研究院基本科研业务专项(ZDJ2017-09);国家留学基金;国家自然科学基金-联合基金项目(U23A2029);国家自然科学基金项目(U1939206)资助.

摘　　要：当地时间2023年2月6日4时17分在土耳其东南部的城市——埃尔津詹(Elazığ)发生了7.8级地震,震源深度约10 km,断层长度约为390 km.大约9 h后,发生了另一次强烈地震,震级为7.5级.这次地震震源深度为7.4 km,震中位于土耳其北部,距离之前的7.8级地震震中大约95 km.这两次强震的震中都位于东安纳托利亚断层系统上,且发震断层都表现为左旋走滑的特征.阿拉伯板块、欧洲板块、非洲板块和安纳托利亚地块的相对运动是导致此次地震发生的主要原因.本文使用有限断层滑移模型对土耳其M7.8地震后周边断层的库仑应力变化进行了计算和分析,基于库仑模型并结合断层的时空演化过程与断层的应力状态,探讨了M7.8地震对M7.5地震的触发关系,并计算得到从Sürgü断层遭受了0.2 MPa的静态库仑应力增加的扰动到宏观失稳所需的时间约为1.2~29.6 h,最多不超过290.1 h.实际上,7.5级地震发生在7.8级地震后约9 h,真实情况与我们计算得到的7.5级地震的发生时间较为吻合.At 4:17 AM local time on February 6,2023,a powerful 7.8 magnitude earthquake struck the city of Elazığin southeastern Turkey.The earthquake originated at a depth of approximately 10 km and had a fault length of about 390 km.Roughly 9 hours later,a magnitude 7.5 earthquake occurred approximately 95 km north of the epicenter of the M7.8 earthquake,with a focal depth of 7.4 km.Both seismic events were centered on the East Anatolian Fault System and exhibited characteristics of left-lateral strike-slip faults.The relative movement of the Arabian Plate,European Plate,African Plate and Anatolia Block were identified as the primary factors leading to these earthquakes.In this study,the Coulomb stress change on the surrounding faults following the M7.8 earthquake in Turkey was computed using the finite fault slip model.By employing the Coulomb model and considering the temporal and spatial evolution of the fault,as well as the stress state of the fault,this study investigates the triggering relationship between the M7.8 earthquake and the subsequent M7.5 earthquake.Our calculations indicate that it would take approximately 1.2 to 29.6 hours,with a maximum of no more than 290.1 hours,for the Sürgüfault to undergo macroscopic instability when subjected to a static Coulomb stress increase of 0.2 MPa.Notably,the M7.5 earthquake occurred roughly 9 hours after the M7.8 earthquake,closely aligning with our calculated occurrence time.This finding highlights a strong agreement between our calculations and the actual occurrence of the M7.5 earthquake.

关 键 词：土耳其M7.8地震 库仑应力变化 地震触发 时空演化过程 

分 类 号：P315[天文地球—地震学]