土耳其帕扎尔哲克M7.8地震构造背景与地表破裂特征  

The tectonic setting and surface rupture characteristics of the M7.8 Pazarcik earthquake in Turkey

作　　者：李传友[1] 张会平[1] 李俊杰 俞晶星[1] 任治坤[1] 马字发 Murat Tamer 王世广 龚正[2] 周晓成[3] 徐岳仁[3] 梁朋[3] LI ChuanYou;ZHANG HuiPing;LI JunJie;YU JingXing;REN ZhiKun;MA ZiFa;Murat Tamer;WANG ShiGuang;GONG Zheng;ZHOU XiaoCheng;XU YueRen;LIANG Peng(State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China)

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029 [2]中国地震局地球物理研究所,北京100081 [3]中国地震局地震预测研究所,北京100036

出　　处：《地球物理学报》2025年第4期1304-1314,共11页Chinese Journal of Geophysics

基　　金：中央级公益性科研院所基本科研业务专项(IGCEA2302);国家自然科学基金(42072250);第二次青藏高原综合科学考察研究项目(2019QZKK0901)资助。

摘　　要：2023年2月6日在土耳其东南部发生了一次M7.8双震型地震序列.其中第一次主震——帕扎尔哲克7.8级地震发生在东安纳托利亚断裂(EAF)上,是该断裂历史上记载的最大的地震事件之一.综合发震断裂的构造背景和历史地震的分析结果表明,此次地震发生在EAF的地震空区.作为土耳其地区主要活动断层之一,东安那托利亚断裂充当了阿拉伯板块和安纳托利亚板块之间长约580 km的板块边界.与位于安那托利亚板块北部边界,且经历了一系列破坏性大地震的北安那托利亚断裂(NAF)不同,EAF在过去一个世纪中仅经历了小到中等规模的事件.该断裂东北段以发生中等强度的地震为特征,过去两百年间该断裂上的破坏性地震主要发生在这一段.而野外调查显示,该次帕扎尔哲克7.8级地震的地表破裂则主要沿着EAF西南段的三个断裂分段及震中附近的一条分支断裂发生,地表破裂总长约300 km.地表破裂表现为典型的走滑型特征,包括右阶雁列的裂缝、陡坎、鼓包、凹陷和挤压脊等,以及左旋位错的线性地貌等.位错地貌和断层面擦痕显示断裂以左旋走滑运动为主,最大同震左旋位移为6.4m.破裂长度和最大水平位移均为该断裂上有记录的同震地表破裂中的最高值.根据野外地质调查结果,并综合已有的地震学、形变观测等资料判定,本次帕扎尔哲克7.8级地震由一条分支断裂(纳尔利断裂)的活动发起,其后触发主断裂EAF发生破裂,是一次多段参与的破裂事件.该事件显示了典型的破裂级联现象,即一个事件使多个相邻的断层段同时发生破裂.总体看,EAF是一条南北存在活动性差异的复杂断裂,未来应特别关注该断层的东北部,因为其具有几个分段同时破裂形成大规模级联事件的可能性.On February 6,2023,a doublet earthquake sequence(two M7.8 earthquakes)occurred in southeastern Turkey.The first mainshock,the M7.8 Pazarcik earthquake,took place on the East Anatolian Fault(EAF),being one of the largest recorded seismic events on this fault.The comprehensive analysis of tectonic background of the seismogenic fault and historical earthquakes shows that this earthquake happened in the seismic gap of the EAF.Serving as one of the major active faults in Turkey,the EAF forms an~580-km-long plate boundary between the Arabian and Anatolian plates.In contrast to the North Anatolian Fault(NAF)bounding the northern margin of the Anatolian plate and experiencing a series of destructive earthquakes,the EAF has only undergone small to moderate events in the past century.The northeast segment of this fault are distinguished by moderate earthquakes and responsible for the most destructive earthquakes in the past two hundred years.However,field investigations indicate that the surface ruptures of the M7.8 Pazarcik earthquake mainly occurred along the three segments of the southwestern EAF and a branch fault near the epicenter,with a total surface rupture length of approximately 300 km.The surface ruptures exhibit typical strike-slip faulting features,including right-stepping echelon cracks,scarps,moletracks,depressions,pressure ridges,and left-lateral offset linear landforms.Faulted landforms and striations on the fault plane indicate a predominant left-lateral strike-slip motion,with a maximum co-seismic left-lateral displacement of 6.4 m.The co-seismic surface rupture length and maximum horizontal displacement are the highest values recorded on this fault.Based on field geological surveys and combined with the existing seismological and geodetic observation data,it is determined that the M7.8 Pazarcik earthquake was initiated on a secondary fault(the Narli fault),triggering the main rupture of the EAF.This was a multi-segment rupture event,which shows typical rupture-cascading that one event brought several ne

关 键 词：帕扎尔哲克7.8级地震 发震构造 东安纳托利亚断裂 历史地震 同震地表破裂 

分 类 号：P315[天文地球—地震学]