2023年甘肃积石山M_(S)6.2地震精定位及发震构造研究  

Precise location of the 2023 Jishishan M_(S)6.2 earthquake in Gansu Province and its seismogenic structure

作　　者：陈科睿 陈继锋[1,2] 尹欣欣 CHEN Kerui;CHEN Jifeng;YIN Xinxin(Lanzhou Institute of Seismology,CEA,Lanzhou 730000,Gansu,China;Gansu Lanzhou Geophysics Observation and Research Station,Lanzhou 730000,Gansu,China)

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]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》2024年第4期932-941,共10页China Earthquake Engineering Journal

基　　金：中国地震局地震预测研究所基本科研业务费专项(2023IESLZ02);甘肃省科技计划项目(23JRZA334);国家自然科学基金面上项目(42371404)。

摘　　要：采用双差定位的方法,对2023年12月18日甘肃省积石山县M_(S)6.2地震的余震(震后一周)进行重定位,最后获得438个地震事件(包含主震)的位置。定位结果显示余震主要呈NNW向分布,长度约为16 km;主震位于余震带的中央偏东北处,余震分布与拉脊山断裂近似平行,与主震的震源机制解吻合;余震的震源深度主要集中在6.5~12 km,主震深度为11.5 km。从沿断裂走向的剖面可以观察到,此次地震的浅地表余震事件较少,因此未造成明显的地表破裂。对发震断裂的分析表明,拉脊山断裂带的走滑速率较低,这可能代表其处于强锁定阶段。此外,地震聚类分析表明,尽管北拉脊山断裂是主要发震断裂,南拉脊山断裂与此次地震的发震构造也存在紧密联系。We analyzed the aftershocks of the Jishishan M_(S)6.2 earthquake,which occurred in Gansu Province on December 18,2023.These aftershocks,which correspond to the shocks felt for one week after the main shock,were relocated using the double-difference algorithm.The aim of this study was to accurately determine the precise location of the 438 seismic events,including the mainshock.The relocation results show that the aftershocks were primarily distributed along the NNW direction,with a length of approximately 16 km.The main shock was located in the northeast direction of the center of the aftershock zone,and the distribution of aftershocks was roughly parallel to the Lajishan fault,indicating a correspondence with the focal mechanism of the mainshock.The focal depths of the aftershocks ranged from 6.5 to 12 km,and the mainshock was relocated at a depth of 11.5 km.As seen from the profile along the rupture strike,the earthquake caused a small number of shallow surface aftershock events and did not result in surface ruptures.An analysis of the seismogenic fault in the present study indicates that the Lajishan fault zone exhibits a modest strike-slip rate,indicating that it is in a strong locking state.Furthermore,the analysis results derived using the clustering method showed that although the north Lajishan fault is the main seismogenic fault,the south Lajishan fault is also closely related to the earthquake.

关 键 词：积石山M_(S)6.2地震 双差定位 震源机制 发震构造 时空演化 

分 类 号：P315[天文地球—地震学]