2023年甘肃积石山M_(S)6.2地震随机有限断层三分向地震动模拟  

Three-component ground motion simulation for the 2023 M_(S)6.2 earthquake in Jishishan,Gansu,based on the stochastic finite-fault method

作　　者：毛岚 石玉成[1,2] 卢育霞 刘琨[1,3,4] MAO Lan;SHI Yucheng;LU Yuxia;LIU Kun(Lanzhou Institute of Seismology,CEA,Lanzhou 730000,Gansu,China;Gansu Earthquake Agency,Lanzhou 730000,Gansu,China;Key Laboratory of Loess Earthquake Engineering of CEA&Gansu Province,Lanzhou 730000,Gansu,China;Gansu Provincial Research Center for Conservation of Dunhuang Cultural Relics,Dunhuang 736200,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]甘肃省地震局,甘肃兰州730000 [3]中国地震局(甘肃省)黄土地震工程重点实验室,甘肃兰州730000 [4]甘肃省敦煌文物保护研究中心,甘肃敦煌736200

出　　处：《地震工程学报》2024年第4期778-790,共13页China Earthquake Engineering Journal

基　　金：国家自然科学基金联合基金项目(U22A20599);中国地震局地震预测研究所基本科研业务费项目(2020IESLZ03);中国地震局地震科技星火计划项目(XH24043A);甘肃省敦煌文物保护研究中心开放课题(GDW2021YB01);2024陇原青年创新创业人才(团队项目)。

摘　　要：2023年12月18日23时甘肃省临夏州积石山县发生M_(S)6.2地震,震中附近造成大量人员伤亡。基于不同数据和方法反演得到的震源破裂过程还有争议,为模拟此次地震的地面运动,分别采用SW倾向与NE倾向的震源破裂模型,利用随机有限断层法模拟三分向地震动。选取震中距约100 km内的57个触发强震台站,模拟其三分向加速度时程、速度时程及5%阻尼比拟加速度反应谱(PSA)。结果表明,模拟的峰值地面加速度(PGA)、峰值地面速度(PGV)能够体现地震动峰值的衰减规律,NE倾向的震源破裂模型会导致更大的地震动。模拟与观测记录的幅值接近、谱形相似,其中SW倾模型的PSA残差更小。基于三分向模拟地震动给出积石山M_(S)6.2地震的仪器烈度分布,SW倾向与NE倾向模型极震区烈度均达Ⅷ度,其中SW倾向模型与应急管理部发布的烈度图更加接近。积石山M_(S)6.2地震的模拟说明随机有限断层法可用于计算三分向地震动,并验证模拟输入震源、路径与场地参数的可靠性。At 23:00 on December 18,2023,an M_(S)6.2 earthquake occurred in Jishishan County,Linxia Prefecture,Gansu Province.A large number of casualties were found near the epicenter.The source rupture process due to inversion based on different data and methods remains controversial.The source rupture models dipping southwest and northeast were selected to simulate the ground motion of the earthquake,and the stochastic finite-fault method was employed to simulate three-component ground motions.The time-histories of three-component acceleration and velocity and 5%damped ratio pseudo-spectral acceleration(PSA)were simulated by selecting 57 triggering strong motion stations within 100 km of the epicenter.Results show that the simulated peak ground acceleration and peak ground velocity can demonstrate the attenuation law of peak ground motion,and the source rupture model dipping northeast leads to large ground motion.The amplitudes of simulated and observed PSAs are close,the spectral shapes are similar,and the PSA residual of the model dipping southwest is small.The instrument intensity distribution of the Jishishan M_(S)6.2 earthquake is obtained based on the simulated three-component records.The intensities of the two models in the meizoseismal area both reachⅧdegree,and the southwest-dipping model is closer to the intensity map released by the Ministry of Emergency Management.Simulation results of the Jishishan M_(S)6.2 earthquake reveal that the stochastic finite-fault method can be employed in the simulation of the three-component ground motion,and the reliability of the simulated source,path,and site parameters can be verified.

关 键 词：积石山M_(S)6.2地震 随机有限断层法 地震动模拟 地震烈度 强震记录 

分 类 号：P319.9[天文地球—固体地球物理学]