黄土高原两次历史地震强地震动模拟  

Strong ground motion simulation of two historical earthquakes in the Loess Plateau

作　　者：席书衡 李孝波[1,2] 宣雨童 王天虎 柳耀阔 XI ShuHeng;LI XiaoBo;XUAN YuTong;WANG TianHu;LIU YaoKuo(Institute of Disaster Prevention,Sanhe 065201,China;Hebei Key Laboratory of Earthquake Disaster Prevention and Risk Assessment,Sanhe 065201,China)

机构地区：[1]防灾科技学院,三河065201 [2]河北省地震灾害防御与风险评价重点实验室,三河065201

出　　处：《地球物理学进展》2023年第6期2451-2463,共13页Progress in Geophysics

基　　金：国家自然科学基金(U1939209);中央高校基本科研业务费专项(ZY20230309)联合资助。

摘　　要：强地震动模拟是合理开展历史地震震害机理研究的基础.基于随机有限断层法,综合考虑震源、传播路径和场地条件的影响,分别进行了1654年天水地震和1920年海原地震强震动模拟.结果表明:(1)天水、海原地震PGA的最大值分别为2600 cm/s^(2)和3700 cm/s^(2),PGA等值线沿发震断层对称展布,分布范围具有随PGA值增大而逐渐减小的趋势;(2)两次地震PGV的变化规律与PGA相似,等值线的疏密程度与断层距成反比;(3)天水、海原地震SI的最大值分别为150 cm/s和200 cm/s,等值线与PGA、PGV的关联性较强;(4)与现有等震线图相比,两次地震的II均展现出了良好的吻合度.作为合理确定地震动输入的一种途径,本文可为历史地震强地震动(高频)的快速模拟提供参考.Strong ground motion simulation is the basis of reasonable research on historical earthquake damage mechanisms.Based on the stochastic finite fault method,the influences of the source,propagation path and site condition are comprehensively considered,and strong motion simulations of the Tianshui earthquake in 1654 and the Haiyuan earthquake in 1920 are performed.The Peak Ground Acceleration(PGA),Peak Ground Velocity(PGV),maximum horizontal Spectral Intensity(SI)and Chinese instrumental seismic intensity(II)of the two historical earthquakes are determined.Results reveal that:(1)The maximum PGA values of the Tianshui and Haiyuan earthquakes are 2,600 cm/s^(2) and 3,700 cm/s^(2),respectively;moreover,the PGA isolines are symmetrically distributed along the seismogenic fault,and the distribution range exhibits a gradually decreasing trend with the increase in the PGA value.(2)The PGV value of the Tianshui and the Haiyuan earthquakes is between 5 cm/s and 90 cm/s and between 5 cm/s and 120 cm/s,respectively.Furthermore,the pattern of change of PGV in the two earthquakes is similar to that of PGA,and the density of the isolines is inversely proportional to the fault distance.(3)The maximum values of SI for the Tianshui and Haiyuan earthquakes are 150 cm/s and 200 cm/s,respectively;moreover,the correlation between isoline,PGA and PGV is strong.(4)The maximum intensity corresponding to the Tianshui earthquake II is intensity X,and that corresponding to the Haiyuan earthquake II is intensity XI.Compared with the existing isoseismal map,the II values of the two earthquakes are consistent.Moreover,the fitting results of the instrumental seismic intensity maps obtained from the two earthquake simulations are within the range of high-intensity areas and are applicable to ground motion simulations with Intensity VII and above.Thus,to reasonably determine the input of ground motion,this study can be a reference for the rapid simulation of the strong ground motion(high frequency)of historical earthquakes.

关 键 词：地震动模拟 随机有限断层法 1654年天水地震 1920年海原地震 黄土高原 

分 类 号：P315[天文地球—地震学]