基于随机有限断层法的泸定6.8级地震强地面运动场重建  

Reconstruction of Strong Ground Motion of the Luding M_(s)6.8 Earthquake in 2022 Based on Stochastic Finite Fault Method

作　　者：宣雨童 李孝波[1,2] 欧阳刚垒 席书衡 XUAN Yutong;LI Xiaobo;OUYANG Ganglei;XI Shuheng(Institute of Disaster Prevention,Sanhe 065201,China;Hebei Key Laboratory of Earthquake Disaster Prevention and Rish Assessment,Sanhe 065201,China)

机构地区：[1]防灾科技学院,河北三河065201 [2]河北省地震灾害防御与风险评价重点实验室,河北三河065201

出　　处：《防灾科技学院学报》2023年第4期14-26,共13页Journal of Institute of Disaster Prevention

基　　金：国家自然科学基金(U1939209、51808118);中央高校基本科研业务费专项(ZY20230309)。

摘　　要：基于随机有限断层法开展泸定6.8级地震强地震动模拟,并通过实际强震记录校核,重建了泸定地震的强地面运动场。结果表明:(1)震中距80km以内,大部分模拟峰值地面加速度值与实际值较为接近,峰值地面加速度差值最小为0.58gal;(2)与低频段相比,高频段加速度反应谱的模拟效果较好,与实际反应谱的吻合度更高;(3)模拟峰值地面加速度(PGA)、峰值地面速度(PGV)、谱烈度(SI)及仪器地震烈度(II)的最大值分别为433gal、30cm/s、34cm/s、8.5,除II的模拟结果未展现Ⅸ度区外,各地震动参数均沿断层延伸方向呈对称分布,且在宏观形态上与地震烈度图的相似性较强;(4)与实际地震烈度图相比,重建的强地面运动场可有效预估地震烈度Ⅶ~Ⅸ度区的分布范围。作为合理确定地震动输入的一种途径,研究结果不仅可为泸定地区的抗震设防工作提供技术支撑,也可为特定地震强地震动(高频)的快速模拟提供参考。The strong ground motion of the Luding M_(S)6.8 earthquake in 2022 was simulated by the stochastic finite fault method,and the strong ground motion field was reconstructed through calibration of the actual strong earthquake recordings.The results show that:(1)Most of simulated PGA values are closer to actual PGA values,and the smallest difference between the simulated and actual PGA values is 0.58gal in the area within 80km from the epicentre.(2)Compared with simulation results of acceleration response spectra in low-frequency band,simulation results of acceleration response spectra in high-frequency band are better and better agree with the actual response spectra.(3)The maximum values of simulated PGA,PGV,SI and I_(I) are 433gal,30 cm/s,34 cm/s and 8.5,respectively.Except for the simulation result of I_(I) does not showed the IX-degree zone in the PGA strong ground motion field,ground motion parameters are symmetrically distributed along the extension direction of the fault,whose macroscopic form is more similar with the seismic intensity map.(4)Compared with the actual seismic intensity map,the reconstructed strong ground motion field can efficiently predict the distribution range of the seismic intensity zoneⅦ-IX.As a method to reasonably determine the ground motion input,the results in this study can not only provide technical support for the seismic fortification work of the Luding area but also provide a reference for the rapid simulation of strong ground motion(high-frequency)for specific earthquakes.

关 键 词：泸定6.8级地震 随机有限断层法 强地面运动场 加速度时程 反应谱 

分 类 号：P315.914[天文地球—地震学]