地球与行星物理论评（中英文）2026，Vol.57Issue(6)：700-713,14.DOI:10.19975/j.dqyxx.2026-006
基于随机有限断层法的2025年西藏定日MW7.1地震强地震动模拟
Simulation of strong ground motions for the MW7.1 Dingri,Xizang earthquake in 2025 using the stochastic finite-fault methodology
摘要
Abstract
On January 7,2025,anMW 7.1 earthquake struck Dingri,Xizang,causing severe engineering damage in the epicentral area.To scientifically reconstruct the ground motion impact field of this event,a strong ground motion simulation model was established based on the stochastic finite-fault method,incorporating the inverted source rupture process.A systematic study on key sensitive parameters was conducted:by comparing the mean values of 30 stochastic realizations with the pseudo-acceleration spectra(PSA)recorded at early warning stations,the op-timal stress drop was determined to be 10.0 MPa;meanwhile,the high-frequency attenuation parameter(κ)was es-timated as 0.032 6 based on the negative correlation between its median value and site source,path,and site parameters,a reliability test was performed using observational data from the National Seis-mic Intensity Management and Early Warning Project.Consequently,the gridded distributions of peak ground ac-celeration(PGA)and instrumental seismic intensity were generated,and the spatial distribution characteristics and formation mechanisms of the strong ground motion field were quantitatively discussed.The results indicate that:(1)Under a 5%damping ratio,the simulated PSA values match the observations well in both amplitude and spectral shape within the period range of 0.04-4.00 s.The residuals mainly fall within the range of±1.0 without significant period dependence,verifying the reliability of the model in the complex crustal environment of the southern Qing-hai-Xizang Plateau.(2)The simulated ground motion intensity isovalues exhibit a nearly north-south elliptical dis-tribution.The peak PGA near the epicenter reaches 1 184.3 cm/s2,with a calculated instrumental seismic intensity of 9.6.While covering the actual seismic damage risk,the simulation results show good consistency with both macro-seismic investigations and instrumental observations.(3)The ground motion intensity field clearly demon-strates significant rupture directivity and hanging-wall effects.Specifically,the PGA in the forward rupture direc-tion(northward)is approximately 1.82 times that in the backward direction,and the PGA on the hanging wall is amplified by approximately 1.85 times compared to the footwall.These refined spatial distribution characteristics provide a dynamic basis for explaining macro-seismic damage variations and offer important scientific references for the seismic design of rural buildings and emergency response in southern Xizang.关键词
随机有限断层法/定日地震/震源模型/峰值加速度/烈度Key words
stochastic finite-fault method/Dingri earthquake/source model/peak ground acceleration/seis-mic intensity分类
天文与地球科学引用本文复制引用
张严方,孟庆筱,胡郢,游姗,景鹏旭..基于随机有限断层法的2025年西藏定日MW7.1地震强地震动模拟[J].地球与行星物理论评（中英文）,2026,57(6):700-713,14.基金项目
2024年地震行业标准制修订项目计划(2024DBJCYB13) （2024DBJCYB13）
中央级公益性科研院所基本科研业务费专项(DQJB24Z11) Supported by the Project Plan for the Development and Revision of Earthquake Standards(Grant No.2024DBJCYB13)and the Basic Research Fund of Central Public Welfare Research Institutes(Grant No.DQJB24Z11) （DQJB24Z11）
