SEISMOLOGY AND GEOLOGY ›› 2025, Vol. 47 ›› Issue (3): 897-916.DOI: 10.3969/j.issn.0253-4967.2025.03.20250038

Previous Articles     Next Articles

RESEARCH ON GROUND MOTION SIMULATION OF THE DINGRI MS6.8 EARTHQUAKE IN XIZANG BASED ON DIFFERENT SOURCE MODELS

YIN Xiao-fei1)(), QIANG Sheng-yin2), ZHANG Wei3),*(), SHAO Zhi-gang1), WANG Wu-xing1), YUAN Xiao-xiang1), LI Yong-sheng4), LIU Hao5)   

  1. 1)Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China
    2)Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, China
    3)Department of Earth and Space Science, Southern University of Science and Technology, Shenzhen 518055, China
    4)National Institute of Natural Disaster Prevention and Mitigation, Ministry of Emergency Management, Beijing 100085, China
    5)Shanghai Research Institute of Building Sciences Company Limited, Shanghai 200032, China
  • Received:2025-01-26 Revised:2025-02-11 Online:2025-06-20 Published:2025-08-13

基于不同震源模型的西藏定日 MS6.8 地震强地面运动模拟研究

尹晓菲1)(), 强生银2), 张伟3),*(), 邵志刚1), 王武星1), 袁小祥1), 李永生4), 刘浩5)   

  1. 1)中国地震局地震预测研究所, 北京 100036
    2)中国地震局工程力学研究所, 哈尔滨 150080
    3)南方科技大学地球与空间科学系, 深圳 518055
    4)应急管理部国家自然灾害防治研究院, 北京 100085
    5)上海市建筑科学研究院有限公司, 上海 200032
  • 通讯作者: *张伟, 男, 1976年生, 教授, 主要从事复杂介质地震波数值模拟算法和高性能计算、 内部结构成像、 地震和微地震监测等方面的研究, E-mail:
  • 作者简介:

    尹晓菲, 女, 1989年生, 副研究员, 主要研究方向为强地面运动模拟、 高频面波方法、 地震活动等方面的研究, E-mail:

  • 基金资助:
    国家重点研发计划项目(2023YFC3007304); 中国地震局地震预测研究所基本科研业务专项(CEAIEF2024030205)

Abstract:

On January 7, 2025, a magnitude MS6.8 earthquake occurred in Dingri County, Shigatse City, within the Xizang(Tibet)Autonomous Region. This normal-faulting earthquake struck the Lhasa Terrane in the southern Tibetan plateau, a region characterized by a series of nearly north-south trending normal faults and associated tectonic rift valleys—features indicative of the region’s ongoing extensional deformation and potential for future strong seismic events. Given the high seismic hazard in the southern Qinghai-Xizang Plateau and the area’s complex mountainous terrain, which increases the likelihood of secondary disasters such as landslides, assessing strong ground motion is crucial for linking and quantifying seismic hazard and risk. Accordingly, simulating strong ground motion for a hypothetical MS6.8 earthquake in this region holds significant practical value. Such analysis contributes both theoretical insight and practical guidance for regional seismic disaster prevention and mitigation.

This study simulates the strong ground motion of the Dingri MS6.8 earthquake using two source models derived from joint inversion of InSAR coseismic deformation, teleseismic waveforms, and strong motion recordings. A three-dimensional curvilinear finite-difference method with curved grid meshing is employed to model the seismic wave propagation and ground motion characteristics. By comparing the results of the two source models, the spatial distribution of seismic ground motion and the underlying causative mechanisms are analyzed. The key findings are as follows:

(1)Simulated ground velocity time histories at four near-field stations, processed with a 0.2Hz low-pass Butterworth non-causal filter, closely match the observed strong motion records, verifying the accuracy and reliability of the simulations.

(2)Due to a NNE-directed unilateral rupture, peak ground velocities(PGVs)in the forward rupture direction(NNE)are significantly higher than those in the reverse direction(SSW), demonstrating a clear rupture directivity effect.

(3)A comparison of PGV distributions across the fault shows that values on the upper plate(western side)are significantly higher than those on the lower plate(eastern side), indicating a strong upper-plate effect. Vertical surface displacements on the fault’s upper plate, as simulated by the two models, reach 2.0m and 2.1m, respectively—values that are in close agreement with field measurements from the Dingri earthquake geological survey.

(4)Both source models simulate a maximum seismic intensity of Ⅸ, with high-intensity zones extending predominantly in the NNE direction. The simulated intensity distributions are generally consistent with field observations, though discrepancies exist in two areas: From northern Dingri County to southwestern Angren County, and in central-southern Gangba County. The intensity distribution produced by source Model 2 shows better agreement with the observed data.

This study highlights the importance of using source models derived from the joint inversion of InSAR, teleseismic, and strong motion data—or a broader combination of geophysical constraints including GPS—to improve the accuracy of strong ground motion simulations. The results offer an important scientific basis for advancing our understanding of seismic wave propagation and strong ground motion characteristics associated with normal faulting earthquakes in the southern Qinghai-Xizang Plateau.

Key words: Dingri MS6.8 earthquake, strong ground-motion simulation, curvilinear grid finite-difference, source model

摘要:

2025年1月7日西藏自治区日喀则市定日县发生 MS6.8 地震, 此次地震是发生在青藏高原南部拉萨地块内部的正断型地震, 该区域发育一系列近SN向的正断裂及其限定的构造裂谷, 未来仍有发生强震的可能。文中基于InSAR同震变形数据、 远震数据联合反演及基于InSAR同震变形数据、 远震数据和强震数据联合反演获得的2种震源模型, 采用三维曲线网格有限差分方法对定日 MS6.8 地震的强地面运动过程进行模拟。研究结果表明: 1)2种震源模型模拟计算的速度时程同强震动观测记录能够较好吻合, 验证了模拟结果的准确性和有效性; 2)受震源NNE向单侧破裂过程的影响, 破裂前方(NNE向)模拟计算的峰值地表速度(PGV)明显高于破裂后方(SSW向), 体现了此次地震的破裂方向性效应; 3)断层与地表交线两侧的PGV分布差异揭示了定日 MS6.8 地震存在显著的断层上盘效应, 2种震源模型模拟计算的断层上盘地表垂向位移分别达2.0m和2.1m, 与定日地震科考团队野外地质调查的同震垂直位错基本一致; 4)利用2种震源模型模拟计算的本次地震的最大烈度均为Ⅸ度, 高烈度区主要沿NNE向展布, 理论烈度与野外调查的地震烈度分布基本符合, 然而二者在定日县以北到昂仁县西南、 岗巴县中南部的2个区域范围存在差异, 模型2的烈度分布与野外调查的烈度较为接近。建议在进行强地面运动模拟时, 应选择联合多种数据(如远震、 强震、 InSAR、 GPS等)反演获得的震源模型, 这将有利于获得更精确的地震动结果。

关键词: 定日MS6.8地震, 强地面运动模拟, 曲线网格有限差分, 震源模型