Rapid Simulation of Acceleration Waveform at Everest Seismic Station of Xizang Tingri MS6.8 Earthquake on January 7, 2025
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摘要: 2025年1月7日，西藏日喀则市定日县发生MS6.8地震，震中附近遭受了严重的地震破坏. 地震影响区位于海拔4 000 m以上的高原地带，地震台站分布稀少，100 km内缺乏完整的基准台或基本台地震记录，而这些记录对于快速评估地震灾害程度和指导震后重建有至关重要的意义. 本次地震影响区域内的高山多覆盖有永久冰川（如珠峰地区），同时存在大量潜在的滑坡体，研究地震对冰川及滑坡体稳定性的影响，是值得关注的重要科学问题. 基于上述背景和研究需求，选择距离震中55公里的珠峰地震台记录到的一次MS3.9小震作为格林函数采用经验格林函数方法，考虑参数不确定性，合成了本次地震在珠峰地震台的加速度波形. 研究结果表明：珠峰地震台在本次地震中水平向PGA范围为70~190 cm/s2，垂直向PGA范围为40~140 cm/s2，对应的仪器地震烈度为Ⅵ~Ⅶ度. 这些结果反映了珠峰地震台位置的地震动强度，与第五代中国地震动参数区划图中不同概率水准的地震动反应谱进行对比，并结合当地房屋建筑的结构性能，分析认为该强度地震动可能对珠峰地震台附近的一般民用建筑造成较严重损伤，震中附近的地震破坏可能会更为严重. 同时该地震可能对高海拔冰川和潜在滑坡体稳定性造成影响，建议对此问题给予特别关注.Abstract: On January 7, 2025, a magnitude MS6.8 earthquake occurred in Dingri County, Shigatse City, Xizang, China, causing severe damage near the epicenter. The affected area is located on a plateau at over 4, 000 meters above sea level, where seismic stations are sparsely distributed. There is a lack of comprehensive reference data or basic seismic records within a 100 km radius, which are essential for quickly assessing the extent of earthquake damage and guiding post-earthquake reconstruction efforts. The high mountain region affected by this earthquake is mostly covered with permanent glaciers, such as those on Mount Everest, and contains numerous potential landslide sites. Studying the impact of earthquakes on the stability of glaciers and landslides is an important scientific concern. Given this context, this article focuses on an MS3.9 small earthquake recorded at the XZ-ZHF seismic station, located 55 km from the epicenter. Using the empirical Green's function method, the study considers parameter uncertainty to synthesize the acceleration waveform of the earthquake at this station. The research results indicate that the horizontal peak ground acceleration (PGA) at Zhufeng seismic station ranged from 70 to 190 cm/s2, while the vertical PGA ranged from 40 to 140 cm/s2. This corresponds to an instrument seismic intensity of Ⅵ-Ⅶ. These findings reflect the seismic intensity at the Zhufeng Seismic Station. When compared with the seismic response spectra of various probability levels in the fifth-generation Seismic ground motion parameters zonation map of China, and taking into account the structural integrity of local buildings, it is analyzed that the seismic intensity could cause more severe damage to general civil structures near the Zhufeng seismic station. Furthermore, it is expected that the earthquake damage near the epicenter is likely to be even more severe. Additionally, the earthquake may have implications for the stability of high-altitude glaciers and potential landslide bodies, and it is recommended that special attention be paid to these issues.
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图 1 定日地震震中位置、宏观地震烈度、历史地震和余震目录
历史地震和余震目录来源于中国地震台网，最后一次访问时间为2025年1月16日14时. 宏观地震烈度来源于
http://www.mem.gov.cn Fig. 1. The epicenter location of the Dingri earthquake, the macroseismic intensity distribution, historical earthquakes, and aftershock catalogue
图 2 小震合成大震示意图及本次合成珠峰地震台主震波形所用的格林函数
Fig. 2. The concept of synthesizing smaller earthquakes to simulate a larger earthquake, along with the Green's functions for the mainshock of XZ-ZFZ used in this synthesis.
图 3 定日地震强震破裂模型
a.张勇团队破裂模型；b.USGS破裂模型
Fig. 3. The rupture models for the Dingri earthquake
图 4 珠峰地震台的模拟地震动
A. 黑色曲线表示EW分量，蓝色曲线表示NS分量，红色曲线表示UD分量；B. 珠峰地震台的模拟地震动的加速度反应谱；a. 黑色曲线表示EW分量；b. 红色曲线表示NS分量；c. 蓝色曲线表示UD分量
Fig. 4. The synthesizing ground motion at the XZ-ZHF
图 5 珠峰地震台的模拟基岩层面的地震动的加速度反应谱与Ⅱ类场地设计谱
Fig. 5. Acceleration response spectrum of simulated bedrock surface seismic motion and Class Ⅱ site design spectrum of XZ-ZHF
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