泸定地震大渡河区域灾害调查及格林函数库应用可行性探讨

Abstract

2022年9月5日，四川省甘孜州泸定县发生M_S6.8地震，造成了较为严重的人员伤亡. 震后中国地震局地球物理研究所科考队对泸定M_S6.8地震中大渡河干流上的几座梯级水电站和极震区等附近区域进行了灾害调查. 调查结果表明梯级电站在本次地震中受影响较小，不影响正常运转. 地震发生后，我们也采用经验格林函数方法并考虑震源参数的不确定性特征，对震区的石棉擦罗地区（位置①）、大渡河流域兴康高速特大桥区域（位置②）、历史地震古滑坡—摩岗岭附近区域（位置③）等三个典型位置合理范围的地震动加速度时程进行了快速估计. 初步结果表明：位置①和③建筑物存在被本次地震破坏的可能性；位置②桥梁受地震破坏的可能性较小. 最后，结合本次灾害调查结果、工程自建地震监测台网、典型位置地震动快速估计的结果，本文对重点工程区域建设基于实际小震波形的格林函数数据库应用前景的可行性进行了探讨.

Alternate abstract:

On September 5, 2022, an M_S6.8 earthquake occurred in Luding County, Ganzi Prefecture, Sichuan Province, China, causing extensive damage. The scientific expedition team of the Institute of Geophysics of the China Earthquake Administration investigated the damage caused by the earthquake in several terrace hydropower stations on the main stream of the Dadu River and nearby areas. It was determined that the cascade power stations ware less affected by the earthquake and that normal operation was not affected. Using the empirical Green's function method and considering the uncertainty characteristics of the seismic source parameters, the ground motion acceleration time histories were estimated for a reasonable range of three typical locations in the seismic region: the Shimian Caluo area (termed location 1), the Xingkang Expressway bridge area in the Dadu River basin (termed location 2), and the area near the historical seismic ancient landslides (Mogangling, termed location 3). The preliminary results showed that: buildings at locations 1 and 3 may be destroyed by an earthquake of this strength, whereas the bridges in location 2 are less likely to be destroyed. Here, combining the results of the disaster investigation, the seismic network built by the key engineering project, and the results of the rapid estimation of the ground motion at typical locations, we consider the feasibility of applying the Green's function library based on the waveforms of actual small earthquakes in key project areas.