基于机器学习的区域地震动模拟——以2022年泸定MS6.8地震为例  

Machine learning-based regional ground seismic motion simulation:A case study of the MS6.8 Luding earthquake in 2022

作　　者：陈凯 潘华[1] Chen Kai;Pan Hua(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Chongqing Earthquake Agency,Chongqing 401147,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]重庆市地震局,重庆401147

出　　处：《地震学报》2025年第2期242-253,共12页Acta Seismologica Sinica

基　　金：国家重点研发计划课题项目(2022YFC3003502)资助。

摘　　要：利用机器学习中的主成分分析法(PCA)提取了2022年泸定M_(S)6.8地震的M5.0余震(2022年10月22日)的特征主成分时程,对泸定M_(S)6.8主震的地震动时程进行模拟。在此过程中,将主震目标台站的地震动峰值加速度和反应谱作为约束条件,利用粒子群优化(PSO)算法计算特征主成分时程的组合系数。结果显示模拟结果与真实记录较为一致。这表明:利用机器学习算法能够通过提取余震的特征主成分时程对目标地震进行模拟;在进行小区域地震动模拟时,通过选取具有一致地形效应的地震动数据可以避免特殊地形效应所导致的该主成分缺失。The seismic time history plays a crucial role in pre-earthquake risk assessment and post-earthquake damage evaluation.However,due to the uncertainty in simulated ground seismic motion parameters,there are notable differences between simulation results and actual records.Fortunately,advancements in data mining techniques and the availability of high-quality strong ground seismic motion observation records have made it possible to simulate earthquakes by extracting seismic characteristic records.On September 5,2022,an M_(S)6.8 earthquake struck Luding County,Garze Tibetan Autonomous Prefecture,Sichuan Province,China,with epicenter location(29.59°N,102.08°E),and a focal depth of 16 km.This event occurred in the southeastern segment of the Xianshuihe fault zone,near the Moxi fault and Jinpingshan fault.According to the intensity survey results released by the China Earthquake Administration,the major axis of the isoseismal lines of the Luding earthquake trended northwest,with dimensions of 195 km by 112 km,and the intensity in the most affected area reached levelⅨ.The area with intensityⅥor above covered 19089 square kilometers.The earthquake caused significant damage to infrastructure,including roads,bridges,buildings,and lifeline projects,resulting in casualties and triggering secondary hazards such as landslides.Following the Luding M_(S)6.8 main shock,several aftershocks occurred,the most notable of which was the M_(S)5.0 event on October 22,2022.This study selected seismic records from the M_(S)5.0 earthquake on October 22,2022.According to the Global Centroid Moment Tensor(GCMT)results,the focal mechanism of the M_(S)6.8 main shock indicates a strike of 164°,dip of 78°,and slip of 7°,and the M_(S)5.0 aftershock focal mechanism shows a strike of 167°,dip of 48°,and slip of−53°.The main shock is characterized as a strike-slip earthquake,while the aftershock involves both thrust and strikeslip components.Fifteen stations with three-component records from the aftershocks were selected for feature prin

关 键 词：机器学习 地震动模拟 主成分分析 粒子群算法 

分 类 号：P315.9[天文地球—地震学]