2022年6月1日芦山MS6.1地震近场地震动特征及与西南地区地震动预测方程的对比分析  

Analysis of strong ground motion characteristics in the near-field for the June 1,2022 MS6.1 Lushan earthquake and comparison with the GMPE in southwest China

作　　者：张斌 俞言祥[3] 荣棉水 傅磊[3] 谢俊举[3] 李小军[4] 陈苏 张旭[3] 马秀敏[1,2] ZHANG Bin;YU YanXiang;RONG MianShui;FU Lei;XIE JunJu;LI XiaoJun;CHEN Su;ZHANG Xu;MA XiuMin(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Observation and Research Station of Crustal Stress and Strain in Beijing,Ministry of Natural Resources,Beijing 100081,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部北京地壳应力应变野外科学观测研究站,北京100081 [3]中国地震局地球物理研究所,北京100081 [4]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《地球物理学报》2023年第11期4572-4581,共10页Chinese Journal of Geophysics

基　　金：国家重点研发计划(2022YFC3003503);中国地质调查局项目(DD20190546);国家自然科学基金(51878625)联合资助。

摘　　要：基于芦山MS6.1地震的61组强震动记录,分析近场强震动记录的幅值特征、水平向地震动强度的空间分布;将近场台站加速度反应谱值与NGA-West2和ZYLW22模型的预测中值进行对比;结合实际观测值与ZYLW22模型预测中值的对比、事件内残差的分布,检验此次芦山MS6.1地震是否符合西南构造活跃区主震的地震动衰减特性.研究结果表明,(1)近场台站记录的地震动强度均小于中国地震局划定地震烈度相对应的值;(2)空间分布显示断层破裂前方(震中北东向)的反应谱值大于相同距离处的破裂后方,在长周期表现的更为明显.断层破裂前方的水平向SA在短周期大于NGA-West2和ZYLW22模型的预测中值,而断层破裂后方的水平向SA在整个周期范围内与ZYLW22模型的预测中值相差不大,地震动的方向性效应较为显著;(3)ZYLW22模型可以很好地预测芦山MS6.1地震大多数水平向地震动.构造活跃区和稳定区的地震动衰减速率不同,西南地区应按构造活跃区和稳定区分别进行地震动预测方程研究,并需进一步考虑震源破裂方向性以及盆地效应的影响.Based on 61 three-component strong motion acceleration records of the MS6.1 Lushan earthquake,we analyzed the characteristics of near-field strong ground motion amplitude,and spatial distribution of horizontal ground motion intensity.Then we compared spectral accelerations(SAs)observed in the near-field stations with the median predictions of the NGA-West2 and ZYLW22 ground motion prediction equations(GMPEs).To test whether the MS6.1 Lushan earthquake conforms to the ground motion attenuation characteristics of the main shock in southwest China,we compared the observed values to the median predictions of the ZYLW22 GMPEs,as well as analyzed the distribution of the within-event residuals.The results show that:(1)the ground motion intensity recorded by some near-field stations is much smaller than the corresponding ground motion intensity of the seismic intensity delineated by the China Earthquake Administration.(2)The spatial distribution shows that the SAs observed in the rupture forward(north-east of the epicenter)are larger than those in the rupture backward at the same distance,especially in the long period;The short-period SAs observed in the rupture forward are greater than the median predictions of NGA-West2 and ZYLW22 GMPEs,while the SAs observed in the rupture backward are almost the same as the median predictions of ZYLW22 GMPEs throughout the period,showing a relatively significant directivity effect.(3)The ZYLW22 GMPE can well predict most horizontal ground motion of the MS6.1 Lushan earthquake.The ground motion attenuation rates are different between the active tectonic regime and the stable tectonic regime.The GMPE study in southwest China should be carried out in the tectonic active regime and the stable regime,respectively,and the influence of the directivity effect and basin effect should be considered in the GMPE.

关 键 词：芦山Ms6.1地震 地震动空间分布 方向性效应 地震动预测方程 盆地效应 

分 类 号：P315[天文地球—地震学]