2021年5月21日漾濞M_(S)6.4地震极震区地形效应对地震动特性的影响  

Impact of topographic effect on ground motion characteristics in the extreme seismic region of Yangbi M_S6.4 earthquake on May 21,2021

作　　者：张立宝 傅磊[1] 周正华 林国良[3] 陈苏[4] 刘爱文[1] 李小军[1,4] Zhang Libao;Fu Lei;Zhou Zhenghua;Lin Guoliang;Chen Su;Liu Aiwen;Li Xiaojun(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;College of Transportation Science&Engineering,Nanjing Tech University,Nanjing 211816,China;Yunnan Earthquake Agency,Kunming 650216,China;Faculty of Urban Construction,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]南京工业大学交通运输工程学院,南京211816 [3]云南省地震局,昆明650216 [4]北京工业大学城市建设学部,北京100124

出　　处：《地震学报》2024年第1期144-156,共13页Acta Seismologica Sinica

基　　金：中国地震局地球物理研究所基本科研业务费(DQJB22X09)资助。

摘　　要：基于对2021年5月21日漾濞M_(S)6.4地震微观震中秀岭村进行的震害调查,利用流动观测地形台阵观测资料,分析了地形效应对地震动特性的影响。结果表明,若地震波垂直山脉走向入射,陡坡会放大地震波的高频部分,且不同高程处,山脉垂向低频差异较大,山脉走向低频差异较小。利用谱衰减法计算高频衰减参数的场地影响项κ_(0),分析了水平和竖向分量的κ_(0)与场地软弱程度和卓越频率的相关性,其结果表明,在小尺度范围内,水平分量和竖向分量的κ_(0)均具有较强的空间不均匀性。Historical earthquake experience has shown that complex terrain in mountainous areas can exacerbate earthquake damage.Complex terrain can alter the duration,amplitude and frequency characteristics of seismic waves,causing unanticipated and severe damage to buildings located on them.On May 21,2021,a M_S6.4 earthquake occurred in Yangbi,Yunnan Province.Near the epicenter of the earthquake,Xiuling village is located in a mountain range with a straight line distance of about 4.5 km from the top to the foot of the mountain,with an elevation difference of about 800 m.The investigation found that the damage to the houses on the top of the mountain was serious,generally manifested as wall collapse or serious damage;the damage to the houses on the mountainside was moderate,manifested as wall collapse and foundation settlement;the damage to the houses at the foot of the mountain was relatively light,without wall collapse,and was dominated by the tensile cracks in the contact surfaces of the structural columns and load-bearing walls.According to the difference in topographic seismic damage,four strong motion observation stations were set up at the top of the mountain,the mountainside and the foot of the mountain in Xiuling village,respectively,on June 8,and a reference station was set up in Huai'an village,which is located in a basin,with a total of five stations,and a total of 63 aftershocks with magnitudes ranging from 1.0 to 4.9 were recorded by the topographic mobile observation station array.According to the spatial distribution of mobile stations and aftershocks,the size of aftershocks and the mountain range orientation,three earthquakes with different magnitudes were selected for acceleration recording analysis,and the analysis results show that when the seismic waves are incident perpendicular to the mountain range orientation,there is anomalous amplification of the high frequency at the steep slopes of the mountainside,and the low-frequency portion of the Fourier amplitude spectrum at different elevations differs s

关 键 词：震害现象 高频衰减参数 场地效应 地形效应 

分 类 号：P315.2[天文地球—地震学]