基于连续小波变换的斜坡动力响应特征分析——以四川长宁M_(s)6.0级地震为例  

Time-Frequency characteristics and seismic response analyses of the 6.0-magnitude earthquake,Changning County of Yibin in Southwest China’s Sichuan Province

作　　者：金刚 王运生[1] 何先龙[2] 史丙新[3] 周宇航 JIN Gang;WANG Yunsheng;HE Xianlong;SHI Bingxin;ZHOU Yuhang(State Key Laboratory of Geo-Hazard Prevention and Geo-Environment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Institute of Engineering Mechanics,China Earthquake Administration,Langfang,Hebei 065000,China;Seismological Bureau of Sichuan Province,Chengdu,Sichuan 610041,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [2]中国地震局工程力学研究所,河北廊坊065000 [3]四川省地震局,四川成都610041

出　　处：《中国地质灾害与防治学报》2021年第2期1-8,共8页The Chinese Journal of Geological Hazard and Control

基　　金：国家创新研究群体科学基金(41521002);国家自然科学基金(41877235)。

摘　　要：川西北地区深切峡谷发育,地震扰动频繁。峡谷内高陡岩质斜坡在强震扰动下,通常会发生震裂松弛,进而导致失稳,因此研究其强震响应意义重大。2019年四川长宁M_(s)6.0级地震触发了布置在石棉县城南桠河两岸的3台强震监测仪器,通过对捕捉到的强震数据进行连续小波变换之后,获取了其时频信息。分析结果表明:(1)S波在频域上分为两种成分,其主频值分别为3.5 Hz和1.1 Hz附近;(2)山脊处的地震动放大效应主要体现为S波相对高频成分上能量的增加而低频部分则无显著变化;(3)覆盖层场地自振频率与S波低频成分主频相近,二者产生共振,导致S波低频放大与高频衰减效应;(4)地震动响应具有极强的方向性,水平向地震动放大效应比垂直向更为显著。In northwest Sichuan Province,due to the frequent earthquakes,the rocky hill slopes in the valley area usually get loosen and lead to the failure.For geohazard prevention and mitigation,it is important to determine the site amplification effects and seismic responses of hillslopes.For example,the 2019 Changning M_(s)6.0 earthquake that occurred in Changing County of Yibin,Sichuan Province,China,was well recorded in three earthquake monitoring stations located on both bank sides of Nanya River in Shimian County,Sichuan Province,China.In this study,detailed analyses of the recorded seismic data had been conducted with the method of Continuous Wavelet Transform and confirmed the following observations:(1)For S-wave,two sorts of components in the frequency domain were found,whose main frequency values were around 3.5 Hz and 1.1 Hz respectively.(2)The seismic amplification effect at the ridge was mainly reflected by the energy increase in the high frequency component of the S-wave,no clear changes in the low frequency component of the S-wave was found.(3)In soil site,the natural frequency of vibration was close to the main frequency of the low frequency component of the S-wave,resonance between the two components was generated,resulting in low-frequency amplification and high-frequency attenuation effect.(4)The seismic response to mountain hill slopes had a strong directivity,and the amplification effect in the horizontal directions was much stronger than that of the vertical directions.

关 键 词：连续小波变换 长宁地震 山体地震动响应 时频分析 

分 类 号：P694[天文地球—地质学]