在2013年4月20日四川芦山Ms7.0级地震序列中我国数字强震动台网获得一批主震、强余震记录,这为研究强震台场地特征提供了基础数据。本文基于参考事件的广义反演方法分析了15个强震台站的场地反应,简要分析了地质条件对场地反应的影响,同时对比给出了基于水平垂直谱比法及一维等效线性化方法确定的场地反应。结果表明,本文选用的参考事件理论震源谱可较好地反映实际震源谱,场地反应结论可靠;与广义反演法相比,水平垂直谱比法较可靠地估计峰值频率但明显低估场地反应幅值,一维等效线性化方法也存在低估场地反应的现象;等效剪切波速VS30与场地反应相关性较弱。
A large number of strong motion recordings were obtained in Lushan Earthquake sequence in April 20, 2013 by the National Strong Motion Observation Network System, and those data provided the possibility of inversing the site response. Based on the generalized inversion technology ( GIT), we estimated the site responses of 15 strong motion stations. Meanwhile, the results of horizontal-to-vertical spectra ratio method (HVSR) and one-dimensional equivalent linear method (l-D) were also applied for estimating the site response. The results show the theoretical source spectrum of the reference event could represent the real source spectrum. Compared with the site response estimated by the GIT, the HVSR could estimate the peak frequency well but underestimate the peak am- plitude, and 1-D method also supports similarly results. Equivalent shear wave velocity of 30-meter-thick deposite (Vs30) has poor correlation with site response.