【摘要】 选取从96个汶川地震余震中由28个强震动台站获取的602组强震动记录,假设地表观测到的地震动由震源、路径和场地三项因素组成,运用广义反演法(GIT)分离这三项因素,获得这些台站的场地反应,并与采用HVSR法获得的结果进行比较。结果表明:两种方法获得的场地卓越频率具有较好的一致性,但是对于1.0～5.0Hz、5.0～10.0Hz和1.0～10.0Hz频段内的平均场地放大,HVSR法获得的结果要普遍小于广义反演法。进一步说明了HVSR方法可以合理精确地估计场地的卓越频率但却低估平均场地放大。最后统计这三个频段内的平均场地放大与台站上覆土层20m的平均剪切波速(V s20)间的函数关系,结果表明两者之间存在较强的相关性。更多还原

【Abstract】 Total 602 recordings from 28 strong motion stations captured in 96 aftershocks of the Wenchuan Earthquake were selected and processed at first.It was assumed that the observed surface ground motion is comprised of three factors that are the source,path and site.The generalized inversion technique(GIT) was applied to separate these factors and then the site responses of these stations were obtained.Comparing them with the ones by the HVSR method,it shows that the site predominant frequency from two methods have a good agreement,but for the average site amplification in the frequency bands of 1.0-5.0Hz,5.0-10.0Hz and 1.0-10.0Hz,the results by HVSR method are mostly smaller than the ones by GIT.It further illustrates that the HVSR method can accurately evaluate the site predominant frequency but underestimate the site amplification amplitude.At last the relationship between the average site amplification of those three frequency bands and the average uppermost-20m shear wave velocity(V s20) was regressed.It shows that there is a strong correlation between them.更多还原