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用广义反演方法估算了阿拉斯加州中南部安克雷奇盆地场地响应(SR)的空间变化。所分析资料表现的是近震S波水平分量记录的弱运动。数据资料是来自22个便携式临时台站(采用IRIS-PASSCAL仪器)大约6个月时间运行的记录。选定相对每个地震震源到台站的路径效应,然后对数据进行反演确定场地响应值。对所得到的场地响应按2个频段分别求(对数)平均值,一个低频段(LFB),频率从0.5到2.5Hz和一个高频段(HFB),频率从3.0到7.0Hz,低高频段的中心频率分别大约是1.0Hz和5.0Hz。在低频段,场地响应值沿着东部的楚加奇山丘陵从1.0增加到西部的坎贝尔湖和首府山及其周围地区的3.5左右。场地响应值大于3.0的区域与1964年威廉王子海峡地震(Mw=9.2)中广阔的破坏区相关联。在高频段,安克雷奇南边有两个场地响应值大于3.0的小区域连接着特纳甘湾。把用广义反演方法获得的场地响应值与其他研究方法获得的结果进行了对比。结果表明,广义反演法的场地响应值与标准谱比率法(SSR)获得的值大致相当(1∶1),水平与垂直向谱比率法(HVR)获得的场地响应值是广义反演法获得的场地响应值的2倍。研究还发现,在低频段,D级土壤地区的场地响应值SR>2.0,而C级土壤地区的场地响应值SR≤2.0,但在高频段,没有得到土壤类别与场地响应值的关系。
The generalized inversion method is used to estimate the spatial variation of SR in the Anchorage basin in south-central Alaska. The data analyzed show the weak motion recorded by the horizontal component of the near-Earthquake S wave. Data is recorded from approximately 22 portable temporary stations (using the IRIS-PASSCAL instrument) for approximately 6 months. Select the path effect relative to each station from each seismic source, and then invert the data to determine the site response. The resulting site responses were averaged (logarithmically) for each of the two bands, one LFB, a frequency of 0.5 to 2.5 Hz and one HFB, a frequency of 3.0 to 7.0 Hz, a low frequency band The center frequencies are about 1.0 Hz and 5.0 Hz, respectively. At low frequencies, the site response increases along the eastern Chugach Hills from 1.0 to Campbell Lake in the west and around 3.5 in the capital Hill and surrounding area. The area with a site response greater than 3.0 is associated with the extensive destruction in the 1964 Prince William Strait Earthquake (Mw = 9.2). At high frequency, south of Anchorage there are two venues with response values greater than 3.0 connected to a small area of Turner Bay. The response of the site obtained by the generalized inversion method is compared with that obtained by other research methods. The results show that the response of the generalized inversion method is approximately equal to the value obtained by the standard spectral ratio method (SSR) (1: 1), and the response value obtained by the horizontal and vertical spectral ratio method (HVR) is the generalized inversion method 2 times the venue response value obtained. The study also found that in the low frequency range, the site response value of D soil area is more than 2.0, while that of C soil area is less than or equal to 2.0. However, at high frequency, the relationship between soil type and site response is not obtained.