S-wave attenuation of the shallow sediments in the North China basin based on borehole seismograms of local earthquakes
S-wave attenuation of the shallow sediments in the North China basin based on borehole seismograms of local earthquakes
复制标题
基于当地地震钻孔地震图的华北盆地浅层沉积物横波衰减
DOI：
10.1093/gji/ggy223
复制
发表时间：
2018-06
影响因子：
2.8
通讯作者：
Li Zhiwei
中科院分区：
文献类型：
--
作者：
Wang Sheng;Li Zhiwei
浅层沉积物的横波速度和衰减结构对强地面运动的准确预报具有重要作用。然而，研究衰减比研究速度结构更困难。在这项研究中，我们开发了一种新的方法来估计频率相关的S波衰减（）结构的浅层沉积物的基础上多时间窗分析的钻孔地震记录从本地地震。用全局最优化方法选择多个时窗，分离钻孔台站近震波形中的直达和地表反射S波。对于不同的时间窗，用加权平均法求出了直达波和地面反射S波之间的传递函数，并在此基础上求出了与频率有关的值。综合试验表明，该方法能恢复出鲁棒可靠的数值，特别是在当地地震数据不丰富的情况下。我们用这种方法对华北盆地14个钻孔地震台的近震波形进行了分析，得到了2-10 Hz频段的值，以及深达几百米的浅层沉积物的平均值和比值。结果表明，该值在0.01-0.06之间，一般随频率的增加而减小.华北盆地14个钻孔站以下几百米深度范围内的浅层沉积物的平均衰减结构可模拟为：与其他地区沉积盆地的衰减结构，如美国密西西比湾沉积和日本仙台盆地的衰减结构大体一致。
S-wave velocity and attenuation structures of shallow sediments play important roles in accurate prediction of strong ground motion. However, it is more difficult to investigate the attenuation than velocity structures. In this study, we developed a new approach for estimating frequency-dependentS-wave attenuation () structures of shallow sediments based on multiple time window analysis of borehole seismograms from local earthquakes. Multiple time windows for separating direct and surface-reflectedS-waves in local earthquake waveforms at borehole stations are selected with a global optimization scheme. With respect to different time windows, the transfer functions between direct and surface-reflectedS-waves are achieved with a weighted averaging scheme, based on which frequency dependentvalues are obtained. Synthetic tests suggest that the proposed method can restore robust and reliablevalues, especially when the data set of local earthquakes is not abundant. We utilize this method for local earthquake waveforms at 14 borehole seismic stations in the North China basin, and obtainvalues in 2–10 Hz frequency band, as well as average,andratio for shallow sediments deep to a few hundred metres. Results suggest thatvalues are to 0.01–0.06, and generally decrease with frequency. The average attenuation structure of shallow sediments within the depth of a few hundred metres beneath 14 borehole stations in the North China basin can be modelled as. It is generally consistent with the attenuation structure of sedimentary basins in other areas, such as Mississippi Embayment sediments in the United States and Sendai basin in Japan.
登录
查看更多内容
影响因子：
2.9
作者：
K. Aki
通讯作者：
K. Aki
DOI：
10.1002/2015jb012210
发表时间：
2015-08
期刊：
Journal of Geophysical Research: Solid Earth
影响因子：
--
作者：
M. Gal;A. Reading;S. Ellingsen;L. Gualtieri;K. Koper;R. Burlacu;H. Tkalčić;M. Hemer
通讯作者：
M. Gal;A. Reading;S. Ellingsen;L. Gualtieri;K. Koper;R. Burlacu;H. Tkalčić;M. Hemer
渤海盆地第四纪沉积物近地表速度及QS结构
DOI：
10.1007/s11589-009-0451-1
发表时间：
2009-10
期刊：
Earthquake Science (地震学报英文版)
影响因子：
--
作者：
倪四道
通讯作者：
倪四道
影响因子：
3.3
作者：
S. Ni;Zhiwei Li;P. Somerville
通讯作者：
S. Ni;Zhiwei Li;P. Somerville
影响因子：
3
作者：
D. Jongmans;P. Malin
通讯作者：
D. Jongmans;P. Malin