| S波包络时间差影响因素的数值分析di |
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| 引用本文： | 范小平,李清河,杨从杰.S波包络时间差影响因素的数值分析di[J].地震学报,2009,31(4):367-376. |
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| 作者姓名： | 范小平 李清河 杨从杰 |
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| 作者单位： | 1)中国北京100081中国地震局地球物理研究所2)中国南京210014江苏省地震局 |
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| 基金项目： | 科技部攻关项目，地震科学联合基金，中国地震局地球物理研究所论著项目 |
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| 摘 要： | 介质非均匀性可引起高频S波包络的展宽．S波包络展宽是定量研究岩石圈中随机速度非均匀性的有力工具．S波的初至与其均方根包络最大振幅的一半之间的时间延迟定义为S波包络时间差，该时间的大小可反映介质非均匀性强弱．采用有限差分算法模拟了2D von Kaacute;rmaacute;n型随机介质中S波包络的展宽现象，统计分析了影响S波包络时间差的主要因素．结果表明，随机介质中S波传播的距离、随机介质速度扰动率及S波频率均可对S波包络时间差产生影响．相比较而言，速度扰动率对S波包络时间差影响程度最大，S波传播距离次之，S波频率影响程度最小．
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| 关 键 词： | 随机介质 非均匀性 Ｓ波包络展宽 数值分析 |
Numerical simulation on the factors influencing duration time of S wave envelope |
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| Fan Xiao-ping,Li Qing-he,Yang Congjie.Numerical simulation on the factors influencing duration time of S wave envelope[J].Acta Seismologica Sinica,2009,31(4):367-376. |
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| Authors: | Fan Xiao-ping Li Qing-he Yang Congjie |
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| Abstract: | High-frequency S-wave envelope is broadened by medium inhomoge-neity. Analysis of S wave envelope broadening can be a powerful tool for quanti-tative study of random velocity inhomogeneity in the lithosphere. Defining the duration time of S-wave envelope as the time lag from the direct S-wave arrival to the time when the maximum RMS envelope amplitude decays to its half. The length of the S-wave envelope duration may indicate the degree of medium inho-mogeneity. The phenomena of S wave envelope broadening in 2D yon Kármán-type random medium was simulated using finite difference algorithm, and main factors affecting the S-wave envelope duration were statistically analyzed. The result shows that the travel distance of S wave in random medium, the fraction-al velocity fluctuation of the medium and the frequency of S wave can affect the S wave envelope broadening. Relatively, the fractional velocity fluctuation of the random medium affects the envelope broadening mostly, and S wave travel distance in random medium secondly, while the lightest is the S wave frequency. |
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| Keywords: | random medium inhomogeneity of medium S wave envelope broadening numerical simulation |
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