Assessing the reliability of the modified three-component spatial autocorrelation technique
Assessing the reliability of the modified three-component spatial autocorrelation technique
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DOI：
10.1111/j.1365-246x.2006.03253.x
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发表时间：
2007-02
影响因子：
2.8
通讯作者：
A. Köhler;M. Ohrnberger;F. Scherbaum;M. Wathelet;C. Cornou
中科院分区：
文献类型：
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作者：
A. Köhler;M. Ohrnberger;F. Scherbaum;M. Wathelet;C. Cornou
地震环境振动的分析正在成为一种普遍的方法来估计地下剪切波速度剖面。然而，对垂直分量波场数据的共同限制不允许调查Love波频散以及瑞利波和Love波之间的划分。在这项研究中，我们扩展了改进的空间自相关技术（MSPAC）的三分量分析（3C-MSPAC）。通过确定Love波频散曲线，该技术为确定剪切波速度-深度剖面提供了额外的信息。此外，瑞利波在水平分量上的表面波的总部分的相对分数估计。使用合成的环境振动波形数据的3c-MSPAC方法的测试。模拟了不同类型的表面波以及不同的模式。此外，使用不同的空间分布的源。我们得到的瑞利波和爱波频散曲线宽频带的波形模拟所使用的模型一致。这同样适用于瑞利波的相对分数。频散曲线在较低的频率比瑞利波洛夫波。虽然3c-MSPAC具有明显的优势，确定乐甫波速度，3c-MSPAC和传统的垂直频率波数分析相互补充，在估计瑞利波频散特性。反演的频散曲线的剪切波速度-深度剖面表明，使用洛夫波速度证实了来自瑞利波速度的结果。在存在高阶表面波时，Love波甚至可以改善结果。应用3c-MSPAC的环境振动数据记录在现场测量（普尔海姆，德国）显示乐甫波在波场中占主导地位。该场地现有的剪切波剖面与瑞利波和勒夫波频散曲线反演得到的模型一致。
SUMMARY Analysis of seismic ambient vibrations is becoming a widespread approach to estimate subsurface shear wave velocity profiles. However, the common restriction to vertical component wavefield data does not allow investigations of Love wave dispersion and the partitioning between Rayleigh and Love waves. In this study we extend the modified spatial autocorrelation technique (MSPAC) to three-component analysis (3c-MSPAC). By determination of Love wave dispersion curves, this technique provides additional information for the determination of shear wave velocity–depth profiles. Furthermore, the relative fraction of Rayleigh waves in the total portion of surface waves on the horizontal components is estimated. Tests of the 3c-MSPAC method are presented using synthetic ambient vibration waveform data. Different types of surface waves are simulated as well as different modes. In addition, different spatial distributions of sources are used. We obtain Rayleigh and Love wave dispersion curves for broad frequency bands in agreement with the models used for waveform simulation. The same applies for the relative fraction of Rayleigh waves. Dispersion curves are observed at lower frequencies for Love waves than for Rayleigh waves. While 3c-MSPAC has clear advantages for determination of Love waves velocities, 3c-MSPAC and conventional vertical frequency–wavenumber analysis complement each other in estimating the Rayleigh wave dispersion characteristics. Inversions of the dispersion curves for the shear wave velocity–depth profile show that the use of Love wave velocities confirms the results derived from Rayleigh wave velocities. In the presence of higher mode surface waves, Love waves even can improve results. Application of 3c-MSPAC to ambient vibration data recorded during field measurements (Pulheim, Germany) show dominance of Love waves in the wavefield. Existing shear wave profiles for this site are consistent with models obtained from inversion of Rayleigh and Love wave dispersion curves.