Green’s functions extraction and surface-wave tomography from microseisms in southern California
Green’s functions extraction and surface-wave tomography from microseisms in southern California
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DOI：
10.1190/1.2210607
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发表时间：
2006-08
期刊：
影响因子：
3.3
通讯作者：
P. Gerstoft;K. Sabra;P. Roux;W. Kuperman;M. Fehler
中科院分区：
文献类型：
--
作者：
P. Gerstoft;K. Sabra;P. Roux;W. Kuperman;M. Fehler
本文利用加州南部151个台站的地震噪声资料进行互相关分析，提取台站间面波群速度，以确定面波速度结构。我们开发了一个自动化的程序，估计的绿色的功能和随后的层析反演从11,325站对的基础上的噪声场的特性。我们消除特定的事件的程序，不引入任何虚假的频谱失真的频带内的利益，0.05-0.2赫兹。此外，我们仅使用高于阈值信噪比的新兴到达结构。其结果是，大多数站对与他们的轴朝向大海被使用，一致的噪音有一个微震起源。最后，实际上与绿色函数相关的是相关函数的时间导数。时域绿色函数的出现与记录时间的平方根成正比，与站间距离的平方根成反比。层析反演产生的面波速度图相比，更传统的和复杂的实验程序。
We use crosscorrelations of seismic noise data from 151 stations in southern California to extract the group velocities of surface waves between the station pairs for the purpose of determining the surface-wave velocity structure. We developed an automated procedure for estimating the Green’s functions and subsequent tomographic inversion from the 11,325 station pairs based on the characteristics of the noise field. We eliminate specific events by a procedure that does not introduce any spurious spectral distortion in the band of interest, 0.05–0.2 Hz. Further, we only used the emerging arrival structure above a threshold signal-to-noise ratio. The result is that mostly station pairs with their axes oriented toward the sea are used, consistent with the noise having a microseism origin. Finally, it is the time derivative of the correlation function that is actually related to the Green’s function. The emergence of the time-domain Green’s function is proportional to the square root of the recording time and inversely proportional to the square root of the distance between stations. The tomographic inversion yields a surface-wave velocity map that compares favorably with more conventional and elaborate experimental procedures.