Research on the middle-of-receiver-spread assumption of the MASW method
Research on the middle-of-receiver-spread assumption of the MASW method
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DOI：
10.1016/j.soildyn.2008.01.009
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发表时间：
2009
影响因子：
4
通讯作者：
Yinhe Luo;J. Xia;Jiangping Liu;Yixian Xu;Qingsheng Liu
中科院分区：
文献类型：
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作者：
Yinhe Luo;J. Xia;Jiangping Liu;Yixian Xu;Qingsheng Liu
多道面波分析方法是确定近地表横波速度的有效方法。从瑞利波测量值估计横波速度剖面是简单的。横波速度剖面的获取需要三个步骤：利用滚动模式沿着线性测线采集多个多道记录，提取瑞利波频散曲线，反演每个炮集的横波速度剖面频散曲线。通过对一维横波速度模型进行对齐，可以生成伪二维横波速度剖面。在这个过程中，理解反演的1D S波速度剖面应该位于何处是非常重要的：每个排列的中点（接收器排列的中间假设）或震源和最后一个接收器之间的某处。换句话说，所提取的频散曲线由地震检波器排列内的地球物理结构确定或者受源地球物理结构的强烈影响。本文通过固定接收机展布和改变源位置，计算了合成数据集和一个实际例子的频散曲线。结果表明，频散曲线主要由接收器排列内的结构决定。
The multichannel analysis of surface wave (MASW) method has been effectively used to determine near-surface shear- (S-) wave velocity. Estimating the S-wave velocity profile from Rayleigh-wave measurements is straightforward. A three-step process is required to obtain S-wave velocity profiles: acquisition of a multiple number of multichannel records along a linear survey line by use of the roll-along mode, extraction of dispersion curves of Rayleigh waves, and inversion of dispersion curves for an S-wave velocity profile for each shot gather. A pseudo-2D S-wave velocity section can be generated by aligning 1D S-wave velocity models. In this process, it is very important to understand where the inverted 1D S-wave velocity profile should be located: the midpoint of each spread (a middle-of-receiver-spread assumption) or somewhere between the source and the last receiver. In other words, the extracted dispersion curve is determined by the geophysical structure within the geophone spread or strongly affected by the source geophysical structure. In this paper, dispersion curves of synthetic datasets and a real-world example are calculated by fixing the receiver spread and changing the source location. Results demonstrate that the dispersion curves are mainly determined by structures within a receiver spread.