Filtering Surface Waves
Filtering Surface Waves
复制标题
过滤表面波
DOI：
10.3997/2214-4609-pdb.191.12sei9
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Julian Ivanov
中科院分区：
文献类型：
--
作者：
Choon B. Park;Richard D. Miller;Julian Ivanov
随着面波在近地表地震研究中的应用越来越普遍，在不同模式的水平上对面波进行滤波的必要性经常出现。这是因为面波的应用通常只基于基模的分析，而实地调查中所经历的面波通常是多模的，在高频下以更高的模为主。这种支配不可避免地限制了基模在相应频带的可分析带宽。此外，高阶模式的相速度范围往往与基模的相速度范围重叠，这使得传统的饼状切片f-k滤波不能仅用于高阶模式的滤波。介绍了两种方法。在频率-波数(f-k)空间中，通过将拒绝区重新定义为窄而弯曲的(弓形切片)而不是熟悉的饼状区来实现。另一种是利用前面分析的高阶模式的色散信息进行的变频线性移出(FV-LMO)校正来完成必要的滤波。这两种方法在反射处理期间也很有用。
As surface waves become more commonly utilized in near-surface seismic investigations, the necessity of filtering them in the level of different modes often arises. This is because the surface wave application is usually based on the analysis of the fundamental mode only, whereas the surface waves as experienced during field surveys often are mutimodal in nature with higher modes dominating at high frequencies. This domination inevitably limits the analyzable bandwidth of the fundamental mode at the corresponding frequency band. In addition, the phase velocity range of higher modes often overlaps with that of the fundamental mode, making the conventional pie-slice f-k filtering ineffective for the purpose of filtering higher modes only. Two approaches are introduced. One implements in the frequency-wave number (f-k) space by redefining the rejection zone as narrow and curved (bow-slice) instead of the familiar pie-shaped zone. The other accomplishes the necessary filtering by utilizing the frequency-variant linear move out (FV-LMO) correction made from the dispersion information of the higher mode previously analyzed. These two approaches can also be useful during reflection processing.