Maslov面波理论地震图
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摘要
研究了横向非均匀介质中的Ｍａｓｌｏｖ面波渐近理论，在横向弱非均匀介质的假设下，介质的纵向非均匀性反应在局部本征函数中，以局部本征函数近似真本征函数是射线理论的直接推论．由此，三维结构下的面波计算退化为准二维问题．由于本文方法属于慢度法，面波的频散使得在一般情况下得不到与体波ＷＫＢＪ方法相似的褶积结果；在震源函数为高斯波包的假设下，得出了与二维体波Ｍａｓｌｏｖ理论图形式上完全相同的褶积结果．还讨论了吸收介质中的面波波包理论图计算，最后结果与二维体波吸收介质中的结果相似．
This paper studied the Maslov's surface asymptotic theory in laterally heterogeneous medium.On the assumption of laterally weak heterogeneous medium the media's vertical heterogineity is reflected by the local eigenfunctions of surface waves.It is the ray theory's direct deduction that using lacal eigenfunction approximates the real eigenfunction of the laterally heterogeneous media.By that,the Surface wave calculation in 3-D medium degenerates in to one in 2-D.Since this method belongs to the slowness method,in general We can't obtain a simple convolution result like the body wave's WKBJ method by the surface wave's dispersion.But ifwe assume the source funtions is Gaussion wavelet,by some approximations we can still obtain a simple convlution result in form like 2-D Maslov's body wave theory. Only obtained the solutions of the standard ray theory we can obtain the uniform asymptotic solutions.
This paper studied the Maslov's surface asymptotic theory in laterally heterogeneous medium.On the assumption of laterally weak heterogeneous medium the media's vertical heterogineity is reflected by the local eigenfunctions of surface waves.It is the ray theory's direct deduction that using lacal eigenfunction approximates the real eigenfunction of the laterally heterogeneous media.By that,the Surface wave calculation in 3-D medium degenerates in to one in 2-D.Since this method belongs to the slowness method,in general We can't obtain a simple convolution result like the body wave's WKBJ method by the surface wave's dispersion.But ifwe assume the source funtions is Gaussion wavelet,by some approximations we can still obtain a simple convlution result in form like 2-D Maslov's body wave theory. Only obtained the solutions of the standard ray theory we can obtain the uniform asymptotic solutions.
引文
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