基于薄层模型的有限频率地震波射线追踪
|
摘要
基于Fermat原理的射线追踪方法都是假定地震波的频率为无限,从而求取最小旅行时所对应的路径。然而实际地震波的频率是有限的,地震波主要是在Fresnel带内沿尽可能短的路径进行传播的。为了使得到的射线路径更符合实际情况,本文在原弯曲射线法的目标函数中加入一项与射线长度有关的惩罚项,实现了基于薄层介质模型的有限频率地震射线近似追踪。理论例子表明,该方法简单,计算速度快,效果良好。
Most ray tracing methods based on Fermat principle assume that the frequency of seismic wave is high enough, hence calculate the corresponding ray paths of minimum traveltime. But in fact, the frequency of seismic wave is finite and most of the energy travels along the shortest path within its Fresnel zone. In order to make the calculated ray paths more according with the real one, we add a penalty term related to the length of the path to the objective function of the former ray bending method, so as to realize ray tracing of finite frequency seismic wave based on the thinly layered models. Theoretical model example shows that, though the algorithm is simple, it produces fast computation speed and good results.
Most ray tracing methods based on Fermat principle assume that the frequency of seismic wave is high enough, hence calculate the corresponding ray paths of minimum traveltime. But in fact, the frequency of seismic wave is finite and most of the energy travels along the shortest path within its Fresnel zone. In order to make the calculated ray paths more according with the real one, we add a penalty term related to the length of the path to the objective function of the former ray bending method, so as to realize ray tracing of finite frequency seismic wave based on the thinly layered models. Theoretical model example shows that, though the algorithm is simple, it produces fast computation speed and good results.
引文
[1]Cerveny V,Soares J E P.Fresnel volum e ray tracing.Geophysics,1992,57(7):902～915
[2]Bube K P,W ashbourne J K.W avetracing:Raytracing for the propagation of band-lim ited signals:part1-theory.SEG71st Ann.Internet.M tg.,Expanded A bstracts,2001
[2]Bube K P,W ashbourne J K.W avetracing:Raytracing for the propagation of band-lim ited signals:part1-theory.SEG71st Ann.Internet.M tg.,Expanded A bstracts,2001
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心