【作者】 唐小平；

【导师】 白超英；

【作者基本信息】 长安大学 ， 地球探测与信息技术， 2010， 硕士

【摘要】 本文内容包括三大部分：(1)地震射线追踪正演方法与技术；(2)地震波场模拟与分离技术；(3)多震相走时联合反演方法与技术。地震射线追踪正演方法与技术中首次提出了分区多步最短路径算法(Multistage MSPM),实现了复杂层状介质中多次(反射、透射、及转换)波的追踪计算；同时与目前国际上流行的有限差分解程函方程算法--分区多步快速行进法(Multistage FMM)进行了对比研究与分析,其结论是无论从计算精度,还是CPU时间,Multistage MSPM算法均优于Multistage FMM算法。为了解决多值射线的追踪问题,提出了最短路径下的极值算法,适应于复杂速度构造(如：透镜体、背斜、向斜、塌陷等)中多值射线的追踪计算；为了解决地震勘探的实际问题,提出了最短路径下的界面元法,可进行多次波的射线追踪,其最大的优势在于计算时间。地震波场模拟与分离技术方面,运用高阶有限差分实现了一阶波动方程波场模拟及分离,交错网格下一阶波动方程伪谱法波场模拟及分离,并运用相同的思路实现了二阶波动方程波场模拟及分离,并取得较为理想的效果。多震相走时联合反演方法与技术方面,成功的将分区多步最短路径射线追踪正演算法与子空间反演法相结合,实现了初至波与反射波的联合反演成像,取得了较好的效果。更多还原

【Abstract】 This research paper includes three parts:(1) seismic ray tracing algorithm; (2) seismic wave field modeling; (3) joint travel time tomography with multiple travel time information.Respect to the seismic ray tracing, we first put forward a multistage modified shortest path ray tracing (referred to multistage MSPM), and develop corresponding algorithm to track multiple (reflected, transmitted, and converted) arrivals in complex layered media. The multistage MSPM algorithm is compared against one popular finite difference Eikonal solver (namely the multistage fast marching method, referred to the multistage FMM), as a result, the multistage MSPM is adventurous over the multistage FMM in terms of solution accuracy and CPU time. In order to trace multi-value seismic ray paths in complex structure, we develop another ray tracing method, called the extremum value algorithm based on the multistage MSPM, which is suitable for the multi-value ray path tracing in the complex velocity structure. In the seismic exploration a fast and accurate ray tracing algorithm is needed so that an interface element method is proposed based on the multistage MSPM algorithm, which has a big advance in CPU time.Respect to the seismic wave field modeling, we use finite difference method to realize first-order wave equation simulation and separation, staggered grid pseudo-spectral method for first-order wave equation simulation and separation. Based on the above principle, we realize the second-order wave equation modeling and its separation by using normal grid pseudo-spectral method. The showing results are favorable and satisfactory in terms of solution accuracy and frequency scatter remove.Respect to joint travel time tomography, we successful combines the multistage MSPM algorithm with the subspace inversion solver to form a method for joint travel time tomography with multiple travel time information. The numerical results show its good performance.更多还原