起伏地表条件下2.5维声波方程有限差分法数值模拟

针对三维数值模拟难以应对的大尺度模拟或快速计算问题，2.5维数值模拟是一种能兼顾模拟精度和计算效率的有效折中手段。基于L型2.5维声波近似方程，通过纵向坐标变换，采用有限差分法实现了起伏地表条件下2.5维声波方程数值模拟。理论模型试算结果表明，2.5维声波方程有限差分数值模拟方法能够很好地处理起伏地表问题；与起伏地表二维声波方程数值模拟结果相比，两者在地震波运动学特征上基本一致，而在地震波动力学特征模拟上2.5维数值模拟更具优势；通过不同炮检距模拟记录的振幅对比，验证了2.5维声波方程数值模拟在时间和空间上的衰减特性。

Aimed at the problems of large scale simulation and rapid calculation,as an effective and comprise means,2.5D numerical simulation balances simulation accuracy and calculation efficiency,instead of 3D numerical simulation.Based on L pattern 2.5D acoustic wave equation,a 2.5D acoustic wave equation numerical simulation from rugged topography with finite differential strategy is realized by the longitudinal coordinate transformation.The theoretical modeling results show that 2.5D acoustic wave equation numerical simulation can handle the rugged topography problem very well.Compared with the 2D acoustic wave equation numerical simulation results,they are consistent in kinematics characteristics of seismic wave while in dynamic characteristics of seismic wave the results of 2.5D coustic wave equation numerical simulation is superior.By the amplitude comparison of simulated recording for different offsets,the attenuation characteristics of 2.5D acoustic wave equation numerical simulation in time and space is verified.