Ultra efficient methods for modelling waveforms in seismic surveys

在这项研究中，我们开发了一种有效的数值方法来模拟地震勘探中的地震波形。在第一年，我们开发了一个非常有效的程序来计算平面波响应的任意一维介质，如梯度速度或随机非均匀结构，在时域有限差分法（FDTD）。这对反射勘探或地震测井数据的分析可能是有用的。在第二年，我们开发了一种超高效的方法，用于模拟折射或广角反射勘探中的地震波形。地震勘探最常见的形式仍然是一种接近线性的勘探，其数据采集线包括震源和接收器。针对这种情况，我们提出了一种二维介质中三维地震波场的2.5维模拟方法。计算机内存需求和计算时间仅略大于2D计算。我们证明了该技术的有效性和效率的数值例子，包括一个剖面横跨一个现实的模型俯冲带结构。

In this study we developed efficient numerical methods for modeling seismic waveforms in seismic exploration.In the first year we developed a very efficient procedure to calculate plane-wave responses of arbitrary 1-D media, such as gradient velocity or randomly heterogeneous structures, using the finite-difference method in the time domain (FDTD). This may be useful for analysis of reflection survey or seismic logging data.In the second year we developed an ultra efficient method for modeling seismic waveforms in refraction or wide-angle reflection surveys. The most common form of seismic exploration remains a nearly linear survey with data acquisition lines including the source and receivers. For this situation we developed a 2.5-D modeling method for the simulation of 3-D seismic wavefields in media varying in two dimensions. The computer memory requirements and computation time are only slightly larger than those for 2D computations. We demonstrated the validity and efficiency of the technique with numerical examples, including a profile across a realistic model of subduction zone structure.