一种基于非规则网格的地震波射线追踪方法

地震波走时计算对地震资料层析速度建模、偏移成像及地震定位等研究都具有非常重要的意义。有限差分法计算地震波走时具有计算效率高、易于实现、准确性高的优点,因而得到广泛应用。针对规则网格有限差分方法处理尖锐速度界面时存在不足的问题,提出了一种非规则网格的有限差分走时计算方法,即在Vidale差分算式的基础上推导出不规则网格差分算式,使其适用于不同的网格剖分方式。对均匀介质模型、复杂模型和Marmousi模型试算的结果表明，改进的方法能较好地解决尖锐速度界面和首波走时计算问题,且对复杂速度模型具有较好的适应性。

 The calculation of seismic wave traveltime is very important for the study of velocity modeling by seismic data tomography,migration imaging and seismic positioning. Finite difference method is widely used to calculate seismic traveltime due to its advantages of high computational efficiency,easy to achieve and high accuracy. Finite difference method based on regular grids is no good at treating sharp velocity interface and in view of this problem,a finite difference method based on irregular grids is proposed to calculate traveltime. The results show that the improved method can solve the problem of treating sharp velocity interface and calculating head wave traveltime,with a better adaptability for complex velocity models.