论文部分内容阅读
优化的近似解析离散化(ONAD)方法是近年来发展的一种新方法.与被普遍使用的有限差分方法相比,这类方法充分利用了位移梯度所包含的波场信息,使得该类方法在粗网格下能够有效地压制数值频散.本文给出求解二维球坐标系下SH波方程的ONAD方法.为了调查球坐标系下该算法的精度和计算效率,选取均匀介质和IASP91非均匀介质模型,分别给出了这两种情况下ONAD方法的计算结果,并与其他算法做了比较.结果表明,ONAD方法在求解球坐标系下SH波方程时具有弱数值频散、储存量小以及计算速度快的优点.作为应用,本文模拟了SH波在地表和地幔边界(CMB)之间的传播,得到了不同时刻的波场快照以及合成地震记录,并通过对波场快照和地震记录的分析,研究了SH波在地幔中的地震传播.
The optimized approximate analytical discretization (ONAD) method is a new method developed in recent years.Compared with the commonly used finite difference method, this kind of method makes full use of the wave field information contained in the displacement gradient, In the coarse grid can suppress the numerical dispersion effectively.In this paper, the ONAD method for solving the SH wave equation in two-dimensional spherical coordinate system is given.In order to investigate the accuracy and computational efficiency of the algorithm in the spherical coordinate system, the uniform medium and IASP91 non-uniform Medium model, the results of the ONAD method in these two cases are given respectively and compared with other algorithms. The results show that the ONAD method has the weak numerical dispersion and the small storage when solving the SH wave equation in the spherical coordinate system And the advantage of high computational speed.In this paper, we simulate the propagation of SH wave between the surface and the boundary of the mantle (CMB), obtain the snapshots of the wavefield at different times and the synthetic seismograms, The seismic wave propagation of SH wave in the mantle was studied.