Numerical Simulation Of Seismic Wave Propagation By Pseudospectral Method

In the process of seismic exploration,the inhomogeneity of underground medium is common.The complex distribution of underground medium brings many challenges to seismic physics and seismic exploration.It is always a difficult problem to eliminate the influence of inhomogeneity of underground medium on seismic exploration data.The complex underground medium will have a great impact on the propagation mode of seismic wave,which will cause the scattering and diffraction of body wave and surface wave,the mutual conversion between various wave types,waveform distortion,and make the wave field more complex.Therefore,it is necessary to simulate seismic wave propagation in inhomogeneous and complex media.The staggered grid pseudospectral method can effectively eliminate the numerical artifacts emerged in the simulation results of the standard grid pseudospectral method,so in this paper,the staggered grid pseudospectral method is used to solve the first-order velocity and stress equations of isotropic and anisotropic media in two-dimensional scale,and then combined with a variety of models for characteristic analysis.In order to further improve the accuracy of seismic forward numerical simulation,the twodimensional isotropic medium model is compared with the three-dimensional isotropic medium model.It still needs a lot of computing time and other hardware resources to solve the equation in three-dimensional isotropic medium model and carry out the integrity of the three-dimensional elastic wave numerical simulation,but the two-dimensional elastic wave numerical simulation can not accurately reflect the response of complex underground media to seismic waves,so we use the time staggered grid difference pseudospectral method to calculate the three-dimensional elastic wave field in the two-dimensional isotropic medium,that is,2.5D Instead of 2D numerical simulation.The results of wave field snapshots,wave profile and seismic records are compared.The 2.5D isotropic medium model is extended to anisotropic medium,which is a combination of the two,and further improves the high accuracy and efficiency of staggered grid pseudospectral method.