Optimal Parameter Values Of Perfectly Matched Layer For Seismic Wave Simulation

The simulation of seismic wave has a very important role in the study of seismology.The grid-based finite difference method has become one of the most commonly used methods in seismic wave simulation because it is easy to implement and has high computational efficiency.In the real seismic wave propagation process,the seismic wave does not have the reflection wave in the position where the medium parameter does not change.However,due to the limited space size of the discrete grid,the outermost layer of the calculation model can produce artificial reflection that affects the calculation results.Because of the existence of artificial reflection,the seismic waves need to be processed at the boundary of the calculation area to obtain numerical simulation results that are closer to the real situation.The perfectly matched layer method has good absorption effect,high efficiency and wide application range.It has been widely used in waveform modeling.In this paper,we first introduce the first-order velocity-stress elastic wave equation of the two-dimensional P-SV wave,the finite difference method of the staggered grid and the expression of the standard perfectly matched layer and the complex frequency-shifted PML(CFS-PML)based on the auxiliary differential equations.Then,the parameter selection scheme of CFS-PML is discussed by using the above-mentioned methods,and a set of superior parameter selection methods are given respectively.Based on this,the setting method of multi-axial CFS-PML(CFS-MPML)is discussed.A possible setting method of CFS-MPML is proposed to reduce artificial reflections while ensuring the absorption effect.Many studies have discussed the optimal setting of the CFS-PML parameters,but they only consider the homogeneous velocity model.For real applications,the velocity model commonly contains strong heterogeneities.In this paper,the CFS-PML parameter setting method of complex velocity model is analyzed and tested,and the setting method of CFS-PML optimization parameter of complex velocity model is proposed,which provides a reference for the numerical simulation of seismic waves with the actual complex velocity model.