Numerical simulation of 2D three-component surface waves in TI media based on the rotated staggered grid
The finite difference method based on a standard staggered grid is widely used in the forward simula-tion of surface waves.The single use of the Rayleigh or the Love wave simulation method is no longer able to meet the surface wave simulation needs in the context of transversely isotropic(TI)media.Therefore,a two di-mensional three-component surface wave simulation method based on a rotated staggered grid(RSG)for TI media is proposed.Firstly,the first order velocity stress two-dimensional three component wave equation is adopted to combine the P-SV wave equation and SH wave equation.Next,the RSG finite difference method is combined with multi-axis perfectly matched layer technology to implement a two dimensional three-component surface wave simulation including Rayleigh wave simulation and Love wave simulation.Then,qualitatively and quantitatively compare the effect and accuracy of the RSG finite difference method and the standard stag-gered grid(SSG)finite difference method in the simulation of surface waves in two dimensional isotropic homo-geneous half-space media,in three aspects of wavefront snapshots,waveform curves,and dispersion curves.Finally,this method is applied to the two dimensional three-component surface wave simulation in homoge-neous half space TI media(including VTI,HTI,and TTI)and two layer velocity increasing TTI media.Through wavefield snapshots,seismic records,and dispersion energy diagram,the characteristics of surface waves in TI media and the effect of anisotropic parameters on surface wave dispersion characteristics are analyzed.The experimental analysis realizes the simulation of Rayleigh wave and Love wave with the same equation,which proves the applicability of the proposed method in surface wave simulation practice,and provides an im-portant reference for full-wave seismic wave simulation and even full-wave field inversion in two-dimensional cases.Moreover,it is of great significance for further understanding the propagation characteristics of surface waves in the anisotropic media.
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