During reverse time migration in anisotropic media, P- and SV-waves are coupled and the elastic wave equation should be used. However, the crosstalks caused by the interference between different wave modes are detected. Even if an acoustic anisotropic wave equation is used instead, an undesired SV-wave energy could be generated during modeling and reverse time migration. To avoid this unwanted energy, we proposed an approximation of decoupled P-and SV- wave equation system for vertical transversely isotropic (VTI) media. The qP- and qSV- phase velocities for the approximated equations are plotted and compared with the exact and other approximations, which proves its accuracy with different Thomsen parameter sets. The H-PML in second order wavenumber domain is also proposed to eliminate the artificial boundary reflections, comparisons of different absorbing boundary layers are also illustrated to validate the wave number domain H-PML.
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