Forward modeling of the seismic wave field of pure qP waves in TTI media based on the pseudo-analytical method
Forward modeling and reverse-time migration imaging techniques for pure quasi-P(qP)waves in anisotropic media have a-roused extensive concern in recent years.However,conventional quasi-acoustic equations are subjected to the interference from quasi-shear waves,the limitation of model parameters(ε≥δ),propagation instability,and low calculation accuracy,thus significantly restric-ting their application.Hence,this study shifted the quasi-differential equation of qP waves to the space-wavenumber domain and derived the second-order pure qP wave equation of TTI media in the time domain through coordinate transformation.To improve the calculation accuracy,this study conducted the forward modeling of the seismic wave field of pure qP waves in TTI media based on the pseudo-ana-lytical method(PAM).The numerical simulation results show that:(1)The method proposed in this study was free from the limitations of quasi-acoustic equations,the interference from quasi-shear waves,and model parameters,enabling stable propagation of the seismic wave field;(2)Compared to other methods,the PAM can effectively improve the numerical simulation accuracy;(3)The testing of sim-ple and complex models verified the correctness and applicability of the proposed method.
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