Explicit finite difference modeling for the acoustic scalar wave equation in TTI media with optimal operators

We have developed an explicit finite-difference modeling scheme for the scalar acoustic wave equation in tilted transverse isotropic (TTI) media, which is computationally efficient in terms of speed and memory and can be used for reverse time migration. Our method uses local spatial operators optimized in the least-squares sense by matching the discrete operator in the wavenumber domain. The calculated operator is applied locally to the wavefield in the space-time domain when the medium is TTI and turns into a conventional finite-difference operator when the medium is isotropic. Our wavefield modeling is stable with no limits such as ε< δ on anisotropic parameters and does not generate S-wave artifacts. The accuracy and the efficiency of our modeling scheme are demonstrated for homogeneous, two half-space TTI, and the BP 2007 TTI models.