Paper Summary
In the implementation of TTI RTM, we meet stability problems and demands for speedup. Staggered Fourier first derivative and linear interpolation improves stability and accuracy. Areas with high gradients of the symmetry axis give rise to unstable numerical computations and make the wavefield blow up. Selective matching of anisotropy parameters helps to eliminate these areas. The acoustic TTI wave equation needs intensive computing. The finite difference method is more flexible than pseudo-spectral method. However, the pseudo-spectral method gives a more accurate solution than the finite difference method. Efficiency can be improved by combining pseudo-spectral and finite difference methods.