Zhang (1993) brings theoretical insight into the problem of improving the amplitudes of downward continuation operators. Zhang et al. (2001) compare them with Kirchhoff inversion and provide formulas for amplitude-preserving shot-profile migration that are accurate in the case of constant velocity. Along the same lines, Zhang et al. (2002) give an additional term for the case of velocity varying only with depth. Zhang et al. (2003a) extend the argument to heterogeneous media. Besides that, Zhang et al. (2003b) provide a more accessible description of the basic theory of the method. In this paper, we describe implementations of this amplitude-preserving downward continuation operators in the domain (finite-difference), as well as in the mixed domain.

7/8/2003