In this note, I present an analytical procedure to estimate an initial value of
that depends only on the most basic processing scheme, the NMO stacking
process. Several authors have discussed the stacking process
for converted waves Castle (1988); Huub Den Rooijen (1991); Iverson et al. (1989); Tessmer and Behle (1988).
Tessmer and Behle (1988) apply
conventional NMO to converted waves where the RMS stacking
velocity is designated as the *converted-wave* velocity.
This NMO procedure uses a hyperbolic approximation
of the moveout equation; so, there is not
a satisfactory correction of the moveout.

I introduce a non-hyperbolic moveout equation that characterizes converted waves. This moveout equation consists of three main terms. The third term depends on the function giving us an equation to estimate an approximately constant value of , directly from the PS data alone.

10/23/2004