In homogeneous transversely isotropic media with a vertical symmetry axis (VTI media),
*P*- and *SV*-waves ^{} can be described by the vertical velocities
*V*_{P0} and *V*_{S0} of *P*- and *S*-waves, respectively, and two
dimensionless parameters and Thomsen (1986).
Tsvankin and Thomsen (1994) and Alkhalifah (1997a) demonstrated that *P*-wave velocity and
traveltime are practically independent of *V*_{S0}, even for strong anisotropy.
Thus, for practical purposes, *P*-wave kinematic signatures can be considered
a function of just three parameters: *V*_{P0}, , and .

Alkhalifah and Tsvankin (1995) further demonstrated that a new representation in terms of just two parameters is sufficient for performing all time-related processing, such as normal moveout correction (including nonhyperbolic moveout correction, if necessary), dip-moveout removal, and prestack and post-stack time migration, assuming that the velocity varies only vertically. These two parameters are the normal-moveout velocity for a horizontal reflector

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10/9/1997