** Next:** Stiffnesses perturbations
** Up:** IMAGING CONDITION
** Previous:** S-S reflection coefficient

For anisotropic media, it is necessary to make the distinction between
group and phase properties. The equations relating the several
reflection and transmission coefficients with the elastic properties
of the medium are derived for plane waves, which imply that
the coefficients are associated to ratios between *phase amplitudes*.
One possible approach is to perform a local plane-wave decomposition,
integrating the component of the vector-wavefield in the local polarization
direction () along different directions *p* in order to
build a function *A*(*p*,*x*,*z*,*t*), which represents the phase amplitude for
each point of the space-time as a function of the horizontal slowness,
and a polarization vector function . Time averaging should
in this case provide three expectations:, ,
and . Next we need to use the Christoffel equation with
the background elastic parameters used in the migration to find the
wave type associated with each polarization vector. Then, an anisotropic
inversion scheme can estimate the elastic parameters that best fit
the scattering relation involving for the different modes
and , as a function of the horizontal slowness .

** Next:** Stiffnesses perturbations
** Up:** IMAGING CONDITION
** Previous:** S-S reflection coefficient
Stanford Exploration Project

11/18/1997