## First-order reflection/transmission coefficients
for unconverted plane P waves in weakly anisotropic media

**Veronique Farra** and
**Ivan Psencik**
### Summary

We present approximate formulae for the plane-wave, displacement reflection/transmission (R/T)
coefficients for interfaces of arbitrary contrast, separating two
homogeneous, weakly anisotropic media. In deriving them, we use first-order quantities,
with which we work when using first-order ray tracing (FORT) for inhomogeneous anisotropic
media. Specifically, the phase velocities, slowness and polarization vectors used are of
the first-order with respect to the deviations of anisotropy from isotropy.
The derived R/T coefficients transform an incident P
wave into a reflected/transmitted P or coupled S wave.
Coefficients can be computed for any incidence angle between 0^{0} and 90^{0},
and for any azimuth. In this paper, we test the accuracy of the derived R/T coefficients
of unconverted plane P waves. We show that, except for critical regions,
first-order coefficients approximate the exact coefficients with acceptable accuracy.

### Whole paper

The paper is available in
PDF (365 kB).

In: Seismic Waves in Complex 3-D Structures, Report 20,
pp. 77-102, Dep. Geophys., Charles Univ., Prague, 2010.