Approximate PP and PS reflection/transmission coefficients for weak- contrast interfaces in general weakly anisotropic media are presented. The coefficients were obtained by applying the first-order perturbation theory and they are written in a compact and relatively simple form. The formulae can be used for arbitrary orientations of the incidence plane and the interface without transforming elasticity parameters to a local Cartesian coordinate system. The accuracy of the approximate formulae is illustrated on the PS reflection coefficient. Comparison of the exact and approximate coefficients shows that the approximate formulae are sufficiently accurate for a wide range of incidence angles and for all azimuths.
The paper is available in PostScript (6276 kB !) and GZIPped PostScript (547 kB).