Anelastic P-wave, S-wave and Converted-wave AVO Approximations

The purpose of this paper is to present approximate expressions for the AVO and amplitude-variation-with-frequency (i.e., AVF) behaviour of reflections from an anelastic target. We extend previous work to allow for P, S, and converted wave data to be analysed. By altering the Zoeppritz equations to incorporate a nearly constant Q model in the target medium, and linearizing, approximate forms for PP, PS and SS reflection coefficients with corrections for anelasticity are derived. Inversion of these data is straightforward, with the PS and SS modes preferentially useful for computing QS, and the PP mode preferentially useful for computing QP. We find that reciprocal QP and QS are proportional to the reflection coefficients’ frequency rate of change.