Reflection/Transmission Coefficients at a Plane Interface in Dissipative and Nondissipative Isotropic Media: A Comparison.

The problem of reflection/transmission of plane waves in homogeneous isotropic dissipative media is investigated. In dissipative media, the elastic moduli, seismic velocities and slowness vectors are complex-valued and frequency-dependent. Results of extensive computations of R/T coefficients for plane waves incident at a plane interface are presented and discussed. In all cases, the "reference R/T coefficients" are considered, computed for a fixed frequency equal to the reference frequency f[sub r], for which the elastic moduli are specified. The influence of angle of incidence i and attenuation angle gamma; of the incident wave on the coefficients is studied in detail. In general, the differences between the moduli of the R/T coefficients for dissipative and nondissipative models are usually small for realistic Q's and γ's. These differences are more distinct in critical and post-critical regions for the reflection coefficients, particularly for small Q's, large contrast of Q's across the interface, and for large ≈'s (say, γ > 50°). The differences between the phases of R/T coefcients for dissipative and nondissipative media may be larger. For some γ's, the signs of the phases for dissipative and nondissipative media may be roughly opposite, even for very high Q's. [ABSTRACT FROM AUTHOR]