CONTINUOUS AND ELASTIC CONSISTENT REFLECTION AND TRANSMISSION AT AN INTERFACE SEPARATING TWO PORO-VISCOELASTIC MATERIALS

The reflection/transmission (R/T) coefficients equation are derived for effective Biot waves. The radiation condition is illustrated to cause the unphysical discontinuities. Meanwhile, the continuity criterion is for the first time applied in the R/T coefficients calculation for poro-viscoelastic waves. The continuity criterion is simply suggested to be conducted in the complex vertical slowness square (q²) plane by swapping the sign of q for the relevant wave whose q² locus crosses the branch-cut. Furthermore, the elastic consistence is also for the first time considered for poro-viscoelastic waves. We stress the importance of consistence between the R/T coefficient equations of poro-viscoelastic waves and those of pure elastic waves, which includes three consistent assumptions: time dependence of harmonic waves; z-direction of the coordinate system and particle motion (polarization) vectors. The example R/T coefficients of homogeneous S waves incidency are investigated for frequencies 1000 Hz and 0.001 Hz, representing highly and weakly dissipative poro-elastic waves, respectively. The calculated R/T coefficients are shown to be continuous without unphysical discontinuity under the continuity criterion. The R/T coefficients of poro-viscoelastic waves with 0.001 Hz well match the corresponding coefficients of elastic waves in terms of amplitudes and phases, and thus the elastic consistence is well confirmed.