This paper studies the reflection and transmission of plane elastic
waves at interfaces in fluid-saturated poroviscoelastic media in
which the solid matrix is composed of two weakly coupled solids.
The analysis of this problem, not formally performed before, is based
on a theory recently developed by some, of the authors, which allows
us to derive expressions for the reflection and transmission coefficients
at a plane interface within this kind of media and their relationship
with the energy flux (Umov-Poynting) vector. The results of the present
derivation were applied to study the energy splitting that takes
place when a plane fast compressional wave strikes obliquely an interface
defined by a change in ice content within a sample of water saturated
partially frozen sandstone. The numerical results show wave mode
conversions from fast to slow compressional and shear waves, with
maximum energy conversion on the order of 20% from fast to slow wave
modes near the critical angle. This phenomenon was observed at frequencies
lying from the seismic to the ultrasonic range, showing that the
role of the slow waves must be taken into account when considering
wave propagation in this type of media.