Surface waves in partially saturated porous media

Numerical results for the dispersion relation of surface wave modes in partially saturated porous media are presented in a broad band of frequencies (100 Hz - 200 kHz). A modified Biot theory of poromechanics is implemented which takes into account the interaction between the gas bubbles and the liquid and the solid phase of the porous material. The dependence of the frequency-dependent phase velocities and damping coefficients on the gas saturation are studied for flat and cylindrical interfaces between a liquid and a partially saturated porous medium. The attenuation of the pseudo-Stoneley wave increases with gas saturation in both configurations. In the cylindrical interface the radial penetration of the pore-pressure induced by the pseudo-Stoneley wave decreases with gas saturation due to compressibility effects