LAUSR

&NA; Based on the modified Biot theory of Johnson, the propagation characteristics of the various interface waves at an interface between a semi‐infinite fluid and a porous medium were studied. First, based on the characteristic equations of open‐pore and sealed‐pore, which were derived from the wave equations, time‐domain waveforms at the interface were obtained by inverse Fourier transform. The effects of the longitudinal frame modulus on the interface waves were investigated. For open‐pore and sealed‐pore, the effect of porosity on the propagation of the interface waves was studied; the porosity was found to strongly influence the true surface wave. Based on four ultrasonic suspension models—Utrick, Utrick‐Ament (UA), Harker–Temple (HT) and McClement, the pseudo‐Stoneley wave propagation characteristics were analyzed at the interface between the sediment‐containing two‐phase fluid and the porous medium solid. The effects of volume fraction and particle diameter on the phase velocity, attenuation coefficient and dispersion for the pseudo‐Stoneley and true surface wave were discussed, and the results demonstrated that the properties of the fluid strongly impacted the pseudo‐Stoneley wave but exerted very little effect on the true surface wave. The conclusions drawn in this paper could contribute to elucidate the parameters of sediment and porous media. HighlightsFocus on the effect of the fluid side characteristics on the interface waves.The porosity strongly influences the true surface wave. The sediment characteristics significantly influence the pseudo‐Stoneley wave.The conclusions drawn in this paper could contribute to elucidate the parameters of sediment and porous media.