Sea-bottom properties play an important role in fields as diverse as underwater acoustics, earthquake and geotechnical engineering, and marine geophysics. Water-column acousticians study shear and interface waves in the nearbottom sediments with the aim of inferring sea-bed geoacoustic parameters for predicting reflection and absorption of waves at the sea floor. On the other hand, geotechnical engineers working on design and siting of offshore structures focus on these waves to characterize soil and rock properties. In the field of geophysics, sea-bottom parameters are of interest for several reasons. In conventional marine acquisition, these parameters determine the partitioning of the incident P-wave energy from the source into transmitted P-waves and mode-converted S-waves (Tatham and Goolsbee, 1984; Kim and Seriff, 1992). The sea-floor P- and S-wave velocities and density are also necessary inputs for decomposing multicomponent sea-floor data into P- and S-waves (Amundsen and Reitan, 1995a and b), as well as in the numerical study of wave propagation phenomena.