Determination of Shear-wave Velocity in Seabed from Dispersion Data of Love Waves

Estimation of the shear (S-) wave velocity or shear strength in the seabed is of importance for geotechnical applications, characterization of subsurface, seismic exploration studies and geohazard investigation. S-wave velocities in the sediment can be estimated by invert the dispersion data of seismic interface waves, which will be considered in this study. Numerical study shows that Love wave sensitivity and inversion stability in linearized inversion is higher than that of the Rayleigh wave and the inversion of Love wave dispersion curve provides a more accurate results. However, in conventional underwater seismic experiments only Scholte wave can be generated. In a testing experiment S-wave sources were used and both Scholte wave and Love wave were generated and recorded. In this study the dispersion of Love waves are analyzed using three time-frequency analysis methods. The S-wave velocities are estimated by inverting the dispersion data. The inversion results show the maximum penetration depth of the estimates is around 25 m in the seafloor, where the estimated S-wave velocity is around 220m/s. This approach provides an alternate and supplementary means to estimate the seismic velocity structure that is valuable in both seafloor geotechnical engineering and the static correction in seismic exploration using reflection methods.