On the use of the Norwegian Geotechnical Institute's prototype seabed-coupled shear wave vibrator for shallow soil characterization - II. Joint inversion of multimodal Love and Scholte surface waves

Abstract

Seismic data generated by a novel, seabed-coupled, shear-wave vibrator (prototype) and recorded by a densely-populated, multicomponent ocean-bottom cable allowed several modes of propagation of Love and Scholte waves to be retrieved in a relatively wide frequency band. Both global dispersion curves and local dispersion curves are extracted in the frequency–wavenumber (f–k) domain and inverted with a multimodal joint Scholte and Love wave inversion algorithm. Monte Carlo inversion is used for a estimating the global S-wave velocity profile of the seabed sediments whereas laterally constrained inversion is used to detect lateral variations of the layer interface depths. The results are in agreement and allowed consistent full-waveform simulation to be performed. The investigation depth is limited to around 40 m due to the low shear wave velocities within the shallow clay layer.