A frequency domain inversion method applied to oblique reflected signals from a water-sediment interface

Due to the complexity of the seafloor as an acoustical system, it is very i mportant to validate wave propagation models and test inversion methods fir st in the laboratory. A known sediment is placed in a water-filled tank, in such a way that a smooth water-sediment interface is obtained with minimal air bubbles retained in the sediment. Two broadband piston transducers are used to carry out reflection experiments at oblique incidence. The placeme nt of the emitter and receiver is symmetrical with respect to a vertical pl ane perpendicular to the sediment surface. The aim of this work is to find physical parameters of the sediment from the reflected signals. A general v iscoelastic model that considers losses due to absorption and dispersion al ong the propagation of the wave through the sediments is proposed. A ration al transfer function is used to model the viscoelastic modulus of the bulk sediments and a comparison with constant Q viscoelastic modelling is perfor med. The estimation of the model parameters is elaborated using a Maximum L ikelihood Estimator in the frequency domain.