Geoacoustic inversion using vector acoustic modal dispersion: a sensitivity study

Geoacoustic inversion is traditionally performed using sound pressure data. In this paper, we present a sensitivity study of geoacoustic inversion using particle velocity, as recorded on a single vector sensor. The scope of the study is further restricted to shallow water and low-frequency impulsive sources. If propagating modes can be separated, then four vector acoustic metrics can be formed by coherent combination of pressure and velocity: phase speed, circularity, depth-dependent mode speed of energy, and vertical component of normalized reactive intensity. Each of these vector metric can be used as an input for geoacoustic inversion. Their sensitivity to seabed geoacoustic parameter is illustrated on a simulated scenario that reproduce the Seabed Characterization Experiment (SBCEX) that took place on the New England Mud Patch in 2017. Results are compared with inversion results obtained using group speed as input data. All the vector metrics but phase speed have a better sensitivity to seabed parameters than modal group speeds.