Scattering from a rough sedimental seafloor containing shear and layering, as determined by perturbation theory
First-order perturbation theory is applied to reverberation from a rough sedimental seafloor. In addition to existing approaches, the seafloor is allowed to be shear-supporting or to be layered. Scattering strengths are derived for both monostatic and bistatic reverberation, and compared with results from a non-layered fluid bottom. By exceeding some 350 ms-1, shearwave velocity significantly influences scattering strength for angles below the critical angle of total reflection. Layering, as modelled by a two-layer fluid seafloor, mainly influences scattering at grazing angles just above critical.