Modeling Acoustic Interface Wave Dispersion Using COMSOL Multiphysics®

B. Goldsberry[1], M. Isakson[1]
[1]Applied Research Laboratories, The University of Texas at Austin, Austin, TX, USA

Measuring geoacoustic parameters of underwater sediments is important for accurate modeling of underwater acoustic propagation. While the density and compressional wave speeds can be directly measured in sediments, shear wave speeds are difficult to measure because they are highly attenuated. However, shear wave speeds can be indirectly determined through measurement of Scholte interface wave speeds. When the seafloor is composed of layers of sediments with different shear wave speeds, the Scholte wave speed becomes dispersive. Scholte wave speed dispersion was measured in the Narragansett Bay, RI. By using an inversion process, each layer’s shear wave speeds were calculated.

For validation, COMSOL Multiphysics® is employed to model the experiment at Narragansett Bay. The modeled and measured interface wave speeds are then compared.