Acoustic and Elastic Scattering from Seamounts in Three Dimensions - A NumericalModeling Study. (Reannouncement with New Availability Information)

摘要

A three-dimensional (3-D) finite difference elastic wave propagation numericalmodel is used to study the acoustic scattering in the water column and the elastic scattering in the subbottom from seamounts (conical hills) located on the ocean floor. Two models are investigated: scattering from a single seamount located on a flat seafloor, and scattering from two seamounts on an otherwise flat seafloor. In both cases a point source of acoustic energy is introduced in the water column, and particular attention is paid to the backscattered acoustic energy that emanates from the seamount features. The results indicate that in addition to the expected scattering off the front and back faces of the seamount, additional energy is radiated onto the water column from reverberations inside the seamount and the related interface energy that propagates around the circumference of the seamount. Comparison of the single seamount and two seamount models suggests that the effect of multiple features is an increase in the overall level of backscattered acoustic energy. A comparison between the 3-D single seamount model and a two-dimensional (2-D) simplification is also presented. The 3-D model results in a more complicated backscattered wave field due to the effects of the seamount resonant and circumferential modes which are lost in 2-D representations. Elastic scattering in the subbottom due to seamount features is also illustrated.... Acoustic, Scattering, Finite difference.