Three-dimensional raytrace modeling of the New England seamounts acoustics experiment

Abstract

The 2023 New England Sea Mounts Acoustics (NESMA) experiment took place from April to June at the Atlantis II Seamount Complex. One goal NESMA seeks to address is to further the understanding of acoustic propagation around prominent bathymetric features and associated diffraction and refraction effects. The bathymetry of the experimental site exhibits extreme variability with a difference in elevation of three kilometers from the abyssal plane to the peaks of the seamounts and slopes upwards of 15°, which has a significant influence on bottom-interacting acoustic propagation. As part of the experiment, multiple broadband impulsive sound sources were deployed around the seamounts, including explosive charges, seismic air-gun, and rupture induced cavitation events. Three-dimensional ray trace models of the experiment are presented for comparison with the measured acoustic receptions. Model results are primarily concerned with signals received on three single-channel acoustic recorders deployed on the abyssal plane near the seamounts. Comparisons provide insight into variation in the structure of the measured arrivals associated with varying ray paths refracted around and between the seamounts for different source positions. The influence of geotechnical properties on the measured signals is also assessed through modeling. [Work supported by ONR.]