Investigation of spatial and temporal environmental variability on acoustics in the New England Mud Patch

Numerous experiments have been conducted at the New England Mud Patch (NEMP) over the course of the last decade. Previous research, including core measurements and geo-acoustic inversion efforts, indicates that the seabed in the region is comprised of three distinguishable sediment layers resulting from millennia of fine-grained sediment accumulation. These layers are defined as follows: a fluid-like mud layer (layer 1), a more rigid mud layer that lies beneath (layer 2), and a sand layer of approximately 10 m (layer 3). These layers overlie a higher speed basement. Within the irregularly shaped area of the mud patch, the thickness of the second mud layer varies substantially, often ranging from 6 to 16 m. To better understand the spatial and temporal variability of acoustic propagation throughout the environment, data from the Seabed Characterization Experiment 2017 (SBCEX17) and 2022 (SBCEX22), are analyzed. This study specifically investigates the impact of range dependency and shear properties on acoustic propagation using an elastic parabolic equation model. The high-fidelity model is particularly suited for accounting for complex acoustic–elastic interactions and jump discontinuities within the seabed. Model predictions will be compared with experimental data to validate our understanding of acoustic propagation in muddy environments.