Depth and frequency dependence of geoacoustic properties on the New England Mud Patch from reflection coefficient inversiona)

Yong-Min Jiang; Charles W Holland; Stan E Dosso; Jan Dettmer

doi:10.1121/10.0021309

Depth and frequency dependence of geoacoustic properties on the New England Mud Patch from reflection coefficient inversiona)

J Acoust Soc Am. 2023 Oct 1;154(4):2383-2397. doi: 10.1121/10.0021309.

Authors

Yong-Min Jiang¹, Charles W Holland², Stan E Dosso¹, Jan Dettmer³

Affiliations

¹ School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada.
² Department of Electrical and Computer Engineering, Portland State University, Portland, Oregon 97201, USA.
³ Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada.

PMID: 37850832
DOI: 10.1121/10.0021309

Abstract

Muddy sediments cover significant portions of continental shelves, but their physical properties remain poorly understood compared to sandy sediments. This paper presents a generally applicable model for sediment-column structure and variability on the New England Mud Patch (NEMP), based on trans-dimensional Bayesian inversion of wide-angle, broadband reflection-coefficient data in this work and in two previously published reflection-coefficient inversions at different sites on the NEMP. The data considered here include higher frequencies and larger bandwidth and cover lower reflection grazing angles than the previous studies, hence, resulting in geoacoustic profiles with significantly better structural resolution and smaller uncertainties. The general sediment-column structure model includes an upper mud layer in which sediment properties change slightly with depth due to near-surface processes, an intermediate mud layer with nearly uniform properties, and a geoacoustic transition layer where properties change rapidly with depth (porosity decreases and sound speed, density, and attenuation increase) due to increasing sand content in the mud above a sand layer. Over the full frequency band considered in the new and two previous data sets (400-3125 Hz), there is no significant sound-speed dispersion in the mud, and attenuation follows an approximately linear frequency dependence.