Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer
Measurements of low-frequency sound propagation over the areas of the Australian continental shelf, where the bottom sediments consist primarily of calcarenite, have revealed that acoustic transmission losses are generally much higher than those observed over other continental shelves and remain rel...
| Main Authors: | , , , , |
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| Format: | Journal Article |
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American Institute of Physics
2013
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| Online Access: | http://hdl.handle.net/20.500.11937/15173 |
| _version_ | 1848748821930049536 |
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| author | Duncan, Alec Gavrilov, Alexander McCauley, Robert Parnum, Iain Collis, J. |
| author_facet | Duncan, Alec Gavrilov, Alexander McCauley, Robert Parnum, Iain Collis, J. |
| author_sort | Duncan, Alec |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Measurements of low-frequency sound propagation over the areas of the Australian continental shelf, where the bottom sediments consist primarily of calcarenite, have revealed that acoustic transmission losses are generally much higher than those observed over other continental shelves and remain relatively low only in a few narrow frequency bands. This paper considers this phenomenon and provides a physical interpretation in terms of normal modes in shallow water over a layered elastic seabed with a shear wave speed comparable to but lower than the water-column sound speed. A theoretical analysis and numerical modeling show that, in such environments, low attenuation of underwater sound is expected only in narrow frequency bands just above the modal critical frequencies which in turn are governed primarily by the water depth and compressional wave speed in the seabed. In addition, the effect of a thin layer of harder cap-rock overlaying less consolidated sediments is considered. Low-frequency transmission loss data collected from an offshore seismic survey in Bass Strait on the southern Australian continental shelf are analyzed and shown to be in broad agreement with the numerical predictions based on the theoretical analysis and modeling using an elastic parabolic equation solution for range-dependent bathymetry. |
| first_indexed | 2025-11-14T07:11:08Z |
| format | Journal Article |
| id | curtin-20.500.11937-15173 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:11:08Z |
| publishDate | 2013 |
| publisher | American Institute of Physics |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-151732017-09-13T15:04:06Z Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer Duncan, Alec Gavrilov, Alexander McCauley, Robert Parnum, Iain Collis, J. calcarenite low-frequency continental shelf Measurements of low-frequency sound propagation over the areas of the Australian continental shelf, where the bottom sediments consist primarily of calcarenite, have revealed that acoustic transmission losses are generally much higher than those observed over other continental shelves and remain relatively low only in a few narrow frequency bands. This paper considers this phenomenon and provides a physical interpretation in terms of normal modes in shallow water over a layered elastic seabed with a shear wave speed comparable to but lower than the water-column sound speed. A theoretical analysis and numerical modeling show that, in such environments, low attenuation of underwater sound is expected only in narrow frequency bands just above the modal critical frequencies which in turn are governed primarily by the water depth and compressional wave speed in the seabed. In addition, the effect of a thin layer of harder cap-rock overlaying less consolidated sediments is considered. Low-frequency transmission loss data collected from an offshore seismic survey in Bass Strait on the southern Australian continental shelf are analyzed and shown to be in broad agreement with the numerical predictions based on the theoretical analysis and modeling using an elastic parabolic equation solution for range-dependent bathymetry. 2013 Journal Article http://hdl.handle.net/20.500.11937/15173 10.1121/1.4809723 American Institute of Physics fulltext |
| spellingShingle | calcarenite low-frequency continental shelf Duncan, Alec Gavrilov, Alexander McCauley, Robert Parnum, Iain Collis, J. Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| title | Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| title_full | Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| title_fullStr | Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| title_full_unstemmed | Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| title_short | Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| title_sort | characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer |
| topic | calcarenite low-frequency continental shelf |
| url | http://hdl.handle.net/20.500.11937/15173 |