Spatial Variability of Seafloor and Shallow Sub-surface Acoustic Properties, Shallow Water Gulf of Mexico
Abstract
In June 2007 we carried out the first of two ONR field programs aboard the R/V 'Pelican' designed to evaluate variations in seafloor and shallow sub-surface acoustic properties at three sites in the northern Gulf of Mexico. The follow-up field program is scheduled for January, 2008, and will use the same boat and same systems to survey the same sites to determine whether there are any seasonal variations in the datasets as well spatial variability between the sites. Data acquisition includes multibeam bathymetry, multibeam backscatter, side scan sonar, and sub-bottom profiling. In addition to temporal (seasonal) and spatial variations, we are examining the differences in acoustic signature of the seafloor at different frequencies. The three areas of interest in this two-year program are: (1) off the coast of Louisiana, west of Atchafalaya Bay, at the site of the ONR multi-year research program 'Mechanism of Fluid-Mud Interactions Under Waves' (MURI), (2) off Panama city, Florida in an area of known sub-surface features and (3) off Louisiana's Southwest Pass in an area of where mudflows triggered by Hurricanes Ivan and Katrina destroyed or damaged platforms and pipelines (West Delta). Water depths in the areas of interest range from 3.5 to 96 m. Preliminary analysis of the data indicates spatial differences between and within the sites. Within individual sites there are differences in the data as a function of the frequencies used to map the seafloor. Off Southwest Pass we find differences in mudflow character associated with a known dredge site suggesting a possible anthropogenic component to mudflow sourcing and level of activity.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMNS31B0396O
- Keywords:
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- 3002 Continental shelf and slope processes (4219);
- 3020 Littoral processes;
- 3022 Marine sediments: processes and transport;
- 3045 Seafloor morphology;
- geology;
- and geophysics;
- 4259 Ocean acoustics