Numerical, Theoretical and Experimental Studies of Seafloor and Subseafloor Reverberation
Abstract
In studies of low-frequency reverberation within the marine environment, a central concern is the relationship between reverberation events and morphological features of the seafloor. A time-domain migration algorithm for the reverberation intensity field is developed that produces scattering coefficient maps coregistered with a bathymetry database. The algorithm is tailored to broadband transient sources with good range resolution, and was developed to analyze an extensive set of reverberation records from a 200-255 Hz source collected on the flanks of the Mid-Atlantic ridge. The precise, sample-by-sample, tracking of wavefronts across elements of the bathymetry database that forms the foundation of the algorithms implementation results in reverberation maps that show a clear and detailed correlation between scattering and morphology with narrow scarp slopes consistently highlighted. Environmentally induced asymmetries in transmission loss and incidence angle are exploited to break the inherent left-right ambiguity of the receiver array. Iterative migration, assuming a dominant dependence of backscatter on grazing angle, produces images, even from individual records, that show good ambiguity resolution. Results from multiple records corroborate the effectiveness of the ambiguity resolution and demonstrate the stability of the scattering coefficient estimates and the acoustic system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 19, 2000
- Accession Number
- ADA376838
Entities
People
- Alistair J. Harding
- John A. Orcutt
- Michael A. Hedlin
Organizations
- Scripps Institution of Oceanography