Acoustic Techniques for Imaging the Seafloor
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The recent development of sophisticated sonar systems for seafloor imaging allows analyses of terrain beyond simple bathymetric mapping. The SEA-BEAM multibeam sonar system produces fullcoverage 12-kHz soundings, and much of the Gorda Ridge has been surveyed by the National Oceanic and Atmospheric Administration and the U.S. Navy. Complete-coverage digital bathymetry provides the basic data for statistical modeling of seafloor roughness through spectral and fractal mathematical techniques. In addition to soundings, the SEABEAM system can provide fundamental information about bottom properties through evaluation of the backscattered acoustical signal. Side-scan sonar systems allow more detailed observations of the variability of acoustic properties. Available sidescan sonar data range from the broad (60-km swath) complete coverage of the GLORIA system collected by the U.S. Geological Survey to 10-km swath Sea-MARC II and 5- to 0.5-km-wide SeaMARC I imaging, which produces pixel spot sizes of as little as 25 cm. The full-coverage, digital nature of these data allows the application of terrain classification techniques developed for satellite imagery. The validity of remote-imaging techniques can only be evaluated when compared to observational ground truth. A recently developed technique for geological mapping from bottom photography facilitates such comparisons.
KeywordsSonar System Acoustic Technique Sidescan Sonar Fuca Ridge Bathymetric Chart
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- Chase TE, Wilde P, Normark WR, Miller CP, Seckins DA, Young JD (1981) Offshore Topography of the Western United States between 32° and 49° North Latitudes, Plate 2. U.S. Geological Survey Open-File Map 81:433.Google Scholar
- Clague DA, Holmes ML (1987) Geology, petrology, and mineral potential of the Gorda Ridge. In: Scholl DW, Grantz A, Vedder JG (eds) Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Ocean Basins—Beaufort Sea to Baja California. Houston: Circum-Pacific Council for Energy and Mineral Resources Earth Science Series 6:563–580.Google Scholar
- EEZ SCAN Scientific Staff (1986) Atlas of the Exclusive Economic Zone, Western Conterminous United States. U.S. Geological Survey Miscellaneous Investigations Series I–1792, 152 pp, scale 1:500,000.Google Scholar
- Elvers DJ, Potter KW (1971) NOS SEAMAP Planning Report. International Hydrographic Bulletin.Google Scholar
- Little SA, Purdy GM, Stolzenbach KD (1986) Acoustic monitoring of hydrothermal vent fields. EOS 67/44:1232.Google Scholar
- Malahoff A (1985) Hydrothermal vents and polymetallic sulfides of the Galapagos and Gorda/Juan de Fuca Ridge systems and of submarine volcanoes. Bull Biol Soc Wash 6:3–18.Google Scholar
- Mandelbrot B (1982) The Fractal Geometry of Nature. San Francisco: W.H. Freeman, 460 pp.Google Scholar
- Tyce RC (1986) Deep seafloor mapping systems—a review. Marine Technol Soc J 20/4:4–16.Google Scholar
- van Wyckhouse RJ (1973) Synthetic Bathymetric Profiling System (SYNBAPS). Bay St. Louis, MS: Naval Oceanographic Office Technical Report TR-233.Google Scholar