Figure 1. On side-scan sonar images, rock, gravel, sand, and mud reflect acoustic energy differently and appear as various shades of gray printed by the instrument's recorder. The classification scheme above is unique and based on the acoustic reflectivity of the Maine inner continental shelf. The dominant "end member" (Rock, Gravel, Sand, or Mud) is abbreviated with a capitalized first letter. A less abundant, subordinate seafloor type is represented with a lower case letter (r, g, s, or m). For example, a predominantly rocky seabed with gravel infilling fractures is designated Rg. The sixteen combinations of seafloor types shown above are used for areas where side-scan sonar coverage exists and appear as bright colors on the map.

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Last updated on October 6, 2005

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