USGS Western Coastal and Marine Geology
Pacific Coastal & Marine Science Center

Fate of Dredge Disposal Material and Polluted Sediment, Offshore Honolulu, Hawaii

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Color 3D Perspective Views Of Oahu Southern Shelf

Computer generated images of the seafloor and coastal area of south Oahu showing seafloor relief and backscatter patterns. The colored patterns on the seafloor are a measure of acoustic energy that was backscattered during a multibeam survey conducted in 1998. Generally, the patterns denote geologic character of the seafloor with reddish-brown patterns showing higher levels of backscatter or greater hardness (outcropping rock or sand), whereas the greenish-yellow patterns indicate less energy returned from the seafloor and therefore probably softer areas (muddy sediment). The seafloor relief in the image is based on very accurate bathymetric data collected by the USGS in 1998 with a 30 KHz multibeam system. Vertical resolution of the data is on the order of 50 cm; horizontal resolution is water depth dependent and varies from 6 to 16 m. The black indicates seafloor areas not imaged in 1998. The land image is derived from a USGS digital elevation model (DEM).

Click on thumbnail for full-size image and description.

 

Western Mamala Bay
Western Mamala Bay (48 Kb)
Ewa Wall
Ewa Wall (87 Kb)
Central Mamala Bay
Central Mamala Bay (196 Kb)
Disposal Area
Disposal Area (170 Kb)
Koko Head Trend
Koko Head Trend (80 Kb)
East Oahu Bedforms
East Oahu Bedforms (76 Kb)

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For more information, please contact:
Michael E. Torresan

U.S. Geological Survey
345 Middlefield Road MS 999
Menlo Park, CA 94025



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U.S. Department of the Interior | U.S. Geological Survey | Western Coastal & Marine Geology
URL: http://walrus.wr.usgs.gov/mamalabay/3Dcolorperspectives/
Maintained by Laura Zink Torresan
Last modified 11 October 2005 (lzt)