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Quantitative morphology of a fringing reef tract from high-resolution laser bathymetry: Southern Molokai, Hawaii

Geological Society of America Bulletin

By:
, ,
DOI: 10.1130/B25200.1

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Abstract

High-resolution Scanning Hydrographic Operational Airborne Lidar Survey (SHOALS) laser-determined bathymetric data were used to define the morphology of spur-and-groove structures on the fringing reef off the south coast of Molokai, Hawaii. These data provide a basis for mapping and analyzing morphology of the reef with a level of precision and spatial coverage never before attained. An extensive fringing coral reef stretches along the central two-thirds of Molokai's south shore (???40 km); along the east and west ends there is only a thin veneer of living coral with no developed reef complex. In total, ???4800 measurements of spur-and-groove height and the distance between adjacent spur crests (wavelength) were obtained along four isobaths. Between the 5m and 15m isobaths, the mean spur height increased from 0.7 m to 1.6 m, whereas the mean wavelength increased from 71 m to 104 m. Reef flat width was found to exponentially decrease with increasing wave energy. Overall, mean spur-and-groove height and wavelength were shown to be inversely proportional to wave energy. In high-energy environments, spur-and-groove morphology remains relatively constant across all water depths. In low-energy environments, however, spur-and-groove structures display much greater variation; they are relatively small and narrow in shallow depths and develop into much larger and broader features in deeper water. Therefore, it appears that waves exert a primary control on both the small and large-scale morphology of the reef off south Molokai.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Quantitative morphology of a fringing reef tract from high-resolution laser bathymetry: Southern Molokai, Hawaii
Series title:
Geological Society of America Bulletin
DOI:
10.1130/B25200.1
Volume
115
Issue:
11
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geological Society of America Bulletin
First page:
1344
Last page:
1355
Number of Pages:
12