ACCESS NUMBER: 30951-17800 

STUDY TITLE: Mapping Areas of Hard Bottom and Other Important Bottom Types: 

Outer Continental Shelf and Upper Continental Slope 

REPORT TITLE: Mapping Areas of Hard Bottom and Other Important Bottom Types: 

Outer Continental Shelf and Upper Continental Slope 

CONTRACT NUMBER: 1435-01-99-CA-30951-17800 

SPONSORING OCS REGION: Gulf of Mexico 

APPLICABLE PLANNING AREA: Central Gulf of Mexico 

FISCAL YEARS OF PROJECT FUNDING: 2000, 2001, and 2002 

COMPLETION DATE OF REPORT: December 2005 

COSTS: FY 2003 $83,432; FY 2004 $83,432; FY 2004 $83,433; CUMULATIVE 

PROJECT COST: $250,297 

PROJECT MANAGER: Harry H. Roberts 

AFFILIATION: Louisiana State University 

ADDRESS: Coastal Studies Institute, Louisiana State University, Baton Rouge, 

Louisiana, 70803 

PRINCIPAL INVESTIGATORS: Harry H. Roberts, James M. Coleman, and R. 

Hampton Peele 

KEY WORDS: Outer Continental Shelf, Hard Bottom 

BACKGROUND: Geophysical high-resolution acoustic data is routinely collected from 

the Gulf of Mexico continental shelf and slope to allow evaluations of geohazards prior 

to oil and gas development. A total of 182 blocks of geophysical data was contributed 

to the Coastal Studies Institute (CSI) by industry for analysis in the mid-1980’s. 

Although CSI has worked extensively with these original data sets on an individual 

basis, the data was not considered as a whole or processed into the useful Geographic 

Information System (GIS) format allowing evaluations and analyses of geohazards on a 

regional basis. 

OBJECTIVES: This project will organize and map previously separate and isolated 

data sets to produce useful regional maps of seafloor characteristics categorized in a 

logical and uniform way. 

DESCRIPTION: This project, conducted cooperatively through the Louisiana State 

University Coastal Marine Institute, was designed to convert existing seafloor maps 

compiled from high-resolution seismic profiles, side-scan sonar data, and bathymetry 

acquired in 182 OCS lease blocks to MMS-approved GIS format for use in geohazards 
ACCESS NUMBER: 30951-17800 

evaluations. Six mapping categories were used: (1) undisturbed seafloor, (2) seafloor 

erosion, (3) hard bottom areas (carbonate banks, bioherms, hardgrounds, and 

outcrops), (4) faults, (5) acoustic wipeout zones, and (6) mass movement features. In 

addition to converting existing maps, mapping of new 3-D seismic surface amplitude 

data filled many of the gaps in the high-resolution acoustic data sets. This project 

produced a set of seafloor maps from five mapping areas that can be used for planning 

activities in the OCS region of the northern Gulf of Mexico from the shelf edge to a 

depth of 1,000 m. 

STUDY RESULTS: This project was designed to convert existing seafloor maps 

compiled from high-resolution seismic profiles, side-scan sonar data, and bathymetry 

acquired in 182 OCS lease blocks to MMS-approved GIS format for use in geohazards 

evaluations. Six mapping categories were used: (1) undisturbed seafloor, (2) seafloor 

erosion, (3) hard bottom areas (carbonate banks, bioherms, hardgrounds, and 

outcrops), (4) faults, (5) acoustic wipeout zones, and (6) mass movement features. In 

addition to converting existing maps produced at Coastal Studies Institute through an 

industry consortium, mapping of new 3-D seismic surface amplitude data filled many of 

the gaps in the high-resolution acoustic data sets. The goal was to extend the mapping 

wherever possible to water depths of 1,000 m. All mapped data were converted to 

MMS-GIS compatible products. Past experience has clearly shown that understanding 

the processes that are associated with geohazards and locations of potential “trouble 

spots” on the seafloor saves money and lives. This project produced a set of seafloor 

maps from five mapping areas that can be used for planning man’s activities in the OCS 

region of the northern Gulf of Mexico from the shelf edge to a depth of 1,000 m. 

STUDY PRODUCT(S): Roberts, H.H., J.M. Coleman, and R.H. Peele. 2005. Mapping 

areas of hard bottom and other important bottom types: Outer continental shelf and 

upper continental slope; final report. U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2005-067. 45 

pp. + 6 maps. 
ACCESS NUMBER: 30951-17800 

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