U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2004–3082

September 2004

The USGS Role in Mapping the Nation’s Submerged Lands

Printed on recycled paper

The Nation’s Submerged Lands

The seabed provides habitat for a diverse 

marine life having commercial, recreational, 

and intrinsic value. The habitat value of the 

seabed is largely a function of the geological 

structure and related geological, biological, 

oceanologic, and geochemical processes. Of 

equal importance, the nation’s submerged lands 

contain energy and mineral resources and are 

utilized for the siting of offshore infrastructure 

and waste disposal. Seabed character and processes influence the safety and viability of offshore operations. Seabed and subseabed characterization is a prerequisite for the assessment, 

protection, and utilization of both living and 

non-living marine resources (fig. 1). A comprehensive program to characterize and understand 

the nation’s submerged lands requires scientific 

expertise in the fields of geology, biology, 

hydrography, and oceanography.

USGS Leadership in Geologic Mapping

The U.S. Geological Survey (USGS) has 

long experience as the Federal agency charged 

with conducting geologic research and mapping in both coastal and offshore regions. The 

USGS Coastal and Marine Geology Program 

(CMGP) leads the nation in expertise related 

to characterization of seabed and subseabed 

geology, geological processes, seabed 

dynamics, and (in collaboration with the 

National Oceanic and Atmospheric Administration (NOAA) and international partners) 

habitat geoscience. Numerous USGS studies 

show that sea-floor geology and processes 

determine the character and distribution of 

biological habitats, control coastal evolution, influence the coastal response to storm 

events and human alterations, and determine 

the occurrence and concentration of natural 

resources.

Regional and Topical Studies

The CMGP uses research and mapping 

expertise to conduct regional and topical 

studies that address issues on the nation’s 

submerged lands related to hazards, natural 

resources, environmental impacts, environmental change, and engineering projects. The 

CMGP collaborates with national and international agencies to develop new approaches 

for collecting and interpreting seabed imagery, 

mapping shallow stratigraphy, and gathering 

related data relevant to habitat determination, 

resource assessments, and the understanding 

of vulnerability and change.

Hazards—Studies address the impacts 

of earthquakes, tsunamis, and submarine and 

coastal landslides, as well as coastal change 

caused by erosion, storms, sea-level rise, and 

land subsidence, and are the basis for national 

assessments of vulnerability and change.

Figure 1. Interpretive map of the southeastern part of Stellwagen Bank and adjacent small banks, about 80 kilometers east of Boston, Mass. Map shows shaded-relief

imagery of the seabed, detailed topography (1-meter contours) of the most rugged areas, and the distribution of seabed habitats that range from smooth to rough and

from muddy (purple, blue) to sandy (green, yellow) to gravelly (gray and reddish brown). Map area is 220 square kilometers; water depths range from 35 meters in the

west to 180 meters in the east. Photographs show habitats supporting different kinds of marine life. A, Storm-generated coarse sand ripples with sand dollars (6 centimeters diameter); depth 39 meters. B, Boulders encrusted with sponges, sea stars, brachiopods, and tunicates; small boulder is 30 centimeters wide; depth 89 meters. 

C, Smooth, muddy sand seabed with fish or crab burrows; depth 137 meters.
Natural Resources—Studies of the occurrence and distribution of sand and gravel, 

other mineral resources, methane gas hydrate, 

and ground water lead to assessments of 

resource potential and of impacts of resource 

utilization.

Environment—Studies of seabed 

environments provide the geological basis for 

understanding physical processes in healthy 

and declining lacustrine, wetland, estuarine, 

marine, benthic, and coral ecosystems. Areas 

of habitat geoscience research include the 

following:

• Development and application of analytical methods and “ground-truth” 

approaches required to interpret digital 

sea-floor imagery

• Development of geology-based methods 

to classify and inventory seabed types 

and habitats; documentation of how species distributions are influenced by the 

geological character and processes that 

affect habitats

• Investigation of geochemical cycling 

of contaminants impacting ecosystem 

and human health; development of 

techniques to assess and model coastal 

ground-water resources and the influence 

of ground water on submerged habitats

• Development of physical, geochemical, 

and coupled physical-ecological models 

to predict (1) ocean circulation; (2) sediment movement; (3) effects of currents 

on seabed morphology, materials, and 

organisms; (4) drift patterns of plankton 

and of eggs and larvae of fishery species; and (5) transport and ecosystem 

impacts of contaminants and ground 

water.

Comprehensive Seabed Mapping

The CMGP provides expertise essential for 

the development of a comprehensive seabed 

mapping program by (1) pursuing the research 

topics discussed above, (2) developing new 

survey techniques, (3) providing geological 

analyses of seabed imagery and subseabed 

data, and (4) producing interpretive maps that 

show the distribution of sediments, ground 

water, contaminants, and seabed habitats, 

as well as sediment transport processes and 

the structure and depositional history of the 

seabed (fig. 2).

CMGP can support enhanced mapping 

programs by developing new approaches to 

mapping, by testing new concepts for image 

and data interpretation, and by coordinating 

prioritized mapping activities to meet longterm research and immediate management 

goals. Effective mapping programs will require 

USGS expertise and partnerships with government, industry, and academia in order to meet 

the objectives of management and regulatory 

agencies and to ensure that the breadth of 

research capabilities reflects the diverse applications that are required of seabed maps.

For more information, please contact:

Bill Schwab

U.S. Geological Survey

Woods Hole Science Center

384 Woods Hole Road

Woods Hole, MA 02543-1598

Telephone: (508) 457-2211

E-mail: bschwab@usgs.gov

John Haines

U.S. Geological Survey

Mail Stop 915B

National Center

Reston, VA 20192-0002

Telephone: (703) 648-6422

E-mail: jhaines@usgs.gov

Figure 2. Seabed map, three-dimensional sidescan-sonar perspective images, and subbottom profile of the sea floor off Myrtle Beach, S.C. These images were

produced aboard a research vessel as part of an ongoing investigation of coastal erosion hazards. Top right, The color image shows bathymetry. The black and white 

image above it combines bathymetry and seabed backscatter (the intensity of sound reflected from the sea floor); gray tones represent seabed types and range from

hard (light gray) to soft (dark gray). Bottom, Subbottom profile A-A’ illustrates the recent history of the sea floor and shows the accumulation of a young sand deposit 

over older, harder, folded beds.