This image is an enlarged, detailed area from the Gulf of Mexico GLORIA sidescan sonar mosaic. The image was co-registered with SeaMARC 1A sidescan sonar data collected during R/V FARNELLA 90-3 cruise.

This image is a 250m version of the composite Gulf of Mexico GLORIA sidescan sonar mosaic.

This image is a 250m version of the composite Gulf of Mexico GLORIA sidescan sonar mosaic.

In the late summer and fall of 1985, the USGS conducted surveys of the Exclusive Economic Zone (EEZ) in the Gulf of Mexico. The collected GLORIA data was processed and digitally mosaicked to produce continuous imagery of the seafloor (EEZ-Scan, 1985). A total of 16 digital mosaics of a 2degree by 2degree (or smaller) area with a 50 meter pixel resolution were completed for the Gulf of Mexico. Those individual mosaics were later combined to produce two overviews (east and west) of the Gulf of Mexico at a 250 meter pixel resolution.

Since 1982 the, U.S. Geological Survey (USGS) has collected a large amount of surficial and shallow subsurface geologic information in the deep parts of the Gulf of Mexico. These data include digital sidescan sonar imagery, digital seismic-reflection data, and descriptions and analyses of piston and gravity cores. The data were collected during several different projects that addressed surficial and shallow subsurface geologic processes. Some of these data sets have already been published, but the growing interest in the occurrence and distribution of gas hydrates in the Gulf of Mexico warrants integrating these existing data and associated interpretations into a GIS to provide regional background information for ongoing and future gas hydrate research.

These data are high-resolution acoustic backscatter measurements of the seafloor offshore of Massachusetts, from Nahant to Gloucester. Approximately 127 km2 of the inner shelf were mapped in the nearshore region between the 10m and 40-m isobath.

In 1999, the U.S. Geological Survey (USGS), in partnership with the South Carolina Sea Grant Consortium, began a study to investigate processes affecting shoreline change along the northern coast of South Carolina, focusing on the Grand Strand region. Previous work along the U.S. Atlantic coast shows that the structure and composition of older geologic strata located seaward of the coast heavily influences the coastal behavior of areas with limited sediment supply, such as the Grand Strand. By defining this geologic framework and identifying the transport pathways and sinks of sediment, geoscientists are developing conceptual models of the present-day physical processes shaping the South Carolina coast. The primary objectives of this research effort are: 1) to provide a regional synthesis of the shallow geologic framework underlying the coastal upland, shoreface and inner continental shelf, and define its role in coastal evolution and modern beach behavior; 2) to identify and model the physical processes affecting coastal ocean circulation and sediment transport, and to define their role in shaping the modern shoreline; and 3) to identify sediment sources and transport pathways; leading to construction of a regional sediment budget.

In 1995, the USGS, in cooperation with the U. S. Army Corps of Engineers, New York District, began a program designed to generate reconnaissance maps of the sea floor offshore of the New York-New Jersey metropolitan area, one of the most populated coastal regions within the United States. The goal of this mapping program is to provide a regional synthesis of the sea-floor environment, including a description of sedimentary environments, sediment texture, sea-floor morphology, geologic history, and the geometry and structure of the Quaternary strata. This mapping effort differs from previous studies of these area by obtaining digital, sidescan-sonar images that cover 100 percent of the sea floor. The sidescan-sonar data were digitally mosaicked to provide a base suitable for use in the geographic information system (GIS) of the New York Bight region.

In 2006 and 2007, the U.S. Geological Survey, in partnership with Louisiana Department of Natural Resources and the University of New Orleans, conducted geologic mapping to characterize the sea floor and shallow subsurface stratigraphy offshore of the Chandeleur Islands in Eastern Louisiana. The mapping was carried out during two cruises on the R/V Acadiana. Data were acquired with the following equipment: an SEA Ltd SwathPlus interferometric sonar (234 kHz), Klein 3000 dual frequency sidescan sonar, and an Edgetech 512i chirp subbottom profiling system. The long-term goal of this mapping effort is to produce high-quality geologic maps and geophysical interpretations that can be utilized to investigate the impact of Hurricane Katrina in 2005 and to identify sand resources within the region.