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  "name" : "Sediment Thickness", 
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  "description" : "In 1999, the 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.\n\nThis data set contains an isopach surface depicting the thickness of Holocene surficial sediment within the inner shelf of Long Bay, offshore of the South Carolina Grand Strand. Chirp seismic data collected with Benthos SIS-1000 and Edgetech SB-512 acquisition systems were processed using SIOSEIS (Scripps Institute of Oceanography) and Seismic Unix (Colorado School of Mines) to produce segy files and jpg images of the profiles. Data were then imported into Landmark SeisWorks, a digital seismic interpretation package, where the sea floor and underlying transgressive surface (trans_grd) were interpreted and digitized. The isopach between these horizons was exported at every 50th shot as xyz points, and imported to ArcGIS for interpolation into a 10-m raster grid. Each Chirp system has a maximum vertical resolution of ~ 50 cm, so only values greater than 50 cm were used to produce the isopach grid. This does not mean that all no-data values within the grid are representative of no surficial sediment along the inner shelf, but does indicate that these areas likely contain accumulations of less than 50 cm.\n", 
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