Skip to main content
U.S. flag

An official website of the United States government

GIS Data

USGS is a primary source of geographic information system (GIS) data. Our data and information is presented in spatial and geographic formats, including The National Map, Earth Explorer, GloVIS, LandsatLook, and much more. Explore GIS Data Maps. 

Filter Total Items: 9494

Carolina Trough structure contour maps

Four strong reflection horizons identified on multichannel seismic-reflection profiles of the U.S. continental margin east of the Carolinas have been traced and contoured (maps A-D).  Depths, in kilometers, to the horizons were calculated by the method of Taner and Koehler (1969) using the reflection-time and RMS (root-mean-square) velocities from multichannel velocity analyses.  The contoured hor