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Open-File Report 02–361
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Grid of US Magnetic Anomaly Data
  Disclaimer:  Not all of the United States has digital data.  The grid that was used to generate this image of the United States is available as part of the North American Magnetic Anomaly Map, https://pubs.usgs.gov/sm/mag_map/


Magnetic anomaly data provide a means of “seeing through” nonmagnetic rocks and cover such as vegetation, soil, desert sands, glacial till, man-made features, and water to reveal lithologic variations and structural features such as faults, folds, and dikes. Magnetic anomalies reflect variations in the distribution and type of magnetic minerals, primarily magnetite, in the Earth’s crust.  Magnetic rocks can be mapped from the surface to great depths, depending on their dimensions, shape, magnetic properties, and on the character of the local geothermal gradient.  In many cases, examination of magnetic anomalies provides the most expeditious and cost-effective means to accurately map geologic features in the third dimension (depth) at a range of scales.
 

After pioneering the first airborne magnetic survey in 1944, the U.S. Geological Survey (USGS) has collected piecemeal aeromagnetic data for most of the U.S., including offshore areas on both coasts.  The U.S. Geological Survey's digital and analog archives comprise more than 1,000 surveys, covering approximately 8,000,000 line-km of data, flown at various flight heights and line spacings.  The purpose of this report is to compile and standardize original aeromagnetic survey data (approximately 5,800,000 line-km) and make them available to the public.  The data here are a compilation of the currently available digitally standardized magnetic databases, metadata reports, and images of survey coverage and quality.


Browse through the Digital Data Files via FTP at

ftp://ftpext.usgs.gov/pub/cr/co/denver/musette/pub/NA_MAGNETICS/digital_data/


Choose from one of the following states:

 

Alabama
Florida
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Vermont
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Kentucky
Montana
North Carolina
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Arkansas
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North Dakota
Tennessee
Washington
California
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Ohio
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Colorado
Illinois
Michigan
New Jersey
Oregon
US (Offshore)
Wisconsin
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Indiana
Minnesota
New Mexico
Rhode Island
Utah
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Composite and Merged
Aeromagnetic Data for
Alaska
BROWSE DIGITAL DATA
VIA FTP SITE



For further information about aeromagnetic data holdings at the U.S. Geological Survey, please contact
Pat Hill (pathill@usgs.gov) or Bob Kucks (rkucks@usgs.gov).
 

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This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards. Use of brand names is for descriptive purposes and does not constitute endorsement by the U.S. Geological Survey.
Last modified 01/30/2004.

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