Aeromagnetic survey data giving the calculated magnetic anomaly. Data are provided in CSV format.

Digital files and descriptions of airborne and ground collected magnetic data in Afghanistan

Flight-line data from the aeromagnetic survey

Airborne electromagnetic (AEM) and magnetic survey data, a total of 3065 line-kilometers, collected during October 2001 with line spacing 400m and nominal altitude of 30m. Includes raw and processed AEM data and magnetic data, in CSV format.

Airborne electromagnetic and magnetic survey data were collected in 2014 in this area. The survey was flown at a nominal flight height of 30 m above terrain, line spacing of 200 m with a smaller area at 100 m. Includes raw and processed AEM data and spatially-constrained inverted resistivity depth sections, and unprocessed and processed magnetic data that has been drift corrected, leveled, and draped to terrain. Data are provided in CSV format.

Digital flight line data for a high resolution horizontal magnetic gradient and radiometric survey over this area. Flight line spacing was 300 m, mean terrain clearance was 140 m. Includes flight line data for the magnetic gradient survey, flight line data for the radiometric survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. Data are provided in CSV format, flight lines are provided in shapefile format.

Digital flight line data for a high-resolution magnetic survey with line spacing 150 meters and nominal terrain clearance 80 meters over most of the study area. Data are provided as Geosoft databases and grids. Data over two small areas (less than 1 sq km combined) were redacted because those areas include multiple tracts of Native American lands.

Airborne magnetic survey data collected from this area to better understand the lithology and structure of exposed and concealed Precambrian rocks in support of mineral resource investigations. Results are provided in Geosoft database, grid exchange format, GeoTiff, and CSV.

Airborne magnetic survey data collected from this area to understand Precambrian rocks concealed under Paleozoic sedimentary rocks in northeast Iowa. Data are provided in GXF grid and CSV formats. Flight lines are provided in shapefile format.

Report discussing application of specialized instrumentation for detecting unexploded ordnance.

Grids and flight-line data for three airborne geophysical surveys

Report with gravity station data in a spreadsheet

Field measurements: 548 gravity and 6484 magnetic anomaly locations, data in fixed-format text files.

Gravity station data and hand-held magnetometer measurements with analysis and description of methodology

Aerial, truck-towed, and hand-held magnetometer measurements, gravity station data, and sample density and magnetic susceptibility measures

Results of a detailed ground magnetic survey

Hand-held magnetometer and sample magnetic susceptibility measurements used to help interpret complex patterns in the magnetic anomaly of this area.

High resolution magnetic and gravity gradient data were collected in this area centered on the Pea Ridge iron oxide-apatite rare-earth element deposit. Flight lines spacing was 400 m, nominal flight height above terrain was 80 m. Includes flight line data for the gravity gradiometry survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. Data are provided in CSV format.

Survey to map concealed faults that may be related to geothermal resources, such as hot springs; data given are surface locations of faults interpreted from the survey.

Explanation of the Earth's magnetic field and how USGS measures it. Defines magnetic anomaly, induced and remanent magnetism in rocks, and describes magnetic anomaly maps.

Magnetic and gravity investigations were undertaken in Mono Lake to study regional crustal structures and to aid in understanding the geologic framework, in particular regarding potential geothermal resources and volcanic hazards throughout Mono Basin.

Database includes new helicopter aeromagnetic data, point locations of the local maximum horizontal gradient derived from the aeromagnetic data, and physical property data.

Magnetic susceptibility measurements with statistical analysis

In-place rock magnetic susceptibility measurements for 746 sites are reported in a database. These data, collected from 1991 through 2012, are intended to help improve geophysical modeling of the Earth’s crust in the Western United States.

Flight line data for an airborne magnetic survey with nominal sensor height of 60m above terrain, flight-line data for a gravity gradiometry survey, with a report containing instrument and procedure details. Data are provided in CSV format.

Report with excel tables showing principal facts (gravity observation data) and ground magnetic data.

Three contractor reports and data files for an airborne electromagnetic survey describing data aquisition and processing. Processed geophysical data were inverted to produce resistivity depth sections along flight lines. Results are described herein.

Regional grid files and 3D voxel models were used to study crustal architecture. Includes grid files consist of surface grids used in the inversions, and calculated geophysical data grids produced by the inversions. Data are provided in GOCAD voxel and GXF grid formats.

Surveys originally carried out by Soviet geophysicists from 1972 through 1974 were digitized. Georeferencing was problematic as were some of the measured characteristics; we explain what we did and how we have understood these data.

Existing and new gravity station data and magnetometer measurements used to infer geologic structure of this area

Geophysical interpretation of the southern Española basin for the purpose of understanding the hydrogeologic framework including shallow faults, igneous units, and basement rocks

Magnetotelluric (MT) sounding data collected in 2005 along an east-west profile in this area, to know whether major mining districts in the Northern Nevada Gold Province are underlain by rocks of the Archean Wyoming craton, which are known to contain orogenic gold deposits, or by accreted rocks of the Paleoproterozoic Mojave province.

Magnetotelluric sounding data collected in 2008 in this area to help USGS understand concealed mineral resources.