Study to estimate the 3-D distribution of permafrost, to evaluate the effectiveness of these methods at mapping permafrost geometry, and to better define the physical properties of the subsurface in discontinuous permafrost areas.

Airborne electromagnetic and magnetic survey data were collected during 2016 along 4,212 line-kilometers over this area. The survey was flown with a nominal line spacing of 450 meters or less, and mean flight height about 48 m providing depth of investigation about 500m. Data are provided in CSV format, flight lines in shapefile format.

Releases airborne survey data, resistivity cross-sections and depth slices derived from data inversion. Resulting resistivity models confirm geologic framework, constrain hydrostratigraphy and depth to basement, and reveal fault and fold distribution.

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.

Digital flight-line aeromagnetic and aeroradiometric survey data over of the southeast Mojave Desert, parts of California and Nevada. Data files are provided in CSV as well as Geosoft binary database and grid exchange format (GXF).

Digital flight line data for a high-resolution airborne magnetic and radiometric survey of this area. A total of 40,139-line km of magnetic and radiometric data were acquired over an irregular-shaped area of 9140 sq km. Data are provided in CSV, GeoTIFF, and Geosoft formats.

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.

Digital flight line data from a high-resolution magnetic survey over this area. The survey was flown in 2008 by Aeroquest under contract to Kennecott Eagle Minerals Company using a fixed-wing aircraft with a magnetometer mounted in a tail stinger. The USGS has obtained this 66,074 line km subset of the survey dataset for public release. Data are provided in Geosoft database and CSV formats.

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.

Flight-line data and gravity grids with documentation.

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.

Measurements of the gravitational field vary slightly from place to place due to the composition and structure of Earth's crust. Includes the isostatic and Bouguer anomalies for the conterminous US.

The objective of the survey was to improve the understanding of the relationship between surface water and groundwater systems critical to developing management programs for water resources.

Detailed airborne gravity gradiometry, magnetic, and radiometric survey data for this area flown with flight-line spacing of 100 and 200 m, nominal flight-line elevation above ground of 70 m, for about 1,814 line-kilometers. Data are provided in CSV and Geosoft database (.gdb) format. Gravity and hillshade are in GXF grids.

Radiometric (uranium, thorium, potassium content and gamma-ray intensity) and related data were digitized from radiometric and survey route location maps of western Afghanistan previously published by others in 1976.

The report presents new maps from data collected in 2007 and the processing steps applied to that data. The maps are being used for natural resource development and to prioritize study areas of mineral distribution to assist with economic revitalization.

Flight-line databases and derived grids from aeroradiometric surveys across the US carried out during the 1970s