DC resistivity soundings were made to map subsurface lithologic, structural and hydrologic features important in controlling possible ground water contamination from mining activities and for design of remediation efforts.

Airborne geophysical data and a summary of the hydrologic application.

Grids, images, and flight-line paths for magnetic and resistivity surveys

Grids, line data, and imagery derived from them covering the small study area.

Electrical resistivity depicted in georeferenced grids and maps, representing different approximate depths of investigation for each area. The range of subsurface investigation is comparable to the depth of shallow aquifers.

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.

Geophysical surveys to map shallow hydrogeologic features of the southwestern part of the Sand Hills that contain a mix of fresh to saline lakes.

Flight line data, grids, and inversions for these surveys are intended to help understand shallow groundwater and develop groundwater resource plans for the aquifer.

The objective of the contracted survey was to improve the understanding of the relation between surface water and groundwater systems critical to developing groundwater models used in management programs for water resources.

Electromagnetic, resistivity, and magnetic surveys used to determine the extent of contamination in an abandoned mine area.

Flight-line data, flight-line and aeromagnetic anomaly map images

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 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.

Survey parameters, data acquisition and processing procedures, and products of a 1999 airborne geophysical survey of this area. Data provided in GXF format and binary formats.

High resolution aeromagnetic survey used to infer the locations of igneous rock bodies in the area, which are provided in GIS data files

Data sets include drill-hole from core and geophysical logs, surface geology and elevation, and helicopter electromagnetic survey data. The model may be explored and .jpg or .tiff images or using specialized software provided.

Airborne electromagnetic and magnetic survey data were collected in 2017 along 347 line kilometers. Includes processed AEM and magnetic data and inverted resistivity depth sections. Data are provided in CSV format.

Airborne electromagnetic (AEM) and magnetic survey data collected in 2015 along 769 line-kilometers including raw and processed AEM and magnetic data, processed AEM resistivity-depth inversions. Data are provided in CSV format.

Spatial footprints with scientific and operational characteristics of airborne electromagnetic surveys conducted by or for the USGS.

Shallow subsurface electrical conductivity mapped at selected U.S. Fish and Wildlife Service managed lands in northeast Montana and northwest North Dakota in the winters of 2017 and 2018. Data are provided in CSV format, locations are provided in shapefile format.

<h1>Introduction</h1>The San Juan-Silverton caldera complex located near Silverton, Colorado, in the Southern Rocky Mountains volcanic field is an ideal natural laboratory for furthering the understanding of shallow-to-deep volcanic-related mineral system

Airborne electromagnetic and magnetic survey data were collected during 2019 along 1,467 line-kilometers in this area. The survey was flown at a mean flight height of 140 meters (m) above terrain and line spacings ranging from 150 m to 600 m. Data are provided in CSV and shapefile formats.

Airborne electromagnetic and magnetic survey data collected during April and May 2019 along 1,467 line-kilometers in this area. Data are provided in netCDF format.

Airborne electromagnetic, magnetic, and radiometric data were acquired in 2018 along 2,364 line-kilometers in this area at anominal sensor flight height of 30 m above terrain with 250 to 1,000-meter spaced flight lines. Data are provided in GXF grid, CSV, and GeoTiff formats.

Compilation of airborne geophysical surveys (magnetic, radiometric, and electromagnetic) with links, for each survey to the data, metadata, and preview images. Includes a measure of quality indicating which surveys are likely most useful for investigations of subsurface mineral deposits. Data are provided in Esri file geodatabase, shapefile, and CSV formats.