Airborne electromagnetic (AEM) and magnetic survey data were collected during March 2018 along 1,637 line kilometers over the western Hualapai Indian Reservation and surrounding areas. The survey was conducted as part of a study of the groundwater resources of the Truxton basin and Hualapai Plateau. The survey was designed to improve the understanding of the geometry of major hydrostratigraphic contacts of the study area. Deterministic laterally constrained inversion of the processed AEM data (https://www.sciencebase.gov/catalog/item/5d606016e4b01d82ce98558e) was conducted using the AarhusINV code (Auken and others, 2014) implemented in Aarhus Workbench software (Aarhus Geosoftware, Aarhus, Denmark). Inversion parameters were selected by running a series of test models with varying starting model resistivity values, layer discretization, horizontal/lateral constraints, and other inversion parameters. A 32-layer fixed-depth smooth inversion model was developed with layer top depths ranging between 5 and 700 meters and layer thickness increasing with depth Inversions were run with vertical and lateral constraints of values of 4.0 and 1.6, respectively, and a 300 ohm-meter homogenous half-space starting model. Sensor altitude was treated as a free parameter after the 7th iteration. Depth of investigation was calculated with a minimum and maximum depth of 5 and 800 meters. The data provided include inverted resistivity models and plotted depth sections along all flight lines. Digital data are described in the data dictionary, additional details regarding data inversion are described in the metadata processing steps.

Airborne electromagnetic (AEM) and magnetic survey data were collected during March 2018 along 1,637 line kilometers over the western Hualapai Reservation and surrounding areas. The survey was conducted as part of a study of the groundwater resources of the Truxton basin and Hualapai Plateau. The survey was designed to improve our understanding of the geometry the major hydrostratigraphic contacts and regional-scale geologic structures of the study area. Minimally processed binary AEM data received from the contractor were imported into the Aarhus Workbench software (Aarhus Geosoftware, Aarhus, Denmark) and processed. Filters were applied to inclinometer and spatial positioning data to smooth raw data and remove sensor drop outs. Altimeter data were filtered, smoothed, and manually edited to correct false altitudes associated with trees and other obstacles, resulting in processed altitude representative of the distance between the AEM sensor airframe and bare earth. Ground surface elevations were imported from the 1 arc second USGS National Elevation Dataset. Raw electromagnetic data were visually examined for couplings and noise associated with infrastructure and considered in the context of the locations of known or suspected infrastructure (power lines, pipe lines, etc...) and magnetic anomalies; impacted data were manually removed. Additional soundings were culled where induced polarization effects were suspected. Culled electromagnetic data were spatially averaged using a sounding distance of 1.5 seconds and trapezoidal filter widths of 6 and 8 seconds applied after gate time 1e-5 and 1e-4 seconds (low moment data) and 6 and 8 seconds applied after 1e-4 and 1e-3 seconds (high moment data). Low-signal data were removed from the averaged data through a combination of filters and manual culling. The data provided include fully processed electromagnetic data produced from minimally processed contractor-delivered data, also provided with this data release. The digital data are described in the data dictionary, additional details regarding processing steps are described in the metadata.

Aeromagnetic data were collected along flight lines by instruments in an aircraft that recorded magnetic-field values and locations. This dataset presents latitude, longitude, altitude, and magnetic-field values.

Aeromagnetic data were collected along flight lines by instruments in an aircraft that recorded magnetic-field values and locations. This dataset presents latitude, longitude, altitude, and magnetic-field values.

Aeromagnetic data were collected along flight lines by instruments in an aircraft that recorded magnetic-field values and locations. This dataset presents latitude, longitude, altitude, and magnetic-field values.

On September 25, 1998, SIAL Geosciences Inc. (SIAL) was awarded Department of Interior, contract 98CRCN1018, by the U.S. Geological Survey. This contract required SIAL to carry out a high-sensitivity magnetic and electromagnetic helicopter survey over one block located in the Eureka Graben Area. The primary goal of this project was to provide digitally recorded and processed magnetic and electromagnetic data in order to evaluate geologic and hydrologic resources of the Eureka Graben Area. The base of on-site field operations was installed at Silverton, Colorado. The survey was carried out by SIAL between May 27th and June 9th, 1999. This report, describing the parameters, data acquisition and processing procedures, was delivered at the end of August, 1999. This metadata file describes the flight line data and attributes, as well as gridded products generated from the flight line data that were delivered to the USGS by SIAL Geosciences Inc.

Aeromagnetic data were collected along flight lines by instruments in an aircraft that recorded magnetic-field values and locations. This dataset presents latitude, longitude, altitude, and magnetic-field values.

This data release provides digital flight line data for a high-resolution airborne magnetic and radiometric survey over the Sierra Madre-Elkhead Mountains-Medicine Bow Mountains region of southern Wyoming and northern Colorado. The airborne survey was funded by the Earth Mapping Resources Initiative. The survey was designed to meet complementary needs related to geologic mapping and characterization of mineral resource potential. A total of about 72,000 line km of magnetic and radiometric data were acquired over an irregular-shaped area of about 13,000 km2. Data were collected from a helicopter flown at a nominal terrain clearance of 100 meters (m) above topography along N-S flight lines spaced at 200 m intervals. Tie lines were flown in an E-W direction every 2000 m. Data were collected by New-Sense Geophysics Ltd. and Merrick-Surdex Joint Venture, LLP, under contract to the USGS using a helicopter with a magnetometer mounted in a stinger and a fully calibrated gamma-ray spectrometer. The survey operated out of airports in Laramie (WY), Saratoga (WY), Steamboat Springs (CO), Craig (CO), Walden (CO), and Loveland (CO) from September of 2023 to September of 2024. Files that are available in this publication include flight line data for the magnetic survey, flight line data for the radiometric survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. A zip file is provided that contains the contractor's deliverable products that includes Geosoft databases and grids for the magnetic and radiometric survey and the report describing the survey and data reduction.

Aeromagnetic data were collected along flight lines by instruments in an aircraft that recorded magnetic-field values and locations. This dataset presents latitude, longitude, altitude, and magnetic-field values.