Airborne electromagnetic and magnetic survey data, southeastern San Joaquin Valley near Cawelo, California, 2016: Processed AEM data

Airborne electromagnetic (AEM) and magnetic survey data were collected during October 2016 over a total distance of 262 line kilometers in the southeastern San Joaquin Valley near Cawelo, California. These data were collected in support of groundwater salinity mapping and hydrogeologic framework development as part of the U.S. Geological Survey California Oil, Gas, and Groundwater program and the California State Water Resources Control Board’s Oil and Gas Regional Monitoring Program. Minimally processed binary AEM data received from SkyTEM ApS 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 dropouts. 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 (powerlines, pipelines, etc...) and magnetic anomalies; impacted data were manually removed. Culled electromagnetic data were spatially averaged using a sounding distance of 1.5 seconds and trapezoidal filter widths of 4 and 6 seconds applied after gate time 1e-5 and 1e-4 seconds (low moment data) and 4 and 6 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.

[
  "010:12"
]

[
  "geospatial"
]