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Time-domain electromagnetic (TEM) surveys were done northwest of the Air Force Research Laboratory (AFRL) at Edwards Air Force Base. TEM surveys were done at 33 locations between May and October 2018 to refine the understanding of the bedrock-alluvial aquifer transition zone downgradient from the AFRL. TEM surveys (also called transient electromagnetic surveys) provide 1D resistivity soundings of the subsurface, which can be related to lithology and hydrogeology. In the TEM method, electrical current is cycled through a transmitter loop (Tx) wire, which in turn produces a primary magnetic field. When the current is abruptly terminated, a secondary magnetic field is induced in the earth, and it moves downward and...
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A suite of geophysical methods was used along the Cedar River in Cedar Rapids, Iowa to support the hydrogeologic characterization of the alluvial aquifer associated with the river and to assess the area for suitability for larger-scale airborne geophysics. The aquifer is comprised of sand and gravel, interbedded with finer sediments, and underlain by carbonate-dominated bedrock. The aquifer is the principal source of municipal drinking water for the City of Cedar Rapids. The raw data provided here includes waterborne continuous resistivity profiling (CRP) and continuous seismic profiling (CSP) data (collected at the same time), electrical resistivity tomography (ERT) profiles, and horizontal-to-vertical spectral...


    map background search result map search result map Geophysical Data Collected in the Cedar River Floodplain, Cedar Rapids, Iowa, 2015-2017 Ground-Based Time-Domain Electromagnetic Data Collected at Edwards Air Force Research Laboratory, Antelope Valley, California, 2018 Geophysical Data Collected in the Cedar River Floodplain, Cedar Rapids, Iowa, 2015-2017