Filters: Tags: Electromagnetic induction (X)
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From October 2016 to July 2018, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers and Maine Department of Transportation, collected surface, marine and borehole geophysical surveys to characterize the subsurface materials on land and under the water at a former mine facility in Brooksville, Maine. Three water-based geophysical methods were used to evaluate the geometry and composition of subsurface materials. Continuous seismic profiling (CSP) methods provide the depth to water bottom, and, when sufficient signal penetration can be achieved, delineate the depth to bedrock and subbottom materials. Continuous resistivity profiling (CRP) and frequency domain electromagnetics (FDEM) methods...
Surface electrical resistivity tomography (ERT), electromagnetic induction (EMI), and self-potential (SP) data were acquired March 9 - 20, 2018 by the U.S. Geological Survey, in collaboration with the U.S. Army Corps of Engineers, at the Jim Woodruff Lock and Dam near Chattahoochee, Florida. Eleven ERT profiles were acquired along the right (west) abutment, and immediately downstream, of the concrete, fixed-crest spillway located west of the lock to map geologic structure at depths up to 50 meters (m) using the Advanced Geosciences, Inc. SuperSting R8 resistivity meter. This data release includes the raw and processed resistivity data as well as inverted resistivity models. All are provided as digital data, and...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Apalachicola River,
Chattahoochee,
Chattahoochee River,
Decatur County,
ERT surveying,
In October 2016 and May 2017 frequency domain electromagnetic (FDEM) methods were used to image the electrical conductivity of the shallow subsurface. Electrical conductivity can be caused by changes in the soil, overburden, saturation, and water quality. Two multi-frequency tools were used at the site. One of the tools has a 1.6-m long antenna that was used in the vertical-dipole mode to collect data in stepped-frequency mode at seven user-selected frequencies ranging from 1530 to 47,970 Hz. The second tool has an antenna that is 2.1 m long, and it was used in vertical dipole mode with five stepped frequencies ranging from 90 to 24,000 Hz. In general, the lower frequencies penetrate to deeper depths, but the data...
Surface electrical resistivity tomography (ERT), electromagnetic induction (EMI), and self-potential (SP) data were acquired March 9 - 20, 2018 by the U.S. Geological Survey, in collaboration with the U.S. Army Corps of Engineers, at the Jim Woodruff Lock and Dam near Chattahoochee, Florida. Self-potential (SP) data were acquired at 384 unique stations with Borin Stelth 3 copper-copper sulfate porous-pot electrodes and Keysight U1253B high-impedance multimeter to identify variations in subsurface hydrologic flow. This data release includes the raw and processed self-potential data. They are provided as digital data, and data fields are defined in the data dictionary. Jim Woodruff Lock and Dam is located...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Apalachicola River,
Chattahoochee,
Chattahoochee River,
Decatur County,
ERT surveying,
In October 2016 and May 2017 frequency domain electromagnetic (FDEM) methods were used to image the electrical conductivity of the shallow subsurface. Electrical conductivity can be caused by changes in the soil, overburden, saturation, and water quality. Two multi-frequency tools were used at the site. One of the tools has a 1.6-m long antenna that was used in the vertical-dipole mode to collect data in stepped-frequency mode at seven user-selected frequencies ranging from 1530 to 47,970 Hz. The second tool has an antenna that is 2.1 m long, and it was used in vertical dipole mode with five stepped frequencies ranging from 90 to 24,000 Hz. In general, the lower frequencies penetrate to deeper depths, but the data...
The U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force Civil Engineer Center (USAF/CEC), conducted a pilot study at Malmstrom Air Force Base (MAFB) to evaluate the utility of two non-invasive geophysical techniques for detecting hydrocarbons in subsurface materials. Electrical resistivity tomography (ERT) and electromagnetic induction (EMI) surveys were completed August 28–29, 2023, along 7 transects overtop contaminated and uncontaminated sites for comparison. Additionally, the USGS completed ultraviolet optical scanning tool (UVOST) soundings and collected soil samples from temporary boreholes to validate geophysical survey results. A total of 11 UVOST soundings and 7 boreholes were completed...
Categories: Data;
Tags: Cascade County,
Malmstrom Air Force Base,
Montana,
Montana,
USGS Science Data Catalog (SDC),
Presented is a list of voltages (electric potential differences) measured during magnetic storms on grounded long lines in the United States and Canada between 1891 and 1940. The sources for the list are published papers, technical documents, and newspapers. Each entry consists of the maximum voltage measured for each storm on a specified line connecting two ground points, nominally, between A "and" B. However, if a specific polarity is available, for example, the positive voltage from point A to point B, then the maximum voltage for the indicated polarity is listed, that is, positive A "to" B; conversely, for the opposite polarity, that is, from point B to point A, then the maximum voltage for the indicated polarity...
Categories: Data;
Tags: Canada,
Earth surface,
Electromagnetic induction,
Geoelectric field,
Geomagnetic field,
Surface electrical resistivity tomography (ERT), electromagnetic induction (EMI), and self-potential (SP) data were acquired March 9 - 20, 2018 by the U.S. Geological Survey, in collaboration with the U.S. Army Corps of Engineers, at the Jim Woodruff Lock and Dam near Chattahoochee, Florida. Frequency-domain electromagnetic induction data were acquired along approximately 9 line-kilometers with the Geophex GEM-2 system to map variations in structure up to about 10 m in depth. This data release includes the raw and processed frequency-dependent in-phase and quadrature data. They are provided as digital data, and data fields are defined in the data dictionary. Jim Woodruff Lock and Dam is located on the Apalachicola...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Apalachicola River,
Chattahoochee,
Chattahoochee River,
Decatur County,
ERT surveying,
Surface electrical resistivity tomography (ERT), electromagnetic induction (EMI), and self-potential (SP) data were acquired March 9 - 20, 2018 by the U.S. Geological Survey, in collaboration with the U.S. Army Corps of Engineers, at the Jim Woodruff Lock and Dam near Chattahoochee, Florida. Eleven ERT profiles were acquired along the right (west) abutment, and immediately downstream, of the concrete, fixed-crest spillway located west of the lock to map geologic structure at depths up to 50 meters (m) using the Advanced Geosciences, Inc. SuperSting R8 resistivity meter. Frequency-domain electromagnetic induction data were acquired along approximately 9 line-kilometers with the Geophex GEM-2 system to map variations...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Apalachicola River,
Chattahoochee,
Chattahoochee River,
Decatur County,
ERT surveying,
This data release contains borehole geophysical data collected within and near Ellsworth Air Force Base, South Dakota, from September 2020 to August 2021. The data accompanies a USGS scientific investigations map from Medler and others (2022). The U.S. Geological Survey, in cooperation with the U.S. Air Force Civil Engineer Center, collected borehole geophysical data and performed simple aquifer tests to estimate the thickness and hydraulic properties of surficial deposits. The purpose of data collection was to create generalized contour maps of Pierre Shale elevation and surficial deposit thickness within and near Ellsworth Air Force Base (study area). Natural gamma and electromagnetic induction (EMI) data were...
Categories: Data;
Tags: Ellsworth Air Force Base,
Geophysics,
Hydrology,
Meade County,
Pennington County,
Electromagnetic induction (EMI) instruments provide rapid, noninvasive, and spatially dense data for characterization of soil and groundwater properties. Data from multi-frequency EMI tools can be inverted to provide quantitative electrical conductivity estimates as a function of depth. In this study, multi-frequency EMI data collected across an abandoned uranium mill site near Naturita, Colorado, USA, are inverted to produce vertical distribution of electrical conductivity (EC) across the site. The relation between measured apparent electrical conductivity (ECa) and hydraulic conductivity (K) is weak (correlation coefficient of 0.20), whereas the correlation between the depth dependent EC obtained from the inversions,...
Categories: Publication;
Types: Citation;
Tags: Electrical conductivity,
Electromagnetic induction,
Hydraulic conductivity,
Petrophysical relationships,
inverse modeling
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