Filters: Tags: electrical resistivity tomography (X)
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Alaska permafrost characterization: Borehole Nuclear Magnetic Resonance (NMR) data collected in 2021
Geophysical measurements were collected by the U.S. Geological Survey (USGS) at five sites in Interior Alaska in September 2021 for the purposes of imaging permafrost structure and quantifying variations in subsurface moisture content in relation to thaw features. Borehole nuclear magnetic resonance (NMR) data were collected at two sites in order to determine liquid water content at depth in shallow boreholes. NMR data were collected in a 2.25 m-deep borehole at the North Star golf course adjacent to one of the ERT profiles, and in another two 1.625 m-deep boreholes adjacent to Big Trail Lake where previous NMR measurements were made in 2019 and 2020.
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Active layer thickness,
Alaska,
Bonanza Creek,
Borehole nuclear magnetic resonance,
Disturbance,
A suite of geophysical methods was used along the Des Moines River, Beaver Creek, and in the Des Moines River floodplain in Des Moines, Iowa to support the hydrogeologic characterization of the alluvial aquifer associated with the river. The aquifer consists of sands and gravels underlain by weathered shale bedrock. Groundwater from the aquifer along with surface water sources are used for municipal drinking water for the City of Des Moines and surrounding communities. The raw data provided in this data release are minimally processed to filter out erroneous measurements. Data provided in this data release includes continuous resistivity profiling (CRP) and continuous seismic profiling (CSP) that were collected...
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site,surveys were performed...
Electrical resistivity tomography (ERT) surveys were collected in summer 2018 to support hydrogeologic characterization of the alluvial aquifer. For this investigation, 7 surveys were conducted with ERT methods. At each site three surveys were collected, including dipole-dipole (DD), Wenner-Schlumberger (WS), and Inverse Schlumberger (SI )configurations. For each survey a total of 56 electrodes spaced 5-meters (m) apart were used. During the ERT measurement, current is injected through two current electrodes and voltage is measured sequentially across multiple pairs of potential electrodes, which is used to determine the apparent resistivity of the subsurface. Results were combined into a merged dataset. ERT surveys...
Categories: Data;
Tags: Aquifer Characterization,
Des Moines,
Electrical Resistivity Tomography,
Geophysics,
Hydrogeology,
Electrical resistivity tomography (ERT) measurements were collected by the U.S. Geological Survey (USGS) at two sites in Interior Alaska in September 2019 for the purposes of imaging permafrost structure and quantifying variations in subsurface moisture content in relation to thaw features. First, ERT data were collected at Big Trail Lake, a thermokarst lake outside of Fairbanks, Alaska, to quantify permafrost characteristics beneath the lake and across its shorelines. Three 222 m ERT survey lines were collected perpendicular to the North, East, and South shorelines, and two 110 m lines were collected parallel to the southeast and northeast shorelines. Models of electrical resistivity produced from these data revealed...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Active layer thickness,
Alaska,
Big Trail Lake,
Bonanza Creek Experimental Forest,
Disturbance,
The Air Force Research Laboratory (AFRL) is about 7 kilometers southwest of Boron, California, and covers 320 square kilometers of Edwards Air Force Base. The AFRL consists of 12 facilities for testing full-size rocket engines, engine components, and liquid and solid propellants. The historical release of contaminants from rocket test stands, evaporation ponds, burn pits, catch basins, and leaking waste-collection tanks has contaminated groundwater in the AFRL. Groundwater aquifers near the AFRL are mostly restricted to fractured granitic bedrock, but previous studies indicate that groundwater and associated contaminants have moved into alluvium to the north and northwest. The U.S. Geological Survey (USGS) and the...
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...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Shapefile;
Tags: Antelope-Fremont Valleys,
Boron,
California,
Edwards Air Force Base,
Kern County,
Electrical resistivity tomography (ERT) surveys were done northwest of the Air Force Research Laboratory (AFRL) at Edwards Air Force Base. ERT surveys were done at four locations in May through June of 2018 to refine the understanding of the bedrock-alluvial aquifer transition zone downgradient from the AFRL. The ERT technique injects direct-current electricity with known voltage and current into the earth using a series of electrodes and measures the resulting resistivity. This technique is generally limited to investigations of aquifer properties less than 100 meters below land surface. Data from other geophysical techniques co-located with the ERT data, including time-domain electromagnetics and horizontal-to-vertical...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Shapefile;
Tags: Antelope-Fremont Valleys,
Boron,
California,
California Water Science Center,
Edwards Air Force Base,
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site,surveys were performed...
Surface electrical resistivity tomography, magnetic, and gravity surveys were conducted in July 2017 in the greater East River Watershed near Crested Butte Colorado with a focused effort in Redwell Basin as part of a broader study of the role of bedrock groundwater in the hydrogeology of mineralized mountain watersheds. Approximately ten kilometers of total field magnetics data were acquired on July 29, 2017 with a Geometrics G-858 cesium vapor magnetometer that detects changes in deep (tens of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations. This data release includes the raw and processed magnetics data. They are provided as digital data, and data...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Brush Creek,
Colorado,
Crested Butte,
East River,
GGGSC,
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,
The hydrogeology of the Cannon Air Force Base (AFB) in Curry County, is being investigated to better understand the mechanics of groundwater flow in the area, including the identification of preferential groundwater flow paths. Mapping the top of the Dockum Group was done to help identify potential paleochannels that may have eroded the surface of the Dockum Group and subsequently filled in with coarse-grained sediments of the overlying Ogallala Formation. The Dockum Group is composed of sandstone, siltstone, mudstone, and shale that were originally deposited in fluvial and lacustrine environments (McGowen and others, 1979). The upper part of the Dockum Group is a thick layer of red clay referred to locally as the...
Along-shore surface-based 2D electrical resistivity tomography (ERT) surveys were collected in the nearshore region of Makua, Kauai.
The Santa Clara River Lakes, located along the San Andreas fault 19 miles northwest of Palmdale, California, were placed on the state’s “303(d) List” or “Impaired Water List” in 1996 for eutrophic conditions, high pH, and low dissolved oxygen. In 2016, the state adopted a Total Maximum Daily Load (TMDL) for nutrients (nitrogen and phosphorus) in the Santa Clara River Lakes. This study focuses on the largest of the three lakes, Lake Elizabeth, which is surrounded by the unincorporated town of Elizabeth Lake, CA. The local community uses on-site wastewater treatment systems instead of a centralized sewer system, resulting in potential contamination of groundwater. In response to concerns over the quality of water...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
California Water Science Center,
Electrical Resistivity Tomography,
Elizabeth Lake,
Geophysics,
Surface electrical resistivity tomography (ERT) data were collected in September of 2018 near Ollalie North springs in the upper McKenzie River watershed of west-central Oregon. ERT data were acquired along a single transect on the north bank of Ollalie Creek using a combination of inverse Schlumberger, dipole-dipole, and Wenner arrays. These data were collected to contribute high-resolution subsurface information about the geologic structure and distribution of groundwater near high-discharge springs in the Oregon High Cascades. This data release includes the raw resistivity data, inverted resistivity models, and locational information.
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Shapefile;
Tags: GGGSC,
Geology, Geophysics, and Geochemistry Science Center,
Linn County,
McKenzie River,
Ollalie Creek,
Surface electrical resistivity tomography (ERT), time-domain electromagnetics (TEM), nuclear magnetic resonance (NMR), magnetics, and gravity data were acquired in 2016, 2017 and 2018 in the greater East River Watershed near Crested Butte Colorado with a focused effort in Redwell Basin. Five ERT profiles were acquired within Redwell Basin and Brush Creek to map geologic structure at depths up to 40 meters, depending on the subsurface resistivity, using the Advanced Geosciences, Inc. SuperSting R8 resistivity meter. Approximately ten kilometers of total field magnetics data were acquired with a Geometrics G-858 cesium vapor magnetometer that detects changes in deep (tens of meters to kilometers) geologic structure...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Brush Creek,
Colorado,
Crested Butte,
East River,
Environmental Health,
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,
Surface electrical resistivity tomography, magnetic, and gravity surveys were conducted in July 2017 in the greater East River Watershed near Crested Butte Colorado with a focused effort in Redwell Basin as part of a broader study of the role of bedrock groundwater in the hydrogeology of mineralized mountain watersheds. Ten gravity stations were acquired with a LaCoste and Romberg G-model relative gravimeter to map density variations. This data release includes principal facts for the gravity stations provided as digital data. Data fields are defined in the data dictionary.
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Shapefile;
Tags: Brush Creek,
Colorado,
Crested Butte,
East River,
GGGSC,
This data release contains self-potential (SP), electrical resistivity tomography (ERT), and water temperature and conductivity data measured during a geophysical survey at the Krause Springs property in Spicewood, Texas. The geophysical survey was completed February 4–15, 2019, over approximately 3.1 acres on the western side of the property adjacent to the main visitor parking lot and entrance facilities. SP data were measured on the land surface within the survey area to locate SP anomalies attributed to groundwater flow. The locations and spatial distribution of the discovered SP anomalies were used to orient four ERT profiles to intersect the SP anomalies. Two ERT profiles, consisting of 84 stainless steel...
Categories: Data;
Tags: Electrical resistivity tomography,
Geophysics,
Groundwater,
Hydrology,
Krause Springs,
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed...
Categories: Data;
Tags: Alaska,
Bonanza Creek Experimental Forest,
ERT surveying,
cryosphere,
electrical resistivity tomography,
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