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Electrical resistivity tomography (ERT) and horizontal-to-vertical spectral ratio (HVSR) data collected east of Box Elder, South Dakota, in 2021

Metadata Updated: October 29, 2023

The U.S. Geological Survey, in cooperation with the U.S. Air Force Civil Engineer Center, used surface geophysical methods to delineate the top of the Cretaceous Pierre Shale along survey transects in selected areas east of Ellsworth Air Force Base, South Dakota. In 2019, the U.S. Geological Survey performed passive seismic and 2D electrical resistivity tomography (ERT) surveys along 21 co-located survey transects east of Ellsworth Air Force Base. Passive seismic data were analyzed using the horizontal-to-vertical spectral ratio (HVSR) method in the Grilla software suite ( to determine the fundamental resonance frequency peak at each site. Passive seismic data were also collected at existing well sites and the average shear wave velocity for unconsolidated deposits overlying the Pierre Shale was used to calculate the depth to Pierre Shale along survey transects. ERT data were processed using EarthImager2D software from Advanced Geosciences, Inc. ( to remove noisy measurements and produce subsurface resistivity profiles that were interpreted to estimate the depth to the Cretaceous Pierre Shale. HVSR results were plotted with ERT profile results to delineate a continuous bedrock surface for each survey transect. The continuous bedrock surface results were converted to elevations using light detection and ranging (liDAR) elevation data and were extracted to electrodes locations that were part of ERT surveys for each survey transect. The unprocessed and processed data for each geophysical surveys and bedrock delineation are provided as either comma-separated values (.csv) files or zipped folders (.zip) and annotated accordingly in the metadata.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date October 29, 2023

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date October 29, 2023
Publisher U.S. Geological Survey
Identifier USGS:62558e6bd34e21f8276f48c8
Data Last Modified 20221219
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 4b219157-9a7e-4f44-8c3a-35a758ce7411
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -103.07552,44.10178,-102.94989,44.15319
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash 038c85eb4313815a9cfac9241bd4a9285d21a835ed8f13246c986a6b12cbfd46
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -103.07552, 44.10178, -103.07552, 44.15319, -102.94989, 44.15319, -102.94989, 44.10178, -103.07552, 44.10178}

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