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Open-File Report 2008–1018

Prepared in Cooperation with the State of Nebraska, Conservation and Surveys Division

Helicopter Electromagnetic and Magnetic Geophysical Survey Data, Oakland, Ashland, and Firth Study Areas, Eastern Nebraska, March 2007

By Bruce D. Smith, Jared D. Abraham, James C. Cannia, Gregory V. Steele, and Patricia L. Hill

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Open-File Report
2008-1018 PDF (609 kB)

This report is a digital data release for a helicopter electromagnetic and magnetic survey that was conducted during March 2007 in three 93-square-kilometer (36-square-mile) areas of eastern Nebraska as part of a joint State of Nebraska and U.S. Geological Survey study. The objective of the survey is to improve the understanding of the relationship between surface-water and ground-water systems critical to developing water resource management programs. The electromagnetic equipment consisted of six different coil-pair orientations that measured electrical resistivity at separate frequencies from about 400 hertz to about 115,000 hertz. The electromagnetic data were converted to electrical resistivity geo-referenced grids and maps, each representing different approximate depths of investigation for each area. The range of subsurface investigation is comparable to the depth of shallow aquifers. The three areas selected for the study, Ashland, Firth, and Oakland, have glacial terrains and bedrock that typify different hydrogeologic settings for surface water and ground water in eastern Nebraska. The geophysical and hydrologic information from U.S. Geological Survey studies are being used by resource managers to develop ground-water resource plans for the area.

Version 1.0

Posted May 2008

  • GIS_SURVEY Directory
  • Grids of the electromagnetic and magnetic field data for the horizontal coplanar coil pairs.
  • PLOTS Directory
  • Geotiff (UTM14N. NAD83 projected “.tif” files) images of the grids. Each file has an associated world file (“.tfw”).

Suggested citation:

Smith, B.D., Abraham, J.D. ., Cannia, J.C., Steele, G.V., and Hill, P.L., 2008, Helicopter electromagnetic and magnetic geophysical survey data, Oakland, Ashland, and Firth Study areas, Eastern Nebraska, March 2007: U.S. Geological Survey Open-File Report 2008–1018, 16 p.




Purpose and Scope

Geophysical Data Overview

Helicopter Electromagnetic and Magnetic Survey

Electromagnetic Measurements

Total Magnetic Field Measurements

Ancillary Measurements

Digital Data


GIS Data



Digital Flight line Data


References Cited

APPENDIX I: 2008 Geological Society of America Annual Meeting Poster

APPENDIX II: Fugro Geophysical Report


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