Time-Domain Electromagnetic Surveys at Fort Irwin, San Bernardino County, California, 2010–12

Open-File Report 2013-1024- F
Prepared in cooperation with the U.S. Army, Fort Irwin National Training Center
By:  and 
Edited by: David C. Buesch

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Abstract

Between 2010 and 2012, a total of 79 time-domain electromagnetic (TEM) soundings were collected in 12 groundwater basins in the U.S. Army Fort Irwin National Training Center (NTC) study area to help improve the understanding of the hydrogeology of the NTC. The TEM data are discussed in this chapter in the context of geologic observations of the study area, the details of which are provided in the other chapters of this volume. Selection of locations for TEM soundings in unexplored basins was guided by gravity data that estimated depth to pre-Tertiary basement complex of crystalline rock and alluvial thickness. Some TEM data were collected near boreholes with geophysical logs. The TEM response at locations near boreholes was used to evaluate sounding data for areas without boreholes. TEM models also were used to guide site selection of subsequent boreholes drilled as part of this study. Following borehole completion, geophysical logs were used to ground-truth and reinterpret previously collected TEM data. This iterative process was used to site subsequent TEM soundings and borehole locations as the study progressed. Although each groundwater subbasin within the NTC boundaries was explored using the TEM method, collection of TEM data was focused in those basins identified as best suited for development of water resources. At the NTC, TEM estimates of some lithologic thicknesses and electrical properties in the unsaturated zone are in good accordance with borehole data; however, water-table elevations were not easily identifiable from TEM data.

Suggested Citation

Burgess, M.K., and Bedrosian, P.A., 2014, Time-domain electromagnetic surveys at Fort Irwin, San Bernardino County, California, 2010–12, chap. F of Buesch, D.C., ed., Geology and geophysics applied to groundwater hydrology at Fort Irwin, California: U.S. Geological Survey Open-File Report 2013–1024, 64 p., https://doi.org/10.3133/ofr20131024F.

ISSN: 2331-1258 (online)

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Time-domain electromagnetic surveys at Fort Irwin, San Bernardino County, California, 2010–12
Series title Open-File Report
Series number 2013-1024
Chapter F
DOI 10.3133/ofr20131024F
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description Report: v, 64 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Geology and geophysics applied to groundwater hydrology at Fort Irwin, California
Country United States
State California
County San Bernardino County
City Fort Irwin
Online Only (Y/N) Y
Additional Online Files (Y/N) N