Surface-geophysical investigation of a formerly used defense site, Machiasport, Maine, February 2003

Eric A. White

doi:10.3133/sir20045099

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Surface-geophysical investigation of a formerly used defense site, Machiasport, Maine, February 2003

Eric A. White

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Abstract

Surface-geophysical surveys were conducted in February 2003 at a formerly used defense site in Maine, where residual chlorinated solvents are affecting off-site domestic water-supply wells. The U.S. Geological Survey and Argonne National Laboratory used surface-geophysical methods, including ground-penetrating radar and seismic-refraction tomography, to characterize the lithology and structure of the bedrock at the site and to identify highly fractured areas that may provide pathways for ground-water flow and contaminant transport. Multifrequency electromagnetic and inductive terrain-conductivity methods also were evaluated, but these techniques were adversely affected by a nearby naval computer and telecommunications station. Interpretation of the data from ground-penetrating radar indicates that depth to the weathered bedrock surface is approximately 0.5 to 3 meters. Reflections from within the bedrock are visible throughout all ground-penetrating radar profiles, and zones of scattered electromagnetic energy may correlate to zones of highly fractured bedrock. Interpretation of the data from seismic-refraction tomography inversion indicates that zones of relatively low seismic velocity and topographic lows may correlate with fractured and water-producing intervals within the bedrock. Integrated interpretation of the results from ground-penetrating radar and seismic-refraction tomography was used to locate boreholes along the surface-geophysical profiles. An integrated analysis of information obtained from the surface- and borehole-geophysical surveys and test drilling will be used by the U.S. Army Corps of Engineers to develop a conceptual model of ground-water flow and solute transport at the site.

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Source-reported bounding extent: 44.625° to 44.65833333° latitude; -67.40416667° to -67.37916667° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Eric A. White. 2005. Surface-geophysical investigation of a formerly used defense site, Machiasport, Maine, February 2003. https://doi.org/10.3133/sir20045099

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