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TitleElectrical geophysics for assessing permafrost conditions along highway infrastructure
AuthorOldenborger, G A; Stevens, C W; Wolfe, S A
SourceProceeding of the Symposium on the Application of Geophysics to Environmental and Engineering Problems (SAGEEP 2012); 2012 p. 1-7,
Alt SeriesEarth Sciences Sector, Contribution Series 20110334
MeetingSymposium on the Application of Geophysics to Environmental and Engineering Problems; Tucson; US; March 24-29, 2012
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories
Lat/Long WENS-114.5000 -114.0000 62.5000 62.2500
Subjectssurficial geology/geomorphology; engineering geology; ground ice; permafrost; freezing ground; ground temperatures; glacial deposits; glaciolacustrine deposits; electrical resistivity; resistivity; resistivity interpretations; climate change
Illustrationslocation maps; images; profiles
ProgramProgram Management - Climate Change Science, Climate Change Geoscience
AbstractThe Yellowknife region, part of the Slave Geological Province, falls within the extensive discontinuous permafrost zone in Canada. A large degree of economic development is routed through Yellowknife from the mineral-rich North Slave. However, despite the mineral-rich nature of this region, surficial sediment maps and knowledge of permafrost conditions are only now being established in detail. Permafrost and associated ground ice can significantly affect land-based infrastructure through influence on ground stability and drainage patterns. As such, geoscience information contributing to permafrost characterization is critical for understanding risks to roads and airports which are vital to Northern economic development.
The 100 km stretch of the chip-sealed Highway 3, west of Yellowknife, presently experiences instabilities on 30% of the roadway. These include settlement, heave, and rotations related to transitions between differing terrain and drainage conditions within the discontinuous permafrost. Based on the hypothesis of terrain control over permafrost conditions, electrical resistivity data were collected over identified terrain types, and across potential terrain transitions and thaw fronts at selected sites along the highway. Processed resistivity models suggest distinct electrical signatures for most of the terrain types which would allow for extensive geophysical characterization complimentary to landscape mapping, temperature data and shallow boreholes. The resistivity models also exhibit features indicative of the base of ice-bonded permafrost, ice-rich sediment and thaw zones, which can be correlated with terrain features of sediment type and drainage. Observed resistivity anomalies indicate thaw zones related to existing and past road infrastructure, which help in understanding conditions causing highway subsidence.