| Title | Geophysical characterization of permafrost at Iqaluit International Airport, Nunavut |
| |
| Author | Oldenborger, G A ;
LeBlanc, A -M; Short, N H; Sladen, W E; Allard, M |
| Source | Arctic Change 2014, poster abstracts; by ArcticNet; 2014 p. 125 |
| Links | Online - En ligne
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| Year | 2014 |
| Alt Series | Earth Sciences Sector, Contribution Series 20140322 |
| Publisher | Arctic Net |
| Meeting | Arctic Change 2014; Ottawa; CA; December 8-12, 2014 |
| Document | book |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Nunavut |
| NTS | 25N/15 |
| Area | Iqaluit |
| Lat/Long WENS | -68.5667 -68.5333 63.7667 63.7333 |
| Subjects | surficial geology/geomorphology; engineering geology; Nature and Environment; permafrost; freezing ground; ground ice; ground temperatures; frost cracks; frost heaving; satellite imagery; thermal
analyses; thermal regimes; RADARSAT-2 |
| Illustrations | location maps; graphs; profiles; images |
| Program | Climate Change Geoscience Land-based Infrastructure |
| Released | 2014 01 01 |
| Abstract | Iqaluit International Airport presently suffers from instabilities and subsidence along its runway, taxiways and apron. These instabilities may be related to permafrost, permafrost degradation and
associated drainage conditions. In particular, asphalt surfaces are significantly impacted by permafrost degradation, thaw settlement and frost cracking. As part of a joint activity involving the Canada-Nunavut Geoscience Office, the Geological
Survey of Canada and Université Laval, several types of electrical and electromagnetic geophysical data have been collected over and around airport infrastructure to characterize permafrost conditions and to investigate active permafrost processes
including seasonal changes in unfrozen water content and the role of unfrozen water. Even with continuous permafrost and cold permafrost temperatures, the data often indicate material types with low electrical resistivity, suggesting fine-grained
marine sediments and/or saline porewater with the potential for freezing point depression and significant unfrozen water content. In particular, electrical conductivity anomalies beneath taxiways and the runway are correlated with localized
settlement problems and with downward multi-season displacement as derived from D-InSAR, and indicate potential zones of groundwater influence. We observe variable active layer thickness under infrastructure that is generally thicker than for
undeveloped ground. The thawing front extends downward beneath the embankment material in the underlying glaciomarine sediments such that settlement due to melting of ice wedges or other ice rich materials is likely to continue. Observed seasonal
changes in the data indicate that subsurface temperature fluctuations may result in significant ice formation near the thaw table and changes in unfrozen moisture content in the permafrost. Unfrozen water content is an important parameter in
calculating the thermal properties of soil, which is used to predict the behaviour of the ground upon warming and thawing. |
| Summary | (Plain Language Summary, not published)
Iqaluit International Airport presently suffers from instabilities and subsidence along its runway, taxiways and apron. These instabilities may be
related to permafrost, permafrost degradation and associated drainage conditions. In particular, asphalt surfaces are significantly impacted by permafrost degradation, thaw settlement and frost cracking. As part of a joint activity involving the
Canada-Nunavut Geoscience Office, the Geological Survey of Canada and Université Laval, several types of geophysical data have been collected over and around airport infrastructure to characterize permafrost conditions and to investigate active
permafrost processes. The geophysical surveys reveal anomalies related to multi-season displacement and groundwater influence. |
| GEOSCAN ID | 295575 |
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