| Title | Detection of ice wedge cracking in permafrost using miniature accelerometers |
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| Author | O'Neill, H B ;
Christiansen, H H |
| Source | Journal of Geophysical Research, Earth Surface vol. 123, issue 4, 2018 p. 642-657, https://doi.org/10.1002/2017JF004343 |
| Image |  |
| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20180043 |
| Publisher | Wiley-Blackwell |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Area | Adventdalen; Norway; Svalbard and Jan Mayen |
| Lat/Long WENS | 15.5000 16.0000 78.5000 78.0000 |
| Subjects | surficial geology/geomorphology; geophysics; Nature and Environment; permafrost; ground ice; periglacial features; ice wedges; ice-wedge polygons; stress analyses; thermal analyses; ground temperatures;
seismology |
| Illustrations | location maps; satellite images; schematic cross-sections; time series; histograms; bar graphs; tables; graphs; schematic diagrams |
| Program | Climate Change
Geoscience Permafrost |
| Released | 2018 04 19 |
| Abstract | Determining the exact timing of ice wedge cracking in permafrost is challenging. Five miniature accelerometers were installed near the ground surface in the trough of a primary ice wedge within a
network of low-centered polygons in Adventdalen, Svalbard, to test whether these instruments could be used to detect dynamics of thermal contraction cracking. Data from 2003 to 2013 were analyzed to characterize cryoseismic signals in the ice wedge
trough. High-magnitude accelerations (from 5 g to at least 100 g) were typically registered in late winter, when the top of permafrost had cooled to about -10°C; these likely correspond to ice wedge cracking in permafrost. Tensile stresses calculated
from temperatures measured in the ice wedge trough are near laboratory strengths reported for ice and mineral active layer sediments, supporting the interpretation that large accelerations are caused by thermal contraction cracking. Lower magnitude
accelerations occurred throughout the freezing season, usually coinciding with rapid cooling at the ground surface. These small accelerations may be associated with (i) the initiation of small cracks in the active layer of the trough or (ii) the
horizontal and vertical propagation of existing ice wedge cracks. The results of this investigation indicate that miniature accelerometers are an effective, inexpensive, and simple method to determine the timing of ice wedge cracking and rates of
crack propagation along ice wedge troughs. |
| Summary | (Plain Language Summary, not published)
Five small accelerometers were installed near the ground surface in the trough of an ice wedge to test whether these instruments could be used to detect
ice-wedge cracking. High magnitude accelerations were typically registered in late winter, when the top of permafrost had cooled to about -10 °C; these likely correspond to ice-wedge cracking in permafrost. Lower magnitude accelerations occurred
throughout the freezing season, usually coinciding with rapid cooling at the ground surface. These small accelerations may be associated with (i) the initiation of small cracks in the active layer of the trough, or (ii) the horizontal and vertical
propagation of existing ice-wedge cracks. |
| GEOSCAN ID | 308216 |
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