Impulse radar experiments on permafrost near Tuktoyaktuk, Northwest Territories

Davis, J. L.; Scott, W J; Morey, Rexford M.; Annan, A. P.

doi:10.1139/e76-165

Cited by 24 publications

(10 citation statements)

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“…Ground-penetrating radar (GPR) could bridge this gap, because it can assess the volumetric composition of the soil through the differences in the dielectric properties of the constituent materials. GPR has for a long time been used to map the geological composition of the ground in permafrost regions [Davis et al, 1976], Figure 1. Schematic view of the measurement setup.…”

Section: Introductionmentioning

confidence: 99%

Methane emission bursts from permafrost environments during autumn freeze‐in: New insights from ground‐penetrating radar

Pirk

Santos

Gustafson

et al. 2015

Geophysical Research Letters

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Large amounts of methane (CH4) are known to be emitted from permafrost environments during the autumn freeze‐in, but the specific soil conditions leading up to these bursts are unclear. Therefore, we used an ultrawide band ground‐penetrating radar in Northeast Greenland in autumn 2009 to estimate the volumetric composition inside the soil through dielectric characterization from 200 to 3200 MHz. Our results suggest a compression of the gas reservoir during the phase transition of soil water, which is accompanied by a peak in surface CH4 emissions. About 1 week thereafter, there seems to be a decompression event, consistent with ground cracking which allows the gas reservoir to expand again. This coincides with the largest CH4 emission, exceeding the summer maximum by a factor of 4. We argue that these complementary measurement techniques are needed to come to an understanding of tundra CH4 bursts connected to soil freezing.

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Section: Introductionmentioning

confidence: 99%

Methane emission bursts from permafrost environments during autumn freeze‐in: New insights from ground‐penetrating radar

Pirk

Santos

Gustafson

et al. 2015

Geophysical Research Letters

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“…To date, permafrost features such as massive ice (Bertram et al, 1972;Annan and Davis, 1976;Davis et al, 1976;Arcone et al, 1982;Dallimore and Davis, 1992;Pilon et al, 1992) and isolated thaw zones (Arcone et al, 1992), and suprapermafrost interfaces between thawed and frozen materials (Pilon et al, 1979;Arcone and Delaney, 1982;Delaney et al, 1990;Doolittle et al, 1990) have been interpreted from GPR profiles. Frozen silts, which cover much of the uplands of interior Alaska, generally prevent radar penetration to the bottom of permafrost because the silts have high attenuation rates (Hoekstra and Delaney, 1974;Delaney and Arcone, 1984;Arcone and Delaney, 1989).…”

Section: Introductionmentioning

confidence: 99%

Ground‐penetratinng radar reflection profiling of groundwater and bedrock in an area of discontinuous permafrost

et al. 1998

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We have used ground-penetrating radar to profile the depth to permafrost, to groundwater beneath permafrost, and to bedrock within permafrost in alluvial sediments of interior Alaska. We used well log data to aid the interpretations and to calculate dielectric permittivities for frozen and unfrozen materials. Interfaces between unfrozen and frozen sediments above permafrost were best resolved with wavelet bandwidths centered at and above 100 MHz. The resolution also required consideration of antenna configuration, season, and surface conditions. Depths to subpermafrost groundwater were profiled where it was in continuous contact with the bottom of the permafrost, except near transitions to unfrozen zones, where the contact appeared to dip steeply. The complexity of the responses to intrapermafrost bedrock, detected at a maximum depth of 47 m, appears to distinguish these events from those of subpermafrost saturated sediments. The relative dielectric permittivity ranged between 4.4 and 8.3 for the permafrost, and between 12 and 45 for partially to fully saturated, unfrozen silts and sands. Scattering losses are evident from intrapermafrost diffractions and from the improved penetration achieved by lowering the midband radar frequency from 100 to 50 MHz.

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“…Consideration of radar techniques has been avoided in this paper, since such techniques have been recently treated by other authors (Davis et al 1976).…”

Section: Discussionmentioning

confidence: 99%

“…the ice core. These experiments have included radar (Davis et al 1976), up-hole wavefront mapping, VLF resistivity profiling, and density logging in boreholes.…”

Section: Involuted Hill Test Sitementioning

confidence: 99%

Applications of geophysical techniques in permafrost regions

Scott¹,

Hunter²

1977

Can. J. Earth Sci.

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This paper reports the results of some recent geophysical experiments carried out in the Arctic with a variety of methods. In the Beaufort Sea, seismic refraction profiles obtained with both source and receivers on the seabottom indicate the presence of discontinuous near-bottom high-velocity (4200 m/s) material interpreted to be presently aggrading permafrost. Spring-time resistivity soundings taken through the ice in Kugmallit Bay, Beaufort Sea, show the top of permafrost at about 50 m below the bottom. Even for 5-km spreads, the base of permafrost was not observed.Off the southeast coast ofMelville Island, refraction seismic profiles shot on the seabottom and resistivity soundings made through summer ice yielded data which correlate with known subbottom geology, but which gave no clear indication of either presence or absence of permafrost.Seismic and resistivity measurements made at a number of control sites in the Arctic Islands yielded typical velocities of 3500 mls and resistivities of 1 x lo6 ohm-m for ice-saturated sands.Some correlation was observed between seismic velocity and moisture contents in the range from 10% to 40%. Seismic and resistivity results in IOL Lake at the Involuted Hill test site, Tuktoyaktuk Peninsula, suggest the absence of permafrost under some parts of the lake bottom. On the hill itself, seismic up-hole shooting and VLF resistivity profiling give interpretations of ice distribution which correlate well with drill control. Gamma-gamma logs taken in some of the drill holes correlate well with ice content logged during drilling.

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Impulse radar experiments on permafrost near Tuktoyaktuk, Northwest Territories

Cited by 24 publications

References 0 publications

Methane emission bursts from permafrost environments during autumn freeze‐in: New insights from ground‐penetrating radar

Methane emission bursts from permafrost environments during autumn freeze‐in: New insights from ground‐penetrating radar

Ground‐penetratinng radar reflection profiling of groundwater and bedrock in an area of discontinuous permafrost

Applications of geophysical techniques in permafrost regions

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