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

Abstract

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.

Geophysical mapping of palsa peatland permafrost

“…Ground penetrating radar (GPR) has been used extensively in permafrost studies for identifying the boundaries of permafrost (e.g., Arcone et al, 1998;Doolittle et al, 1992;Hinkel et al, 2001;Moorman et al, 2003), characterizing ground ice structures (De Pascale et al, 2008;Hinkel et al, 2001;Moorman et al, 2003), and estimating seasonal thaw depth and moisture content of the active layer (Gacitua et al, 2012;Westermann et al, 2010). Electrical resistivity tomography (ERT) has also been widely applied in permafrost studies (Hauck et al, 2003;Ishikawa et al, 2001;Kneisel et al, 2000), the majority of which focus on mountain permafrost.…”

High‐resolution seismic and ground penetrating radar–geophysical profiling of a thermokarst lake in the western Lena Delta, Northern Siberia

“…These activities complement shallow seismic (Chirp) measurements collected as a presurvey of the sediment fill in the preceding summer season (see Figure 1). GPR sounding is an established technique for permafrost investigations (Annan and Davis, 1976;Arcone et al, 1998;Judge et al, 1991;Robinson et al, 1997;Hinkel et al, 2001), active layer surveys (Doolittle et al, 1990) and lake-sediment profiling (Mellet, 1995). Mellet (1995) and Moorman and Michel (1997) have shown the potential of the GPR method for surveying sediments through a lake-ice cover.…”

Coupled land surface–subsurface hydrogeophysical inverse modeling to estimate soil organic carbon content and explore associated hydrological and thermal dynamics in the Arctic tundra

“…Geophysical techniques offer an advantage over conventional point measurement techniques because they provide spatially extensive information in a minimally invasive manner (e.g., Hubbard and Rubin, 2005). For example, Arcone et al (1998) and Chen et al (2016) used ground-penetrating radar (GPR) to characterize the depth of the permafrost table. Hinkel et al (2001) used GPR to estimate thaw depth, to recognize ice wedges and ice lenses, and to locate the organic-mineral soil interface.…”