Geophysical identification of permafrost in Livingston Island, maritime Antarctica

Abstract

[1] The current permafrost distribution on Livingston Island, South Shetland Islands, maritime Antarctic, was investigated using electrical resistivity tomography, refraction seismics, and shallow borehole temperatures. The field sites include different geological and geomorphological settings, including ice cored moraines and bedrock sites with debris covers of different thickness. Two-dimensional geophysical inversion schemes were used to analyze spatial heterogeneity at field sites and to detect isolated occurrences of ground ice. Results confirm that permafrost is widespread on Livingston Island, with high ice content in ice cored moraines and little in the cracks and fissures of frozen bedrock. Specific electrical resistivity values range from 10,000-40,000 ohm-m (frozen unconsolidated material) to 1500-10,000 ohm-m (frozen quartzite/shale). Combining seismic P wave velocities and specific electrical resistivities, a typical ''roof-type'' distribution was found with maximum resistivities coinciding with P wave velocities around 3000 m/s and decreasing resistivities for both increasing and decreasing velocities.

Local influences of geothermal anomalies on permafrost distribution in an active volcanic island (Deception Island, Antarctica)

“…They show two distinct zones: (1) the alluvial fan next to the lagoon, where specific electrical resistivity values at depth range from 12 to 32 k-ohm-m; and (2) the upper sector of the alluvial fan and debris cones, and on the surface layer near the lagoon where resistivity values range from 1.5 to 10 M-ohm-m. These values are considerably higher than the range of resistivity values found in previous electrical resistivity surveys on Deception and Livingston Island (Hauck et al, 2007) and also than in the European Alps (Hauck and Vonder Mühll, 2003). Such high values may be due to that some electrodes were located in very dry ash.…”

“…Because a marked increase in electrical resistivity occurs at the freezing point, electrical methods are most suitable to detect, localize and characterize structures containing frozen material (Hauck et al, 2007). Geophysical techniques show very low environmental impact and are therefore very valuable for application in a sensitive and protected environment like the Antarctic Specially Managed Area of Deception Island (ASMA nr 4).…”

Thermal state of permafrost and active‐layer monitoring in the antarctic: Advances during the international polar year 2007–2009

“…. Active rock glaciers and ice-cored moraines are present down to sea-level (Serrano and López-Martínez 2000;Hauck et al, 2007;Vieira et al, 2008), accompanied by what are probably relict permafrost bodies. The distribution of permafrost is complex in the South Shetlands archipelago, and several low-elevation boreholes show the presence of permafrost with temperatures close to 08C, especially beneath diamictons or in sedimentary materials.…”

Permafrost and active layer monitoring in the maritime Antarctic: Preliminary results from CALM sites on Livingston and Deception Islands

“…30 m asl) (Serrano and López-Martinez, 2000). Meteorological and geophysical data indicate, however, that environmental conditions in the islands are marginal for the maintenance of permafrost (Hauck et al, 2007). Moreover, in areas of volcanic activity (e.g.…”

“…Among the objectives of these projects is the installation of a network of boreholes for permafrost temperature monitoring, a network of sites for monitoring active layer characteristics (CALM-S), and studies of the energy fluxes between the ground and the atmosphere. The PERMAMODEL project (Hauck et al, 2007), which involves monitoring and modelling permafrost and activelayer dynamics on Livingston and Deception Islands, is part of the ANTPAS and TSP projects and will contribute to the monitoring strategy by installing new boreholes and CALM-S sites on these islands. This paper describes experimental designs established at the field research sites to record the thermal regime and the behaviour of the active layer in different places with similar climatology, but having different soil composition, porosity, and water content.…”