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Geophysical identification of permafrost in Livingston Island, maritime Antarctica
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Orientador(es)
Resumo(s)
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.
Descrição
Palavras-chave
Permafrost Geophysical surveys Electrical resistivity tomography Refraction seismics Maritime Antarctica Livingston Island
Contexto Educativo
Citação
Hauck, C., Vieira, G., Gruber, S., Blanco, J., & Ramos, M. (2007). Geophysical identification of permafrost in Livingston Island, maritime Antarctica. Journal of Geophysical Research-Earth Surface, 112(F2). https://doi.org/10.1029/2006JF000544.
Editora
American Geophysical Union