Geologic - geotechnical characteristics and preservation proposals for the Historic Site and Monument n° 38, Nordenskjöld’s Hut, Antarctica

Abstract

The historic site and monument nº 38, Nordenskjöld Hut, is located on Snow Hill Island, James Ross archipelago, Antarctica. This is a place of great historic and heritage value because there are very few centennial buildings in Antarctica. This building was built in February 1902 as a refuge by the Swedish expedition directed by Otto Nordenskjöld, between 1901 and 1904. The building is located over an embankment with ice-rich permafrost, which produces unstable conditions for the foundation. In the past, anthropic factors accelerated this process, for example, the use of the hut as a refuge and garage for other field campaigns. Intensive and potentially destructive signs are observed as a consequence of the thermokarst and erosion active processes in the last decades, in relation to climate warming. Around the embankment, the erosion processes are connected with underground ice thaw occurring in the top of the permafrost. The embankment area contains 17–20% of underground ice, and the mean active layer depth is 1.2 m. A potential maximum settlement of the embankment top surface between 0.15-0.25 m has been estimated. The above-mentioned processes are a consequence of ice thaw in the permafrost table. This would modify the natural surface and could produce significant damages. This study analyzes contingency and mitigation strategies to prevent or reduce the rate of settlement and avoid altering the top of the embankment. The goal is to protect the slopes and foundation from surface erosion and thermo-erosion. We propose increasing the thickness of the embankment, making a frame on the shoulder of the embankment, and carrying out a retaining wall or socket in the foundation.