GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 ___ GNGTS 2023 Geophysical and geocryological surveys for active layer and permafrost characterization in the Khanovey Railway Station area, Komi Republic, NE European Russian Arctic M. Rossi 1 , M. Dal Cin 2 , S. Picotti 2 , D. Gei 2 , V.S. Isaev 3 , A.V. Pogorelov 3 , E.I. Gorshkov 3 , D.O. Sergeev 4 , P.I. Kotov 3 , M. Giorgi 2 , M.L. Rainone 5 1 Università degli Studi di Parma, Parma, Italy 2 National Institute of Oceanography and Applied Geophysics – OGS, Trieste, Italy 3 Faculty of Geology, Lomonosov Moscow State University, Moscow, Russia 4 Sergeev Institute of Environmental Geoscience, Moscow, Russia 5 Università degli Studi G. D’Annunzio Chieti—Pescara, Chieti, Italy Arctic amplification, the proven phenomenon for which Arctic is warming about twice as fast as the rest of the world, represents one of the main concerns related to permafrost retreat and degradation (IPCC, 2017; Biskaborn et al., 2019; NOAA/NASA, 2020; NSIDC 2020). Rising temperatures are leading to a gradual deepening of permafrost table, reducing the ground capacity to carry loads and, therefore, causing subsidence and deformation of infrastructures (e.g. Chen et al., 2014). Characterization of permafrost distribution and dynamics, in terms of the active layer thickness (ALT) variations, is therefore crucial to assess stability of engineering infrastructures. The aim of this research is the investigation and monitoring, by a multidisciplinary approach, of the ALT in the Arctic area of the Khanovey railway station (Komi Republic, Russia). Khanovey site is an example of permafrost degradation process at a metastable stage, referred to as “climate-driven, ecosystem-protected permafrost” (Vasiliev et al., 2020). Here permafrost degradation, thermokarst processes and gradual lowering of the permafrost table lead to vertical deformation (up to 2.5 cm yr − 1) of the North Russian Railway roadbed, a process accelerated by removal of peat with change in the thermal regime during the construction (Voytenko and Sergeev, 2016; Vasiliev et al., 2020). ALT characterization is one of the keys to monitor the degree of permafrost degradation, providing essential geocryological information for engineering solutions (e.g. thermosyphon and insulation cover technologies, Wagner, 2014). The survey area, about 1 km2 of extension (Fig. 1), is located in the Bolshezemelskaya tundra, about 60 km west of the foothills of the Ural Mountains and it is delimited by the Vorkuta River bank on the eastern side and by the North Russian Railway on the western side. This railroad