ИСТИНА

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 and 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).