ИСТИНА

Sea coasts are the basis for the industrial facilities for oil and gas exploration in the Arctic. The establishment of a geothermal coastal station for long-term year-round monitoring of the ground temperature in natural conditions prior to the economic development of the territory will provide the necessary recommendations on the magnitude of man-made deformations for the safe operation of designed facilities and engineering structures and avoid catastrophic events of coastal retreat and floods. In the present work, the results of long-term field measurements of ground temperatures which were carried out at Pesyakov island near Varandey settlement (Pechora Sea coast) in the period 2012-2018. Geothermal station consists of five boreholes with a depth of 2.3 to 6.5 m. Each borehole has GeoPrecision thermostrings with temperature sensors and wireless radio mini data loggers M-Log5W-DALLAS, which automatically record measurement data and store them. Thermostring have a length of 10 m and include 20 sensors located across 0.25–1 m. The boreholes are laid in various geomorphological positions along the line passing across the central part of Pesyakov island: the upper part of the beach at the foot of the coastal bluff, the top of the dune belt near the edge of the coastal bluff, the surface of the terrace behind the dune belt (3 boreholes), layda. It has been established that the episodic deviations of the ground thawing duration from the mean annual values do not directly affect the deformation of the coast. However, a directional increase in the duration of the warm period leads to an increase in the thickness of the active layer, reducing the thermodynamic stability of the sea coasts. The study was carried out by a grant from the Russian Science Foundation (Project No. 17-77-10140).