Abstract: The article presents preliminary results of field studies of the outcrops of the eastern coast of the Chukchi Peninsula, containing massive ice beds. The expeditions were conducted in 2014–2018. Descriptions and photographs of ice and enclosing sediments are given. Four outcrops of ice up to 4.7 m thick and up to 45 m long are described within the Saint Lawrence Bay and Mechigmensky Bay. The morphology of the massive ice bodies, a variety of ice structures and host sediments allow suggesting their polygenetic origin. The results of long-term active layer thickness monitoring indicated that the intensification of thaw slump events in the past four years is associated with the increase in the depth of thawing, which in 2018 reached highest values in over two decades. The formation of thaw slumps and associated thermocirques is cyclic. As the active layer thickness increases, their number increases, forming nested thermocirques, and as the thaw depth decreases, cryogenic creep slows down.

Abstract:  This article presents and tests the method of assessment of the various geocriological threats to the developed territories of Eastern Chukotka. The research is based on the complex of field geodesic, geophysical, and geocryological measurements conducted in the core settlement of the indicated region (Lorino), as well as archival data of the engineering surveys of previous years. Based on the acquired materials using the calculation methods, the author was able to determine the current geocryological situation in subsoil of the settlement along with the development level of the negative cryogenic processes and phenomena. In the course of this war was performed the assessment of threats associated with the changes in cryogenic situation and development of the negative cryogenic processes. As a result of this research, the author allocated the sections of settlement within which is traced the low level of natural sustainability of lithocryogenic ground in terms of technogenic disturbance, as well as high level of threat pertaining to decline in the carrying capacity of refrigerated piles and increase of tangential forces of frost heaving of soil.

Abstract: The article contains the results of field investigations of cryospheric objects – land-based glaciers and permafrost rocks in the area of the Lavrenty Bay, Eastern Chukotka. Glaciers of the Laurentian group were described in the mid-1970s by Rudolf Sedov, later they were studied with the help of space imagery by one of the authors. Since glaciers are of small size, and satellite images can give errors in this case, it was necessary to check in situ their condition. Field studies have made it possible to ascertain the severe degradation of small glaciers of the Chukchi Highlands. Also field studies of the permafrost seasonal thawing, carried out by the authors in the season of 2017, revealed that the difference in thickness of the seasonally thawed layer in the study area at the end of August was, in comparison with the previous year, -0.5 .. + 4.3 cm, depending on local natural conditions.