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. 

Abstract: The paper contains the results of active layer studies in Lorino monitoring site (Eastern Chukotka, Russia), conducted in framework of the Circumpolar Active Layer Monitoring (CALM) program during 2010-2015. The study site includes tundra landscapes of Eastern Chukotka coastal lowlands. The main purpose of the paper is to obtain spatial and temporal patterns of seasonal melting distribution and reveal the main natural factors defining active layer depth within study site. The author demonstrates the predominance of thermal forcing in active layer development, which was strongly complicated by local (microrelief, vegetation, soil moisture, etc.) conditions. These factors determined high spatial and temporal variability of active layer thickness within single grid (100×100 m). The study also reveals the lack of statistical data on natural characteristics and the need for further detailed studies of seasonal melting process.