Abstract: The object of this research is the thermokarst occurrences, namely polygonal microrelief and frost cracking, which are the causes of natural hazards for the main water pipeline. The article demonstrates displacements, gaps and cracks in the pipes and fixtures of water mains, caused by thermokarst occurrences; satellite images indicate areal zoning of polygon microrelief. Thermokarst occurrences are detected by satellite images and publicly available on the website https://www.yandex.ru/maps/; the methods of field observation and photosurveying were applied,  the engineering-geological information and library material were processed. The method of areal zoning of the territory of activation of polygonal microrelief is based on the satellite images. The study was conducted by means of field observation on the key sections of the main water pipeline, as well as by processing of archival data acquired from engineering surveys of previous years. The obtained materials allow determining the current geocryological situation of the territory of the water pipeline and spread of negative cryogenic processes and phenomena. Based on the satellite images was described the method od areal zoning of the territory of polygonal microrelief and cracking, earlier proposed by the author. As a result of research, it can be concluded that frost-breaking cracks are the cause of stress-strain state of the water pipeline, and satellite images show the spread of areal zoning of polygonal microrelief and cracking.

Keywords: satellite images, rupture, displacement, waterlogging, thermoerosion, frost-fracturing, thermokarst manifestations, pipeline, main water pipeline, Central Yakutia

Abstract:   In the areas of distribution of permafrost rocks and development of the ice complex, lake thermokarst is the main relief-forming process, which forms a characteristic alas relief. In addition to the formation of lakes, as a result of thermokarst subsidence, accompanied by water runoff, forms the thermo-sculptured relief including Baydzharakh and hummock-hollow forms. This leads to formation of thermokarst occurrences. The object of this research is thermokarst occurrences, namely, polygonal microrelief and frost splitting, explored in the section of the main water pipeline “Lena – Tuora-Kyuel – Tatta”, near the settlement of Maya Megino-Kangalassky Ulus of the Sakha Republic (Yakutia). These thermokarst occurrences were identified from the satellite images that are publicly available on the Internet. The author also applied processing technique of engineering and geological data, literary and library materials were also used in the work. Field research and simple photography were also used for determining the shape and size polygons. The main conclusion consists in suggesting simple method that allows to conduct area zoning of the territory for activation of the polygonal microrelief as thermokarst occurrences. The research results of area zoning related to distribution of cryogenic processes can be used in technical-economic substantiation of the choice of routes of linear and other constructs.  

Keywords: main water pipeline, satellite images, underground ice, frost-breaking fracturing, polygonal microrelief, thermokarst, thermokarst manifestations, Central Yakutia, Maya village, technique of zoning

Abstract: The study of coastal dynamics and associated permafrost processes is a relevant issue in connection with the active development at the Russian Arctic coast. In addition to wave and ice effects on the coastal dynamic, the shores composed of permafrost unlithified sediments, permafrost (cryogenic) processes have a significant effect: thermoabrasion, thermodenudation, thermokarst, and linear thermoerosion. The purpose of this study is to quantify the impact of various cryogenic processes upon the coastline retreat rate on a key site at the Ural coast of the Baydaratskaya Bay, Kara Sea. Coastal retreat rates were estimated based on the interpretation of satellite images (QuickBird-2 2005, WorldView-1 2012, WorldView-2 2013, WorldView-2 2016) and field leveling surveys in 2013, 2014, 2015 and 2017 for zones with prevailing exogenous processes. As a result, coastline rates were obtained under the influence of various cryogenic processes. The revealed differences showed a significant contribution of these processes to the coastal dynamics, along with the geological and geomorphological structure and different time-periods. The performed quantitative estimation will allow conducting more substantiated modeling and forecasting for the development of certain sections of the Russian Arctic coast.

Keywords: Kara Sea, Baydaratskaya Bay coast, thermokarst, linear thermoerosion, thermodenudation, coastal dynamics, remote sensing, permafrost, permafrost processes, monitoring

Abstract: The research objects are permafrost sediments and frost mounds in the Sentsa river valley. The problem of their formation in the alluvium period attracts the attention of many scholars in different fields of study (from geo-botanists to specialists in geo-cryology). The complex pilot studies included boreholes drilling, detailed documentation of frost borehole samples, penetrated sections of frost mounds, and river terrace cusps, tacheometric survey of the Sentsa river valley, GPS-anchoring of reference sections and boreholes, defining the ice content (humidity), and the lithological, grain-size and microaggregate composition of lacustrine-alluvial sediments. The analysis has been performed by the specialists of the shared knowledge center “Geodynamics and geochronology” (the Institute of the Earth’s Crust of the Siberian Branch of the Russian Academy of Sciences, Irkutsk) using the modern methods. The authors conclude that frost mounds consist mainly of silt loams with the interlayers of heavy clay sand and ice lenses (up to 0,65 m). Cryo-textures are fissile, crossbedded, thick-schlier, wide-meshed, basal. The designed 3D model of the relief speaks for the presence of either a vast area with many frost mounds of different sizes, or of one gigantic mound, which at the present time is defragmented due to active thermokarst on a terrace above the flood-plain and thermoerosion of the sides of the Sentsa river. According to the preliminary data, frost mounds are cryogenic formations of a mixed segregation-intrusive genesis. The final goal of the research is the elaboration of a scenario of formation of permafrost lacustrine-alluvial sediments and the creation of a theoretic model of the Holocene evolution of frost mounds of the Oka plateau. 

Keywords: 3D-model of relief, ice content, grain-size composition, cryogenic structures, lithology, permafrost lacustrine-alluvial sediments, frost mounds, ice lenses, segregation-intrusive ice formation, Oka plateau