Periglacial areas in the mountains are characterized by the highest denudation rates, which is due to active physical weathering, significant gradients and low projective vegetation coverage of the slopes of these areas. The accelerated expansion of periglacial areas that has taken place in recent decades is explained by climate changes that contribute to the melting of mountain glaciers. The improved methodology of studying the relief transformation processes, the rates of various exogenous processes, and the features of material redistribution along the pathways of sediment transportation from the slopes to the river valley bottoms contributed to a dramatic increase in quantitative assessment of spatio-temporal changes in the relief of the mountain periglacial zone. The article discusses various traditional and contemporary methods and approaches to studying the periglacial zone relief and its changes. They are divided into two groups: methods of stationary and semi-stationary observations of exogenous processes and methods for studying sediment redistribution in catchments. Various directions are highlighted within each group of methods, special attention is paid to the latest techniques. The results of observations of the rates of various exogenous processes occurring in the periglacial zone are generalized. It is shown that the intensity of rockfall-talus processes depends on lithology and frequency of daily air temperature fluctuation through zero °C and varies from 0.02 to 1.6 mm/year. Avalanche abrasion in avalanche trays reaches 40–70 mm/year. The rate depends on the area of the slope catchment, within which avalanches descend, and corresponds to the rate of denudation for the slope catchment equal to 0.01–0.05 mm/year. Maximum soil erosion rates are typical for young moraine slopes, where it reaches 100 mm/year in the first years after the glacier melts, and after 50 years slows down to 7–10 mm/year. The main flux of sediments is delivered from the slopes to the river bottoms by occasionally formed mudflows.

A new approach to complex assessment of relief for environmental management based on quantitative index of geomorphological safety is developed. The «geomorphological safety» concept, and its implementation as a special type of natural safety is fully determined and proved. The short review of scientific works in the field of risk assessment of geomorphological hazards, stability and vulnerability is provided. An algorithm for conducting a comprehensive assessment of geomorphological safety based on a balanced consideration of factors and conditions of relief development in a particular territory is presented. The procedure and result of evaluation, also the significance of introducing weight coefficients in order to take into account the specifics of land-use are demonstrated using the example of a large-scale assessment of the geomorphological safety of agriculture and mining at a key site in the south of Moscow region. For plain and mountainous topography, as well as for the bottom of the World ocean, the specificity of the assessment procedure by the developed method is emphasized. An overview of significant criteria that should be taken into account when calculating the geomorphological safety index at different scales is given.

Thermokarst lakes and alases are widespread in the North-East of Russia. These structures are part of Quaternary deposit of the region and mostly of Holocene age. The alas complex of the older age is less common. Here we present the study of alas complex sections as old as Lower – Upper Neopleistocene from the Laptev Sea coast (Oyagoss yar, Shirokostan peninsula). The principal composition of these structures of different ages is quite similar. Their formation is correlated with warm intervals when the moisture content increased. Melting of the ice-rich sediment took place locally. Accumulation of the melted water increased the melting and lead to formation of separated thermokarst depressions where succession of the lake-bog-soil sediments with ice-wedge casts (pseudomorphosis) began to accumulate. Current research expands the knowledge about distribution of the alas complex in the north-eastern Russia, allows to recognize its features (the presence of tabers, lacustrine sediments with a complex of pseudomorphs along the ice wedge, the increase in grain size of lacustrine sediments from the center to the periphery of the basins, a large number of values of allochthonous peat in the middle and autochthonous in the top of alas strata), and suggests how to extract paleogeographic information from this type of deposit.

The Curonian and Vistula spit (the Baltic Sea, Kaliningrad Oblast) were formed and developed in similar climatic conditions, but the deflation processes on the spits seashores occur with different intensity, and the forms of the deflation relief differ based on quantitative parameters while coincide in terms of typology. During 2019 field study, 330 blowouts per 25 km were recorded on the surface of the marine foredune of the Russian part of the Vistula spit, i.e. 13.8 blowouts per 1 km on average. In opposite, 333 blowouts per 49 km or 7.1 blowouts per 1 km were recorded on the foredune of the Curonian Spit in 2016. The double prevalence of the number of blowouts per 1 km of the Vistula Spit shore is due to the lack of regulation of tourist activities, in contrast to the Curonian Spit, which has the status of a specially protected natural area. A comparative analysis of the blowouts of the Curonian and Vistula spits showed that a trend in the development of deflation processes is determined by natural and climatic conditions, but an anthropogenic activity affects the intensity of the deflation.

Based on a field study (2019) of the Iturup Island coastal zone relief and interpretation of space images for the period 1980–2019, a morpholithogenetic coastal classification was developed and a map of the coast types was compiled. It was found that 85% of the coasts are eroding. But 80% of the coasts are stable and in fact have not undergone changes during the above mentioned period of time. Erosional coasts with poorly consolidated pyroclastic sediments retreat at an average speed of 2–2.5 m (up to 5 m) per year. Accumulative coasts in different parts of the island experience multidirectional movements: accumulation with an average speed of 1.5–2.5 m (up to 5 m) per year or retreat with an average speed of 1–2.7 m (up to 5.5 m) per year. In large bays, the directions of sediment movement were identified. All of the above mentioned observations are reflected on the coastal dynamics map. Also, the forecast of coastal development for the next 50 years was made. The most dynamic accumulative coasts, in general, will be advancing despite storm and tsunami erosion. The retreat of erosion coasts in poorly consolidated pyroclastics will depend on the height of cliff and the length of coastal collapse section, which determine the amount of material entering the coastal zone. Several sections of the coast (some of the undeveloped ones) were identified as favorable for the construction of berthing facilities.

Geomorphological zoning is as an integrated approach to analyze the land surface and subsequently synthesize the spatial analysis with geomorphological processes developed on it. The main types and objectives of geomorphological zoning are discussed within the framework of a . geomorphologic region , or a modeled geomorphic system. The geomorphological zoning approach is based on understanding of system-wide and geographical laws of the structural and functional integrity of spatial objects within the system. At the same time, the identity of geomorphological region is connected to its internal make-up- element, integrity, structure, stability, dynamics, genesis, and with functioning – transformation of solar energy, moisture circulation, geochemical circulation, biological metabolism, mechanical movement of material under the action of gravity. The main approaches available to date to geomorphological zoning are considered. The main principles of geomorphological zoning are formulated. The conclusion is made about the fundamental possibility of geomorphological zoning in accordance with the stated principles and its, first of all, practical orientation.

The activity of the Yuzhno-Sakhalinsk mud volcano led to a transformation of the relief both directly of the hill itself, on top of which there is a modern eruptive center, and the surrounding territory, in particular, the valleys framing and draining the mud volcano. Periodic filling and blocking of the valleys with flows of mud breccias, displacement and transformation of watersheds, squeezing of watercourse channels with mud flows has been established. Several varieties of terraces and terrace-like surfaces in the valleys of rivers adjacent to the volcano were revealed: 1) erosion or basement terraces developed in the mud breccias deposits, 2) terraceuvals formed by mud flows overlapping alluvial terraces on the slopes of the valleys adjacent to the volcano, 3) mud volcanic pseudo-terraces formed by breccias of different ages and different lengths, 4) landslide terraces in mud volcanic deposits, 5) pseudo-terraces – fragments of mud breccias dams.

Soft-sediment deformation structures have been indentified in glaciolacustrine deposits of the terrace complexes of the Lake Imandra (Kola Region, NE of the Fennoscandian Shield). According to the paleoseismological criteria, we found that these deformation structures were induced by strong earthquakes. These earthquakes led to the occurrence of secondary deformations of various morphology and sizes in the sandy-sandy sediments, forming a single complex consisting of intensely deformed and destructed deposits and associated clastic dikes and cracks. Among the plastic deformations, the phenomena of liquefaction, boudinage structures, flame structures, irregular convolute stratifications, diapir-like structures and synsedimentary folds are developed. Among brittle deformations, cracks and micro-fractures and dykes, predominate. The spatial and stratigraphic distributions of soft-sediment deformation structures were used to infer about the activation of faults during the Late Glacial and Postglacial period of the sub-latitudinal and north-western strike directions that limit the different-scale blocks of the earth’s crust. According to radiocarbon analysis data and paleogeographic reconstructions, the formation of soft-sediment deformations took place at the end of the Young Dryas – the beginning of the Preboreal period between 12900–11500 cal yr BP, and later, in the Preboreal period – beginning of the Boreal period between 11500– 9900 cal yr BP. It was this period that was accompanied by increased seismic activity not only in the Kola region, but also in the whole of Fennoscandia.

A generalization of the materials of a comprehensive paleogeographic study in the ancient glacial region of the Russian Plain is aimed at establishing regional features of the geomorphological structure and patterns of spatial variability of indicators. For these purposes, geological and geomorphological zoning of the territory was carried out on the basis of a systematic approach and under the control of paleogeographic expertise. On the compiled map, the territorial divisions are highlighted: against the background of different age paleogeographic zones, 4 geological provinces and 14 geologic-geomorphological regions are distinguished. Their complex characteristics are obtained by the totality of the leading geomorphological processes. Particular attention is paid to the study of the glacial relief, which plays an important role in paleogeographic reconstructions of this area. Marginal zones infrastructure of the ice sheets of different ages has been studied in detail, which makes it possible to make more exact the maximum and stadial boundaries of the Moscow and Kalinin ice sheets. Thus, regional features of the structure and composition of the morpholithogenic basis of landscapes are established. The laws of its formation are confirmed: geological and geomorphological heredity and paleogeographic conditionality. The study of regional features of the geomorphological structure of the ancient glacial region makes a significant contribution to the reconstruction of the glacial rhythm of the Pleistocene. The results of integrated geologic-geomorphological zoning facilitate the regional targeted estimation of the state of geoecological stability of geosystems and make it more justified.

Water runoff on the slopes of the permafrost zone passes through a network of hollows of various structures and patterns in plan. This is clearly distinguishable on aerial and satellite images, but often poorly distinguished on the ground. The study is aimed at recognizing the reasons for the difference in the structure of the drainage network, which is necessary for understanding the mechanisms of surface runoff generation and the modern relief formation in the permafrost areas. In the vicinity of Anadyr (Chukotka, Russia), three morphological types of the hollow network were identified. In the areas of distribution of each type of hollow network field observations were made, and the morphometric characteristics of the slopes to which they are associated were obtained from the digital surface model and satellite images. Each type of the hollow network corresponds to definite range of altitude, the type of relief, the slope gradient and profile, the composition of the deposits, and the depth of seasonal thawing. It has been established that although all types of troughs are used by temporary streams, they have different mechanisms of development. The hollows with a fan structure form the densest parallel network with a distance of 10–40 m apart. These are characteristic of concave slopes of interfluves with close bedding of bedrock and are the result of fluvial modeling of irregularities formed as a result of uneven sliding of the slope material (gelifluction). The intertwining troughs are confined to the slopes of the volcanic hills, the steepest of the studied ones. Fresh silty sediments have been observed at their bottoms and their formation is associated with erosional processes. Single hollows located at a considerable (200–300 m) distance from each other are formed in loose quaternary deposits with a developed network of ice-wedge-polygons. The role of thermokarst is significant in their deepening.