In 2019, the observation network of the Yakutsk branch of the Federal Research Center of the Uni ed Geophysical Service of the Russian Academy of Sciences (YB FRC EGS RAS) became completely digital, and earthquake catalogs became highly representative due to the network density (especially in south Yakutia). The improved registration capabilities de ne the prospects for real-time seismic hazard monitoring. Research on earthquakes is mainly aimed at ensuring the safety of human life. With the development of modern civilization and technical equipment, natural phenomena pose an increasing threat to humans. In addition, earthquakes, even not very strong ones, can cause man-made disasters. The aim of this work was to assess the macroseismic effect of the Nimnyr earthquake in MSK-64 scale points, which was recorded on January 18, 2021 in the Aldan Highlands in South Yakutia. To achieve this goal, the following tasks were formulated: survey of settlements, survey of residents, construction of isoseist maps, and modeling of the terrain. This paper presents the data of macroseismic survey in the epicentral zone of the earthquake. The data obtained represent the primary factual material collected on the basis of “fresh traces” and gives an idea of the intensity of shaking in the far and near zones and the exact location of the earthquake source. A survey of settlements and a survey of residents made it possible to assess the macroseismic effect in points of the MSK-64 scale. An isoseismic map of the seismic event was constructed. Some materials of remote sensing data processing for building a digital terrain model are presented. The constructed digital model will make it possible to track the consequences of tremors, leading to negative and positive landforms, which can be of great height and steepness.

The article is dedicated to the 130th anniversary of Sergei Vladimirovich Obruchev, the legendary pioneer who began the study of geography, geology and, in general, the natural features of the unexplored Arctic territories of the Russian northeast, who experienced physical and moral and psychological human capabilities in extreme conditions, relying only on his own titanic performance, organization and wise wit. The routes of the Obruchev’s expedition in 1929-1930 along the Kolyma territory were chosen as optimally as possible, so that to cover in circle the Kolyma River and its right tributaries Korkodon and Omolon, in order to reveal the main geographic and geological structure of the Kolyma region. This gave the rst solid idea of the geological structure with its Precambrian crystalline rocks and overlying Phanerozoic and Cenozoic sedimentary strata and draw the conclusion about the consolidated rigid tectonic structure of this part of the earth’s crust, which is fundamental. Further, with the development of the knowledge, discussions and disputes about the tectonic nature of the Kolyma territory ared up more and more, and now they do not subside. The geology of the territory turned out to be very complex and intriguing; therefore, a lot of research was carried out by various industrial and scienti c organizations. Hwever, they were carried out separately and haphazardly. This problem was more thoroughly solved by the results of areal prospecting and geological survey operations at the scale of 1:50,000, carried out consistently and systematically with advanced production (scienti c) and methodological studies of the Central exploration and survey expedition of Yakutskgeologiya JSC (in those years, the Geophysical Expedition - (GFE) No. 6 PGO “Yakutskgeologiya”) in the 1980-1990s.

Mineral exploration activities require robust predictive models that result in accurate mapping of the probability that mineral deposits can be found at a certain location. Currently, a signi cant part of the mineral deposits on the surface have already been found. As a result, new search principles become noticeably more complicated, which requires the use of more complex methods for analyzing spatial data. Modern GIS allows analyzing and integrating geospatial information from different sources. In this work, the analysis of geological, geochemical and geophysical data was carried out on the example of an ore region located in the inter uve of the Iengra and Timpton Rivers. To establish the patterns of distribution of gold mineralization, an analysis of the structure of geochemical (Ag, Pb, Cu, Mo, Zn) and geophysical elds (magnetic eld and magnetic eld gradient) was carried out. The features of the magnetic eld and geochemical elds of copper, zinc, silver, molybdenum and lead were characterized. Based on the statistical approach, processing and interpretation of geochemical and geophysical data was carried out using the ArcGIS software. Statistical analysis of the anomalies showed that in order to identify areas favorable for the localization of gold mineralization according to geochemical and geophysical data, the optimal intervals are as follows: the geochemical eld of molybdenum is 1.38 - 2.65 wt. %; geochemical eld of silver 1.5 - 4.14 wt. %; geochemical eld of copper 1.53 - 7.15 wt. %; zinc geochemical eld 6 .15 - 11.3; geochemical eld of lead 1.0 - 2.2; magnetic eld -5.0 - 5.5 c.u .; magnetic eld gradient 0.01 - 0.35 deg. The data obtained can be used for further exploration work.

For the purpose of monitoring the state of forest ecosystems, it is most effective to use the capabilities 2 of remote sensing methods. Fragments with an area of 990 km (scale 1:10,000) were identi ed on the LANDSAT multispectral satellite images of the territory of the Olyokminsky State Nature Reserve. Then polygons were saved at four levels of detail - 4, 16, 64, 256 with scales of 1:5,000, 1:2,500, 1:1,250, 1:675. When decrypting, an uncontrolled classi cation of polygons was carried out using the ISODATA method (Iterative Self-Organizing Data Analysis Technigue) into 2, 10 classes. Distribution curves of the forest cover index values for polygons of the 4th level of segmentation (detail) were built. The nature of the curves was close to the normal distribution, but the curve for the North polygon was atter, which indicates a more even distribution of the forest cover index over all ranges of values. According to the results of the classi cation into 10 classes, statistic processing was carried out with the calculation of indicators of the difference and similarity of polygons: the variance of the general population and the Fisher test (F-test). There were highlighted the most similar pairs of polygons at different levels of segmentation. The results of changes in the variance of the general population and the F-test at different levels of segmentation are considered. The rules for the transition between four levels of self-similarity (scaling) of multifractal structures are described. It was shown that the variance of the tetrad of each level changes by a constant value when moving between the levels of detail, regardless of the variance values within the tetrad. The value of the transition coef cients in the transition between the levels of segmentation (detail) is the difference between the average values of the variances of each of the levels. The value of the transition coef cients during the transition between the segmentation levels is determined by the difference between the variances of the current and the previous segmentation level.

Since 1972, the geological practice of 2nd year students of the Geological Prospecting Faculty have been conducted at the Tomponsky training ground of the North-Eastern Federal University. Moving to the place of practical training, students can get an idea of the classical frontal structures of the Verkhoyansk fold belt. The main goal of the educational practice is the use of eld observation methods, the compilation of geological maps and the processing of material. Over the 50 years of the land ll’s existence, the drawing up of geological graphics and documentation has undergone signi cant changes. With the advent of specialized information tools, there is a need to improve the educational process of geological survey practice and processing of materials with the help of initially three- dimensional mining and geological information systems. The purpose of our work was to create a three-dimensional wireframe geological model of the Tomponsky training ground as a basis for use by students and teachers for educational and scienti c purposes. To create the model, a classic mapping scheme was used, but using 3D modeling software. The work included the following stages: collection and processing of graphic information; creating a relief surface; digitization of geological boundaries and sections; creation of digital models of surfaces of stratigraphic units; creation of frames of stratigraphic units and tectonic faults. The construction of a virtual geological model of the right bank of the Kurbelyakh River will serve as the basis for testing technological processes that will allow soon to complete the modeling of the entire territory of the Tomponsky training ground of NEFU. The model will be used as a career guidance tool that attracts enrollee interested in obtaining digital competencies in the eld of modeling mineral deposits that are in demand in the mining and geological industry.

Currently, cartography and remote sensing are rapidly developing in connection with the emergence of various modern technologies. GNSS technologies made it possible to determine the location of an object in space with an accuracy of the rst centimeters, unmanned aerial vehicles (UAVs) made it possible to obtain aerial photographs of the area at different times and signi cantly reduced the time spent on eld research, LiDAR made it possible to survey the area with an accuracy of millimeters. In order to monitor geocryological processes on highways, in the summer of 2021, we surveyed areas with a terrestrial based LiDAR (TBL) Trimble TX8 and with UAV a DJI Phantom 4 Adv RTK/PPK. On the investigated sections on the roadbed, subsidence was observed, which form an undulating surface on the road. The reason for the formation of such a surface was the thawing of underground ice and the formation of the formation of subsidence microrelief - byllars. These subsidence landforms have a distinct polygonal pattern. A comparative analysis was carried out in terms of time consumption and shooting accuracy. As the analysis showed, at all stages, the surveying from the TBL took twice as much time. Despite the large time costs, the most important and huge advantage of the TBL over the UAV was the high acquisition accuracy, close to the real values of the relief. Depending on the goals and objectives, these survey methods can be used both individually and in combination, where they perfectly complement each other. At this stage of the study, we received primary data on the surface for the annual monitoring of the roadway subsidence.

Geoinformation technologies are widely used in all spheres of human activity. In a short period, GIS technologies have proven themselves to be a necessary tool for compact data storage and rapid updating of information. In the presented work for the rst time, a web GIS was developed for permafrost conditions on the territory of Yakutia using spatial data and sources (monographs and data of tables). Web GIS is a geoinformation system on the Internet, whose users can view, edit and analyze spatial data using conventional web browsers. The objective of this work was to create a uni ed geocryological database of the Permafrost Institute for the territory of Yakutia. The main tasks that were considered were: to develop the structure of the web GIS database; to determine the programs for working with the database; to assemble a database for the Permafrost Institute; to write code and create a website. The work presented a step-by-step making of a website using PostGIS for storing vector data, program GeoServer using spatial reference data and WMS service, and also presents part of the website code in the JavaScript programming language using open source library the Lea et and a set of tools the Bootstrap. The main results of the research are as follows: the development of the structure of the website with the creation of a spatial database, as well as the collection, systematization of cartographic, attributive, graphic, and textual information with the compilation of GIS with a complex of thematic layers with the attachment of databases on the example of Yakutia.

The article presents studies carried out in the tundra and forest-tundra zones in the Anabar region using remote sensing data and topographic maps. Using topographic maps of 1950 and 1973, modern satellite images Landsat-8, as well as aerial photographs from Google and Esri sources, obtained through the SASPlanet program, we identi ed areas of overgrowth of the tundra with forest. As the climate warms, the forest boundary is shifting further to the north: the tundra is being forced out by the forest, which also mean a change in the permafrost conditions of the territory. Based on the data we obtained during a eld work in the area under consideration, the in uence of the vegetation covers on the depth of the seasonally thawed layer and the ground temperature at the depth of zero annual amplitude of 7-8 m was revealed. So, according to the study results, it was found that the depth of the seasonally thawed layer has the greatest depth in the tundra area, with an increase in forest cover, the seasonally thawed layer decreases, and the ground temperature at the depth of zero annual amplitude, on the contrary, has low values in the tundra, and in the forest-tundra frozen ground above. In the study, the method of thermal infrared survey (radiation temperature) was applied, which, re ecting the landscape conditions of the area (with a certain choice of survey time), can serve as one of the reliable criteria in identifying ground with different permafrost conditions. The interpretation of satellite images based on the differentiation of the surface radiation temperature made it possible to show ground with different permafrost characteristics by landscape types. This article presents the results of the rst stage of the study. Further monitoring studies are planned in the area under consideration.

Using the boreal forests of Central Yakutia as an example, the authors examine the problem of forest res, which became especially vivid in the current year of 2021 and resulted in multibillion-dollar damage not only to the national economy of the Republic of Sakha (Yakutia), but also to Russia as a whole. At the same time, there is a deep genetic connection in the evolution of forest ecosystems and forest res. It is based on the dependence of the stability of ecosystem functioning on the rate of biogeochemical circulation, modulated by forest res. Monitoring forest res is a key link in the study of the causes and patterns of their occurrence and spread. Along with ground observation posts, route and air patrols of forests, modern monitoring of forest res is supported by remote sensing of taiga ecosystems by EOS satellite programs, which have a MODIS spectroradiometer as part of the onboard equipment of the satellite, which provides a high degree of resolution of space imagery.Global warming of the climate and modulation of climate anomalies by cycles of solar activity are considered as the main cause of res. The materials on the rhythm of heat and moisture supply of the climate of Yakutia are given, which determine the cyclicity of dry intervals and, therefore, the frequency of intensi cation of the dynamics of forest res. The geo-geophysical basis for the development of a long-term forecast of natural and climatic anomalies and re hazard in the forests of Central Yakutia is substantiated.

Khangalassky Disctrict of the Sakha Republic (Yakutia) is located in a continental climate zone with very cold long winters, hot short summers, short spring and autumn and large annual temperature amplitudes. Climate changes in Yakutia are manifested, rst of all, in signi cantly increased winter temperatures, frequent cases of atmospheric droughts in summer, changes in the beginning of spring and autumn, changes in the amount and mode of precipitation in all seasons. Global changes in the climate system have led to the fact that the geographical position of the polar front has shifted to the north. The number of cases of southern cyclones entering the territory of Yakutia in winter has increased. In winter, cyclones bring warmer and wetter air, resulting in increased temperatures and precipitation. During the warm period, the position of spring and summer anticyclones changes. In spring and summer, anticyclonic weather can cause atmospheric droughts and, as a result, forest res. In the summer season of 2021, an acute shortage of precipitation combined with extreme temperature anomalies caused the formation of atmospheric droughts in July and August in the Far Eastern Federal District, especially in Yakutia. In the summer of 2021, an extremely large number of forest res was noted in Yakutia. The res have engulfed large areas of the taiga. The authors analyzed the average daily temperature of June-August, took into account the synoptic conditions that caused atmospheric drought. The data from the Isit weather station located at the southern tip of the Lena Pillars National Park were used for the analysis. One of the res, which covered a signi cant area and threatened the village of Kytyl-Dura, operated 40-50 km of the weather station.

The article discusses the main aspects of the evolution of the traditional Yakut calendar against the background of modern climate restructuring In the harsh climate conditions of Yakutia, a calendar of economic activities was especially signi cant for its indigenous population, which was engaged in northern livestock breeding for centuries. With the beginning of the Christianization of the indigenous population of the Lena Territory, and then the Yakut region, which began in the middle of the 17th century, they started using the Orthodox calendar, integrating the church calendar days and holidays into the economic annual cycle of the traditional Yakut calendar. In this work, we used the data from the oldest meteorological station in Yakutsk, analyzed the air temperature with a daily resolution of three winter-spring months (January, February, March), compared the synoptic dates of the folk calendar with the weather in the period from 1901 to 2020. An analysis of long-term meteorological observations of air temperature showed that the weakening of the Asian anticyclone and the increase in the intensity of cyclonic activity, observed since the end of the 1970s and continuing to the present, have led to a softening of winter frosts and a reduction in their duration. As a result, the centuries-old patterns of changes in winter weather in Yakutia, which were established in the Yakut calendar, have now undergone a signi cant transformation. In this regard, the synoptic dates of the traditional Yakut calendar, established by our ancestors during centuries of observation of changes in winter weather, were violated.