Abstract.The article presents the results of medium-scale geological mapping of the Momo-Selennyakh depression. New data on the deep structure, ore and oil-and-gas bearing capacity of the depression were established. Reliable and presumptive signs of oil and gas content were revealed. The geologic structure of the depression, including its location in the Kolyma-Omolon superterrane bordering the Verkhoyansk fold system, was discussed. The Momo-Selennyakh depression is located within the Kolyma-Omolon superterrane, which borders the Verkhoyansk fold system. The depression was formed as a result of crustal stretching in the Late Pliocene – Early Pleistocene. It is composed of sand and gravel deposits of Miocene and Pliocene age overlain by Pleistocene glacial formations. The Selennyakh and Syuryuktyakh depressions are part of the Momo-Selennyakh depression, which is located within the Kolyma-Omolon superterrane. The Selennyakh depression has a gentle shape and is composed of Upper Jurassic sedimentary-volcanogenic formations. The basement of the depression is disrupted by faults along which the blocks moved.
The Syuryuktyakh depression has a more complex structure and is composed of loose sediments of PaleogeneNeogene and Quaternary age. The basement of the depression is composed of Upper Silurian and Devonian carbonate sediments and Upper Jurassic sedimentary-volcanogenic formations. The depression was formed in the zone of the large Ulakhan fault. The results of hydrogeochemical sampling indicate the presence of hidden mineralized crushing zones associated with the Ulakhan fault. These zones have elevated contents of cadmium, boron, copper, zinc, lead, molybdenum and other metals. The presence of bituminous shales, increased content of naphthenic acids, iodine, bromine and fluorine in waters, as well as the presence of oily patches and griffons with gas emission indicate possible oil-bearing capacity of the area.

The article provides an analytical review of the results of direct geochemical studies of the Vilyui syneclise, one of the promising areas for oil and gas in the east of the Siberian Platform. The work objective is to demonstrate the high efficiency of direct geochemical sampling for the search for oil and gas deposits in the conditions of a terrigenous section of the studied territory. It is shown that profile contrast anomalies were identified above productive structures. At the same time, a general increase of light hydrocarbon (LH) components from the flanks to its center and the confinedness of the most noticeable microconcentrations of heavy hydrocarbons (HH) to the periclinal sections of productive structures have been established. Также отмечается пятнистый характер профильных аномалий над продуктивными структурами. This phenomenon, apparently, indicates the predominant effect of filtration migration through various weakened zones from the source of hydrocarbons (deposits). The results of our own reconnaissance work carried out in 2016 on the southern pericline of the Middle-Vilyui gas condensate deposit are presented. The verification work was carried out to evaluate the effectiveness of the equipment and research methods. Relatively high values of benzene and toluene were recorded above the zones of occurrence of deposits T1-IIа and T1-III. It is assumed that the maximum values of B/T can be confined to the zones of oil accumulations. Based on the conducted geochemical samplings and historical experience, it is concluded that in combination with other geological and geophysical methods, direct geochemical studies will increase the reliability of forecasting the prospects of oil and gas potential of poorly studied territories. A recommendation has been made for the use of geochemical samplings in adjacent territories with a similar geological section.

Identification of prospecting geophysical signs of promising areas at the level of ore nodes and fields, deposits and ore structures (ore-localizing structures) has always been one of the main contents of geophysical research. However, especially at the deposit – ore structures level, very often the solution of these tasks becomes very difficult and difficult to implement. The problem is that, in general, rocks in the research area are quite contrasting in their physical properties; however, ore-bearing dike bodies represented by beresitized diorite-porphyrites do not always confidently differ in their physical characteristics from the sandy, carbonaceous, sulfidized and shale sedimentary rocks that contain them. The use of approaches based on statistical processing techniques in the interpretation of geophysical data made it possible to establish geological and geophysical signs of gold-quartz mineralization of the dike type within the study area and thus predict gold mineralization.
The paper presents the results of processing geophysical materials in order to create a list of features characteristic of gold-quartz deposits of the dyke type in the Central-Kolyma region (Magadan Oblast).
The geophysical research complex consisted of electrical profiling and magnetic exploration. MMPOS-2 magnetometers were used to measure the geomagnetic field. The coordinates of the measurement points were determined using a GPS receiver structurally connected to a magnetometer. The methodology of the work provided for the introduction of variations of the geomagnetic field. The variation of the Earth’s magnetic field was taken into account using the SURV software. The work by the electrical profiling method was carried out using an instrument complex: AIE-2 using the median gradient method in modification of induced polarization (SG-VP) at a frequency of 0.3 Hz. Supply line AB=800-900 m, receiving line MN=10 m.
The presented set of works is capable of solving the problems of forecasting gold mineralization in the zone of influence of the Chai-Yurinsky fault of the Yana-Kolyma metallogenic system. Based on the interpretation of the geophysical data, prospecting geological and geophysical signs of gold-quartz mineralization within the ore field are outlined.
One of the promising methodological methods of interpretation in determining the search signs of potentially ore zones is electrical exploration by the method of induced polarization.

A brief overview of the purpose, directions, tasks, and current state of regional geological work on solid minerals is given. The results of the work are summarized, the main directions of the regional study of the subsoil for the medium term are considered in order to increase geological knowledge, solve federal and regional tasks for the study, assessment of the state, management of the state fund of the subsoil in terms of solid mineral resources, planning prospecting based on strategic documents. The innovations of the legislation on subsoil, which come into force on September 01, 2024, concerning the regional geological study of the subsoil, are presented.

Extratropical cyclones over the Sakha Republic (Yakutia) bring rains and reduce the probability of forest fires, but can cause fast rainflood events caused by heavy precipitation. In this study, recurrence of cyclonic events over the Sakha Republic (Yakutia) in summer months between 1950 and 2022 is considered. Recurrence of cyclonic events was defined as the count of cyclone centers over Yakutia or subregions at a standard time of observations. Extratropical cyclone centers database from University of Manitoba (Canada) based on ERA5 reanalysis was used in this study. Cyclonic weather over the territory of the Sakha Republic (Yakutia) persists for 27.5 days on average. The largest count of cyclonic events is noted in the North-Eastern and North-Western sub-regions, while the smallest is in the Southern and Central sub-regions. Across summer months, cyclones are most active in June in all regions except for the Southern sub-region. Here, increased July cyclonic activity is determined by conditions favorable for atmospheric blocking, limited zonal transport promoting the northward intrusion of southern cyclones. There is no pronounced trend in the frequency of occurrence of cyclones except for some regions and months: Western Area, June, increasing; the Sakha Republic (Yakutia), August, decreasing. An absolute minimum in the number of cyclonic events was established for 2019-2021, which, as we believe, was one of the main reasons for the maximum of forest fire activity in the Sakha Republic (Yakutia) observed in these years, along with the Lena River extremely low flows of 2019. An analysis of the circulation conditions leading to such extremes will make it possible to assess the risk of recurrence of similar situations under the future climate.

Within early warning and technological hazards, the need to notify, and to identify, assess and provide the necessary information about the sources of potential hazards is of particular importance. Since there may be causal links between natural and technological disasters, there are increasing concerns that the available knowledge base does not allow for timely warning or relief measures for many hazards.
Any early warning system aims to reduce risk as a measure of potential environmental and economic damage. Such reduction, as a rule, is achieved by continuous study of information on the state of functioning of the naturaltechnical system. Hence the task of systematic collection, accumulation, processing and analysis of information arises. The system of continuous observation, control and analysis of the environmental situation for subsequent diagnosis and forecasting of the state of natural objects is realized within the framework of monitoring, which is performed at three levels – global (planetary), regional and local.
The Sakha Republic (Yakutia) is the largest region of the Russian Federation with a highly concentrated natural-resource potential, providing full-scale projects of national economic development of interregional and federal significance. Yakutia, the area of which is 20 % of Russia’s territory, is a giant natural enclave in geotechnical terms, the administrative boundaries of which cross many geographically heterogeneous ecosystems of seven neighboring territories (administratively independent subjects of ownership). The article considers and reveals the main directions of the early warning system to prevent socio-natural risk as applied to Yakutia, taking into account its natural-territorial uniqueness.

Currently, the absence of a GIS system linked to river basins in Russia may complicate the work of important operational environmental and hydrometeorological surveillance services. It is important to note that simplifying and accelerating the allocation of river basins through open source software can significantly optimize the work of researchers, especially in conditions where it is important to respond promptly to floods and floods in a short time. The purpose of this work is to automate the allocation of river catchment areas, which can help in the study of vast territories of the Far East, as well as contribute to the creation of effective forecasting and monitoring systems. The study presents an automated approach to the identification of watersheds based on the use of geospatial data and information processing algorithms. The presented method demonstrates the effective allocation of watershed boundaries, which makes it possible to simplify the research process and increase the accuracy of the data obtained. The study was conducted within the boundaries of Khangalassky district of the SR(Ya). The data obtained using digital terrain models were corrected, and then used for rapid allocation of watersheds by means of an algorithm developed by the authors. The algorithm is a module for QGIS, which uses the QGIS and GDAL tools in turn, which significantly speeds up the process of creating materials for further research. The results of the study emphasize the accessibility of obtaining information about the geosystems of river basins as integral systems and put forward the prospect of improving GIS processes related to water resources for more effective monitoring of ecosystems and decision-making in the field of environmental protection.

Currently, the scientific community faces the task of identifying and minimizing the negative impact on the natural environment and related environmental risks caused by the impact on ecosystems, especially anthropogenic factors related environmental risks. The determining role in the assessment of environmental risk is to determine the probability of occurrence of effects of different nature in ecosystems because of anthropogenic factors and to take measures to prevent their negative impact. The purpose of the presented theoretical study was to study and analyze the principle of system-wide methodology of quantitative assessment of biogeocenosis quality within the boundaries of anthropogenic influence on the sustainability of industrially developed territory. The considered principle can provide prerequisites for making changes in the norms of nature management in Russia.