Vol 24, No 1 (2024)

The study of current sedimentation processes and radioactive contamination in the total area of the Don Delta is the research goal. The presented paper contains data analysis of radioecological and lithologic studies on bottom sediments, sampled in the northern part of the Don Delta in 2022. Based on the research results obtained, the authors provide the characteristics of the current conditions of sedimentation and specific activity of artificial and natural radionuclides in fluvial deposits, as well as indicate that similar in characteristics sandy-silty aleurites and sandy aleurite-clayish silts with inclusions of plant and shell detritus compose the bottom sediments of numerous braided channels. The authors determined the zonal accumulation character of both 137Cs technogenic and 226Ra, 40K, and 232Th natural radionuclides which conditions their accumulation and content increase from the lower delta to the upper delta areas. The velocity of currents in the braided channels (bayous) and related sedimentation conditions of suspended matter, as well as the lithotype of the bottom ground determine the indicated regularity. We assume that unlike 137Cs the distribution of natural radionuclides (40K, 226Ra, and 232Th) mainly depends on the mineral content of sediments entering the delta with the river runoff. Relatively low indices – on average ca. 9 Bq/kg of dry weight (d.w.) – characterise the current range of 137Cs radioisotope concentrations in the sediments of the Northern Don Delta. Such a level of specific activity is of no danger to the regional ecosystem.

Geoinformatics is a scientific discipline that focuses on natural, technical, and socioeconomic spatial systems studied through computer modeling of localized objects and phenomena. The main goals of geoinformatics as a science are visualization, localization, and decision-making regarding spatial transformations of the environment. The structure of geoinformatics includes such sections as geosystem modeling, spatial analysis, and applied geoinformatics itself. The development of technologies for collecting, storing, converting and exchanging spatial and temporal data has led to the rapid development of GIS technologies and the emergence of a wide variety of industrial GIS aimed at processing geodata in order to make informed decisions. Currently, geoinformatics in many industries is perceived as a geoinformation industry, which implies the presence of its own equipment, the development of commercial software products such as GIS, a staff of experienced expert analysts and the organization of marketing. The paper highlights three of the most pressing problems faced by researchers in the field of geoinformatics over the past two decades: interoperability, digital transformation, and geodata fusion. The characteristic features of these problems and some aspects of their solution are considered.

For the first time, the results of modern studies of the earth's crust based on gravity data from the GOCE satellite Project are used for a comparative regional metallogenic analysis of the geodynamic settings of the formation of polymetallic deposits in Western Europe and the Mediterranean segment of the Tethys belt. It is shown that exhalative sulfide deposits (SEDEX) and cuprous sandstones and shales (SSC) are mainly located in the earth's crust with a predominant development of the lower “basalt” layer of the earth's crust. Pyrite copper and lead-zinc deposits in volcanogenic rocks (VMS), as well as some occurrences of the SEDEX type, are found in supra-subduction island-arc and accretionary crustal settings with a predominant development of the middle “granite” layer. Lead-zinc ores of the Mississippi type (MVT) are localized in deep pericratonic sedimentary basins with petroleum-bearing specialization on the shelf and continental slope, regardless of the stratification of the earth's crust. The results obtained can be used for regional forecasting and metallogenic constructions, prospecting and assessment of new deposits.

Placer deposits had (and for a number of components still have) an important role in providing strategic types of mineral resource base for both Russia and the world as a whole. Placers have a number of advantages that make them in demand by the mining industry: relatively shallow (often accessible for open-pit mining) occurrence, disintegrated state of productive deposits, simplicity of enrichment processes (mainly gravitational systems), as well as the possibility of rapid involvement in exploitation, which significantly reduces payback period for investments. All this is even more relevant for modern Russia, when, in the shortest possible time, in conditions of a shortage of credit resources, it is necessary to implement a program of import substitution and provide the country with scarce types of strategic mineral raw materials, such as gold, platinum group metals, tin, rare metals, titanium, chromium, diamonds.

The space physicists and the earthquake (EQ) prediction community exploit the same instruments – magnetometers, but for different tasks: space physicists try to comprehend the global electrodynamics of near-Earth space on various time scales, whereas the seismic community develops electromagnetic methods of short-term EQ prediction. The lack of deep collaboration between those communities may result sometimes in erroneous conclusions. In this critical review, we demonstrate some incorrect results caused by a neglect of specifics of geomagnetic field evolution during space weather activation. The considered examples comprise: Magnetic storms as a trigger of EQs; ULF waves as a global EQ precursor; Geomagnetic impulses before seismic shocks; Long-period geomagnetic disturbances generated by strong EQs; Discrimination of underground ULF sources by amplitude-phase gradients; Depression of ULF power as a short-term EQ precursor; and Detection of seimogenic emissions by satellites. To verify the reliability of the above widely disseminated results data from available arrays of fluxgate and search-coil magnetometers have been re-analyzed. In all considered events, the “anomalous” geomagnetic field behavior can be explained by global geomagnetic activity, and it is apparently not associated with seismic activity. This critical review does not claim that ULF electromagnetic field cannot be used as a sensitive indicator of the EQ preparation processes, but we suggest that both communities must cooperate their studies more tightly using data exchange, combined usage of magnetometer networks, organization of CDAW for unique events, etc.

This paper is devoted to the review of currently functioning seismological agencies, seismic monitoring networks created, developed and supported by them, as well as earthquake catalogs produced. Particular attention is focused on international and national seismological centers and seismic networks. A historical insight about the first observations made by seismic networks completes the picture. The basic parameters of the main seismic networks and the principles of functioning for seismological centers are considered. The key characteristics of seismic catalogs that determine the criteria for their quality are discussed. The system-analytical approach to solving the urgent problem of creating the most complete and representative earthquake catalogs with a unified magnitude scale by integrating data from international, national and regional catalogs in the studied region is presented.