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Modern satellite positioning and navigation technologies are not applicable in specific areas such as the exploration of oil and gas deposits by means of directional drilling techniques. Here, we can rely solely on natural geophysical fields, such as the Earth's magnetic field. The precise underground navigation of borehole drilling instruments requires a seamless, near-real-time access to operational geomagnetic data. This paper describes the MAGNUS BD hardware-software system, deployed at the Geophysical Center of the Russian Academy of Sciences, that provides the efficient accumulation, storage, and processing of geomagnetic data. This system, based on the Big Data (BD) technology, is a modern successor of the MAGNUS processing software complex developed in 2016. MAGNUS BD represents one of the first cases of the BD technology's application to geomagnetic data. Its implementation provided a significant increase in the speed of information processing and allowed for the use of high-frequency geomagnetic satellite data and expanding the overall functionality of the system. During the MAGNUS BD system's deployment on a physically separate dedicated cluster, the existing classical database (DB) was migrated to the Arenadata database with full preservation of its functionality. This paper gives a brief analysis of the current problems of directional drilling geomagnetic support and outlines the possible solutions using the MAGNUS BD system. [ABSTRACT FROM AUTHOR]

This paper analyzes and reviews the rapid uplifts of the Earth's crust in the Caucasus that occurred over the last century. The uplifts were registered by precise repeated state leveling and reflected on officially published maps of vertical movements of the Earth's crust. This study summarizes information on the region's vertical movements over more than a century. The present study describes the technology for creating maps of recent vertical movements of the Earth's crust using precision leveling data. This paper summarizes cases of recording uplifts of the Earth's surface in other regions of the world in connection with seismic activity. The authors carried out intercomparison of vertical movements with tectonics, seismicity, and geophysical fields, which discovered their apparent mutual correspondence. This indicates the deep tectonic nature of the observed uplifts of the Earth's crust. Spatial and temporal agreement with the distribution of strong earthquakes showed a natural relationship. It has been shown that strong earthquakes are confined to the boundaries of zones of rapid uplift. They occur predominantly in areas of transition between uplifts and subsidence. The results obtained demonstrate the role of the study and observations of vertical movements of the Caucasus in assessing periods and areas of increased seismic hazard. [ABSTRACT FROM AUTHOR]

This article is the continuation of a study by authors to create the most complete and representative earthquake catalogs with a unified magnitude scale. The catalog created of the Ossetian sector of the Greater Caucasus (the territory of the Republic of North Ossetia–Alania and adjacent areas) was formed by the aggregation of all available data from Soviet, modern Russian, and Georgian catalogs, as well as the data from the International Seismological Centre. The integration was carried out using the author's approach based on the modified nearest neighbor method. The integrated catalog of the Ossetian sector of the Greater Caucasus contains 16,285 events for the period 1962–2022. For all events, magnitude estimates are reduced to a unified "proxy-MW" scale. The integration of data from various sources made it possible to significantly replenish the beginning of the aftershock sequence of the Racha earthquake with MW = 7.0, which occurred on 29 April 1991. There has been a change in the level of registration over time. Thus, there is a significant lack of events for the periods 1967–1970 and 1988–1991; starting from 1995, the catalog is complete for magnitude 3.2, and since 2005 for magnitude 2.2. The integration of Soviet and modern Russian and Georgian catalogs made it possible to significantly increase the completeness and representativeness of seismic events in the studied Ossetian sector of the Greater Caucasus. This once again demonstrates both the fundamental importance of merging seismic data from global, national, and regional catalogs and the effectiveness of the author's developed method. [ABSTRACT FROM AUTHOR]

This paper represents the final part of a series of studies aimed at creating the most reliable and representative earthquake catalog covering the Russian and European Arctic. The earthquake catalog of the Gakkel and Knipovich ridges, as well as the Svalbard Archipelago with a unified magnitude scale, was formed based on the combination of four regional Russian catalogs and the ISC catalog. The merging of catalogs was carried out using the modification of the author's methodology, which allowed for the identification of records in different datasets related to the same seismic event. The modification was introduced due to significant changes over time in the source catalogs. The unified proxy moment magnitude scale was formed based on regression analysis of the different magnitude estimates provided by various agencies. The integrated catalog included 17,922 earthquakes that occurred during the period 1962–2022. Analysis of the integrated catalog showed that the level of registration in the studied area significantly varies over space and time. Before 1995, the catalog contained only strong and moderate earthquakes, and the magnitude of complete registration Mc was 5.0 in the Gakkel Ridge, 4.7 in the Knipovich Ridge, and 4.5 in the Svalbard Archipelago. The number of recorded events increased in the period 1995–2011, and Mc decreased to 4.0 in the Gakkel and Knipovich ridges and to 2.8 in the Svalbard Archipelago. The best level of registration in the Svalbard Archipelago and the Knipovich Ridge was achieved after 2012, when Mc reached 1.7 and 2.8, respectively. In the Gakkel Ridge, despite a noticeable increase in the number of reported events from 2012, the magnitude of complete registration did not improve and was 4.0. The presented integrated earthquake catalog is intended for a wide range of studies of the seismic regime of the Arctic. [ABSTRACT FROM AUTHOR]

The article is a continuation of the research on creating the most complete and representative earthquake catalogs by combining all available data from regional, national, and international seismological agencies and reducing magnitudes to a uniform scale. The task of identifying and removing duplicates that arise during the merging process is solved using the authors' modification of the nearest neighbor method. It is evident that the intelligent merging of different earthquake catalogs for the same territory will improve the completeness and representativeness of events in the final integrated catalog. In this article, the earthquake catalog of the western sector of the Arctic zone of the Russian Federation (AZRF) covering the period 1962–2022 was created by merging three regional Russian catalogs and the ISC catalog. The ratio of magnitude types in the catalog for different seismic networks was analyzed, and magnitude estimates were unified based on the obtained ratios. For analyzing seismic activity in the western AZRF, it is recommended to use earthquakes from the period 1998–2020 when the catalog was significantly cleaned from explosions and other events of the "non-earthquake" type. [ABSTRACT FROM AUTHOR]

A method for the combined processing measurements of the projections and the absolute magnitudes of geomagnetic field intensity vectors, based on mathematical technology of local approximation models, was proposed. The approach realized in this paper, based on the proposed method, provides the increase of accuracy of the measurements of the projections of the geomagnetic intensity vector. An algorithm for the two-stage combined processing of the measurements of projections and absolute magnitudes of geomagnetic field intensity vectors was developed. The operation of the combined processing algorithm was tested on models and observatory measurements. The estimates of the combined processing algorithm errors were obtained using statistical modelling. The reduction of the root mean square error values was achieved for the estimates of the projections of geomagnetic field intensity vectors. [ABSTRACT FROM AUTHOR]