It is generally recognized that the formation of the fold-and-thrust tectonic structures of mobile belts on continents is associated with crushing and narrowing of the Earth’s crust as a result of collision of lithospheric plates. The deformation of the Caucasian lithosphere in the neotectonic time is generally consistent with these ideas. However, the block differentiation of the Caucasian lithosphere introduces specific features in the directivity of modern vertical and horizontal movements. In this paper, we analyze vertical movements of the Caucasus estimated by means of high-precision leveling over more than a century and consider their spatial correlation with tectonics, seismicity, stress-strain state, and geophysical fields. A clear relationship indicating the deep tectonic nature of the long-term uplifting of the Caucasus crust is revealed. Due to the differentiation of the Arabian plate movement, the territory of the Caucasus is divided into provinces that differ from each other in the pattern of modern movements, in the orientation of faults, and in the stress-strain state. The seismic regime in these provinces also has differences in the number of seismic events and focal mechanisms of the earthquakes. We propose a model of the deformation mechanism of the Greater Caucasus, which takes into account the long-term trend of the Caucasus uplifting in the conditions of general shortening of the Earth’s crust. The results of the analysis are used as a basis for discussion of a probable mechanism of tectonic evolution of the Greater Caucasus in the neotectonic time, which can be used in the assessment of seismic hazard in the North Caucasus.

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.

Актуальность работы. В статье представлены результаты работ, направленных на развитие сети деформационного ГНСС-мониторинга восточных ветвей Владикавказского разлома на территории Республики Северная Осетия-Алания. Территория республики отличается высокой плотностью геодезических сетей: государственных, научных и коммерческих. Однако представленные ранее исследования не предусматривали использование государственных геодезических пунктов, а также построение на их основе равномерно распределенной по территории республики геодезической сети. Целью исследования, в рамках настоящей статьи, являлось формирование геодезической сети для деформационного ГНСС-мониторинга восточной части и отдельно узла сочленения Восточной и Западной ветвей Владикавказского разлома. Методы исследования. Сформированный полигон основывается на государственных геодезических пунктах, скальных центрах, заложенных коллективом авторов, и пунктах постоянно действующих сетей. Выполнены исследования по совершенствованию методики оценки точности ГНСС-измерений, связанные с особенностями горных физико-географических условий. Методика полевого контроля точностных характеристик комплектов ГНСС-аппаратуры, позволяет без эталонных построений в полевых условиях осуществлять контроль по одиночной базовой линии. Результаты исследования. Важным аспектом является применение методики к новым типам ГНСС-антенн, ранее не исследованных, включая choke-ring, а также антенн китайского производства с китайскими платами CHCNAV, которые в настоящий момент все чаще применяются на территории РФ. Обработка наблюдений по разработанному алгоритму позволила сравнить номинальные параметры ГНСС-антенн с их фактическими характеристиками и учесть фактические положения фазового центра. В сентябре 2023 г. на территории сформированного Осетинского геодинамического полигона выполнен первый цикл наблюдений за СДЗК средствами ГНСС. Первые результаты показали, что основное количество СКО положения пунктов в плане группируется в диапазоне 2–3 мм, а по высоте в диапазоне 3–5 мм. Средние значения СКО в плане и по высоте составили 3 мм и 6 мм соответственно.

Between 2010 and 2016, a series of 11 strong M>6 earthquakes occurred in New Zealand. In the area covering the epicentral zones of these seismic events, the spatiotemporal characteristics of movements and deformations of the Earth’s crust were obtained based on the processing of continuous satellite GPS observations at 64 points of the geodetic network. Using these data, we have studied the evolution of horizontal movements and deformations in order to reveal the possible relationship between the observed deformational and seismic processes. Analysis has been made on the total shear deformation, since the main tectonic structures of the region are faults with a shear mechanism of displacement of their sides. The presence of a giant mantle superplume in the area was the reason for the study of the behavior of horizontal dilatation deformation, and horizontal and vertical crustal motions. Based on the obtained digital deformation models, there were created kinematic visualizations, which are synoptic animations providing direct observations of the seismic deformation process and their heuristic analysis. The study revealed that a series of the strongest earthquakes may be interconnected by a long-term single deformation process, which is caused by the occurrence of an anomalous total shear deformation. The general maximum of shear deformation, dilatation deformation, and horizontal and vertical displacements are concentrated in the center of mantle superplume activity. Prior to strong seismic events, there occur zones of deficit (minimum) displacements of the Earth’s crust in the area of future epicenters, which is of research interest in terms of predicting their locations.

Актуальность работы. В статье представлены результаты работ, направленных на развитие сети деформационного ГНСС-мониторинга восточных ветвей Владикавказского разлома на территории Республики Северная Осетия-Алания. Территория республики отличается высокой плотностью геодезических сетей: государственных, научных и коммерческих. Однако представленные ранее исследования не предусматривали использование государственных геодезических пунктов, а также построение на их основе равномерно распределенной по территории республики геодезической сети. Целью исследования, в рамках настоящей статьи, являлось формирование геодезической сети для деформационного ГНСС-мониторинга восточной части и отдельно узла сочленения Восточной и Западной ветвей Владикавказского разлома. Методы исследования. Сформированный полигон основывается на государственных геодезических пунктах, скальных центрах, заложенных коллективом авторов, и пунктах постоянно действующих сетей. Выполнены исследования по совершенствованию методики оценки точности ГНСС-измерений, связанные с особенностями горных физико-географических условий. Методика полевого контроля точностных характеристик комплектов ГНСС-аппаратуры, позволяет без эталонных построений в полевых условиях осуществлять контроль по одиночной базовой линии. Результаты исследования. Важным аспектом является применение методики к новым типам ГНСС-антенн, ранее не исследованных, включая choke-ring, а также антенн китайского производства с китайскими платами CNCNAV, которые в настоящий момент все чаще применяются на территории РФ. Обработка наблюдений по разработанному алгоритму позволила сравнить номинальные параметры ГНСС-антенн с их фактическими характеристиками и учесть фактические положения фазового центра. В сентябре 2023 г. на территории сформированного Осетинского геодинамического полигона выполнен первый цикл наблюдений за СДЗК средствами ГНСС. Первые результаты показали, что основное количество СКО положения пунктов в плане группируется в диапазоне 2–3 мм, а по высоте в диапазоне 3–5 мм. Средние значения СКО в плане и по высоте составили 3 мм и 6 мм соответственно Relevance. This article presents the results of work aimed at developing a deformation GNSS monitoring network for the eastern branches of the Vladikavkaz Fault in the Republic of North Ossetia-Alania. The region is characterized by a high density of geodetic networks, including state, scientific, and commercial networks. However, previous studies did not incorporate the use of state geodetic points or the establishment of a geodetic network uniformly distributed across the republic. The aim of the study, engineering and geodetic work in forming a geodetic network for deformation GNSS monitoring in the eastern and western branches of the Vladikavkaz fault. Research methods. The formed polygon is based on state geodetic points, rock centers laid by the team of authors, and points of permanent networks. Research was conducted to improve the methodology for assessing the accuracy of GNSS measurements, considering the specific mountain physical and geographical conditions. The field control methodology for GNSS equipment accuracy allows for in-field control using a single baseline without reference constructions. Research results. Similar experiments were previously conducted in flat terrain conditions. An important aspect is the application of the method to new types of GNSS antennas that have not been previously studied, including choke-rings, as well as Chinese-made antennas with Chinese CNCNAV boards, which are currently increasingly used in the Russian Federation. Processing observations using the developed algorithm made it possible to compare the nominal parameters of GNSS antennas with their actual characteristics and take into account the actual positions of the phase center. In September 2023, the first observation cycle for modern crustal movements using GNSS was conducted at the newly established Ossetian geodynamic polygon. The initial results indicated that most of the standard deviations for point positions in plan view were in the range of 2–3 mm, and in height, 3–5 mm. The average standard deviations values in plan view and height were 3 mm and 6 mm, respectively

The study presents the results of the research on geodynamic and geological conditions of the Enisei site (Krasnoyarsk Krai), chosen for the construction of an underground research laboratory. The laboratory is being built at a depth of 500 m to assess the suitability of the rock mass for burying high-level radioactive waste. The rocks consist of weakly fractured gneisses, granites, and dikes of metadolerites. Field observations were conducted on bedrock outcrops. They included the determination of rock mass quality indicators, measurement of rock fracturing, and a rating classification of stability using N.Barton's method. GNSS observations were also made to monitor surface deformations. These data were used to develop a three-dimensional structural model, including lithology, fault disruptions, intrusive bodies, elastic-strength properties of rocks, and the sizes of zones influenced by faulting. It will serve as a basis for boundary conditions and the construction of three-dimensional variational models of stress-strain states, identifying zones of concentration of hazardous stresses, and planning in situ geomechanical experiments in underground mines of the laboratory. The obtained values of the modified QR index for the main types of rocks allowed their classification as stable and moderately stable, corresponding to strong and very strong rocks on Barton's scale and the massif rating according to geomechanical classification.

This paper reports results of mathematical modeling applied to the stress and strain in epicentral zones before and after the large earthquakes that occurred on June 22, 2002 in the Qazvin Province, northwestern Iran (Mw = 6.4) and the Gujarat, India earthquake of January 26, 2001 (M = 6.9). The modeling relied on a method for calculating stress and strain in a blocky elastic isotropic heterogeneous medium disturbed by a set of faults that are due to an external tectonic stress field. The boundary conditions were specified based on geological and seismological data. It has been shown that the epicenters of large crustal earthquakes occur in zones of high stress concentration at the ends of tectonic faults. Rupture occurs when the relationship between acting tectonic stresses satisfies the requirement σyy/σxx >3, thus connecting zones of high stress. The evolution of the aftershock process is controlled by the stress drop caused by a new rupture, while the resulting aftershock clusters are in spatial correlation with the stress drop zone. The new rupture propagates in the direction of dominant tectonic fault orientation in the region. We show a relationship to exist between rupture length and the possible retrospectively predicted location and magnitude of the earthquake depending on the elastic energy buildup and its possible release under specified structural tectonic conditions.

The article presents the following: the results of deformation monitoring by GNSS tools at the FSUE Radon radioactive waste disposal site (Moscow oblast); a brief history of the development of the geodynamic observation network at the industrial site of Radon. the results and geodynamic interpretation of GNSS observations of Earth surface movements for 2008–2017. the results of studies on upgrading Radon’s geodynamic structure, taking into account the creation of a single digital space for the industrial site to manage its lifecycle. The article summarizes the experience in creating life cycle monitoring systems at radioactive waste disposal sites using modern digital measurement methods.

On the territory of the Institute of Physiology of Natural Adaptations, Ural Branch, Russian Academy of Sciences (RAS) (Arkhangelsk oblast), the Geophysical Center (GC) RAS has created a permanent GNSS station as part of the Klimovskaya Integrated Geomagnetic Observatory (KLIM). This article provides a detailed description of the stages of laying and equipping the GNSS complex, describes technological and design solutions, and presents the first results of assessing the quality of the data. After laying the site to study the stability of the geodetic center, test GNSS measurements were organized using a choke ring antenna. To process the measurement results, specialized services were used that implement various strategies for processing static GNSS measurements. The study of time series of increments of coordinates obtained by different services makes it possible to additionally control the quality of GNSS measurements. Observation graphs were built for all three services selected, from which it can be seen that the smallest standard deviation (SD) values and measurement scatter were obtained by the AUSPOS and CSRS-PPP services. A comparison was made of the average annual velocity of the GNSS station of the KLIM with the points of the Svetloe GNSS of the IGS international network. The velocities of horizontal movements are similar to each other in numerical values and directions. Vertical movements often have local and regional causes.

The authors propose a field control of GNSS equipment precision characteristics methodology for recording sub-centimeter movements of the Earth`s surface at geodynamic observations of tectonically moderate areas activity. The factors influencing the accuracy of GNSS measurements are analyzed. The theoretical aspects of developing measuring equipment field control methods are presented. Testing of the devices was carried out in the course of surveys on the Nizhne-Kanskiy massif geodynamic range in Krasnoyarsk krai in 2020–2022. The experiment was made with two-system GNSS facilities of geodesic class (5 to 6 sets). The results show that the proposed methodology of the used tools accuracy characteristics field control enables detecting incorrect nominal parameters of measuring instruments. In this case the parameters of the receivers` antennas are well coordinated with each other. The exactness of control characteristics in plan is at the level of 1,3–2,5 mm, in height – 2,5 mm. It was revealed that the height of the actual phase center of Grant_G3T and MarAnt+ antennas differ from the manufacturer`s declared passport data

There are numerous methods for modeling velocity fields of the Earth’s crust. However, only a few of them are capable of modeling data beyond the contour of the geodetic network (extrapolating). Spatial modeling based on a neural network approach allows for the adequate modeling of the field of recent crustal movements and deformations of the Earth’s crust beyond the geodetic network contour. The study extensively examines the hyperparameter settings and justifies the applicability of the neural network model for predicting crustal movement fields using the Ossetian geodynamic polygon as an example. The presented results, when compared to classical modeling methods, demonstrate that the neural network approach confidently yields results no worse than classical methods. The results of modeling for the Ossetian polygon can be used for geodynamic zoning, identification zones of extension and compression, computing the tectonic component of stresses, and identifying areas of high-gradient displacements.

In 2021, in the Yeniseisky region of the Nizhnekansk Massif in the Krasnoyarsk region, construction of an underground research laboratory (URL) was started to justify safety of high-level radioactive waste disposal. The URL investigations aimed to assess preservation of isolation properties of rock mass exposed to long-active rock pressure, tectonic stresses and heat flow within the whole period of effective radiobiological risk of radioactive waste. Based on the geological data analysis, the structure-and-tectonics model of the Yenisei site was developed, including tectonic faults, lithology, intrusives, as well as heavy fracturing and crushing zones. With no large-scale acquisition of geomechanical data on the Lower Kan Massif, the rock stability was estimated at outcrops on ground surface. The results proved the existing hypotheses of the dynamic impact exerted by the Muratov Fault on the Yenisei site. It was also confirmed that the zone of the dynamic impact of the major faults was less stable than the enclosing rock mass while the rock mass composed of dolerite dykes featured the highest stability.The authors appreciate participation of the researcher from the Nuclear Safety Institute, Russian Academy of Sciences, Candidate of Geological and Mineralogical Sciences O. A. Morozov in this study. This work was conducted in the framework of budgetary funding of the Geophysical Center of RAS, adopted by the Ministry of Science and Higher Education of the Russian Federation.The authors express their gratitude to the students of the NUST MISIS’ College of Mining A. V. Nikitenkova and A. K. Niyaz for the help in processing geological data.

A geodynamic model of the northern part of the Nizhnekanskii massif is presented, developed in connection with the need to assess the safety of the insulating properties of geological formations during the disposal of high-level radioactive waste. The model is based on experimental data from GNSS observations of recent movements of the Earth’s crust, obtained for the period from 2012 to 2021, the results of modeling the stress–strain state, and a systematic analysis of the relationship between deformation processes and tectonic block structures of the region. For an indirect assessment of the insulating properties of a rock mass based on the results of GNSS observations, it was proposed for the first time to use a parameter that characterizes the deficit of horizontal displacements of points of an observation network.

The paper considers geodetic observations focused on modern earth crust movements and rates of its deformations carried out over the period from 2010 to 2022 in the siting area of an underground research facility (URF) in the Nizhnekanskiy rock mass and summarizes their findings. The study demonstrates that the developed GNSS observation method can be used to measure the velocities of modern horizontal movements with a high accuracy at the level of 2.4 mm. It also presents a structural-kinematic model of block movements and deformations, including the spatial layout of areas with maximum velocities of compressive and tensile deformations. The highest rates of horizontal movements were identified in the dynamic influence zone of the Muratov and Pravoberezhniy faults. In general, GNSS observations have shown that the region could be considered geodynamically stable, the maximum strain rates did not exceed 5·10–7 per year. The study also evidences the cyclic nature of the evolving modern movements, which significantly complicates the adoption of a final conclusion on the geodynamic activity of the URF siting region.

In this study, we developed a new approach for feature engineering in geosciences. The main focus of this study was feature engineering based on the implementation of the dynamic activity index (MDAI) as a function of the anomaly of the spatial distribution of data, using systems and discrete mathematical analysis. The methodology for calculating MDAI by groups, geomorphological variability, the density of tectonic faults, stress-strain state, and magnetic field anomalies, is presented herein for a specific area. A detailed analysis of the correlation matrix of MDAI revealed weak correlations between the development features. This showed that the considered properties of the geological environment are independent sets and can be used in the analysis of its geodynamic stability. As a result, it was found that most of the territory where high-level radioactive waste (HLRW) disposal is currently planned is in a relatively stable zone.

The first results of experimental registration of slow deformation waves in the Earth’s crust in connection with the evolution of seismicity at the interface between tectonic plates are presented. The initial data were the time series of changes in the coordinates of continuous GNSS observation stations, earthquake catalogs, and digital maps of the fault tectonics of the region. This paper uses the strategy developed by the authors for creating kinematic visualizations of the seismic-deformation process. Heuristic analysis of the obtained video images made it possibële to detect the phenomena of slow migration of deformations of the Earth’s crust, i.e., deformation waves due to the seismic process and the triggering of strong earthquakes on time intervals of 11 to 15 years.

The Kyushu Island, as well as whole Japanese archipelago, is equipped with dense GPS network (GEONET). It allows us to track the movements and deformations of the earth’s surface over long-term time intervals. In this study, based on daily determinations of the coordinates of GPS stations, analysis has been made on long-term trends in the accumulation of movements and deformations in large areas of the Kyushu Island before the series of April 14–16, 2016 Kumamoto earthquakes to identify deformation precursors and locked, immobile fault zones. The study of the seismic deformation process was performed using the data from 70 continuous permanent GPS stations for the period 2009–2016.The movement and deformation features found characterize the kinematics of the axial zone of the southwestern part of the island arc of the Japanese archipelago. The combination of coseismic compression and uplift in the center of the formed triad of deformation extrema and the consistency between subsidence and extensions at its edges demonstrate the mechanism of growth of the central region of the island arc under compression and the role of volcanism. Of particular interest in the context of the development of movements and deformations during the generation of the Kumamoto earthquakes is the behavior of the minimum displacement moduli of the GNSS sites. Analysis of their kinematics shows the formation of a zone of minimum displacements, in which subsequent strong seismic events were localized. It is shown that rather dense and extensive GNSS networks allow observing and studying the seismic-deformation process at the stages of seismic generation, discharge and relaxation, thereby providing an empirical basis for the development of models for predicting large seismic events.

The paper presents the results from upgrading the satellite geodetic network of the geodynamic test area of the Nizhne-Kansky massif using bedrock pin geodetic centers in 2021–2022. A brief review is given of the historical experience of using bedrock pin centers in developing satellite geodetic networks at geodynamic test sites, in particular, in areas where underground research laboratories are located. Based on this experience, the design and technology of installing rock geodetic centers were developed and implemented. The design of bedrock pin centers makes it possible to minimize the centering error and ensure immobility of GNSS equipment throughout the entire measurement session. The results of expanding the geodetic network in connection with the start of construction of an underground research laboratory in Krasnoyarsk krai are presented. The form of finite elements of the modernized geodetic network is analyzed. It is shown that construction of new GNSS stations had a positive effect on the network geometry. As a result, the network has increased the number of close-to-equilateral triangles (finite elements), which will have a positive effect on the accuracy in calculating the deformations of the Earth’s surface when processing geodetic measurement results and when forecasting the long-term stability of the geological medium in the study area.