The article presents the general results of medium- and long-term earthquake forecasting with K ≥ 13 (M ≥ 5.0) in the Baikal rift zone. They were obtained in recent years through the joint use of the Prediction geoinformation system and the developed two-stage phenomenological model for the periods of preshock preparation of earthquakes. This model was created based on the analysis of seismological data on the preparation of the most dangerous local earthquakes that occurred in the Baikal rift zone. It is consistent with results obtained in the study of seismic regimes of ice shock preparation on the ice cover of Lake Baikal and in conducting field experiments on fault sections with the aim of clarifying the physical and mechanical conditions for the emergence of sources of seismic-range wave-oscillation generation. The paper provides an example of practical use of the obtained results of earthquake forecasting, as well as methods of clarifying seismic-hazard assessments in relation to infrastructure in the city of Angarsk, located 100 km from the seismically dangerous Main Sayan Fault (MSF), in the zone of which, during the analysis of the seismic regime, a “locked” segment with a seismic gap was identified. In accordance with its linear dimensions with a length of 60 km, according to two assumed equations of relationships L/M, estimates of energy potential were calculated, the maximum values of which correspond to the values Mmax = 7.1 and 7.8. It is shown that the use of the obtained earthquake-forecast results helps to clarify the level of seismic hazard for the nearest time intervals of expectation of earthquakes with different values Mmax. An example of assessing the current seismic hazard using a medium-term forecast for the infrastructure of the city of Angarsk is considered for possible seismic tremors from the south-eastern section of the MSF zone for the next 10 and 50 years. When compared with the OSR-16 map, it is shown that the calculations carried out indicate a relatively lower level of seismic hazard for the city of Angarsk, with waiting times of 10 and 50 years.

Using the developed geoinformation system “Prediction”, an analysis was made of information available from the media on two devastating earthquakes in the Türkiye that occurred in the western segment of the East Anatolian fault on February 6, 2023. The possibilities of recognizing signs of the preparation of earthquake data by means of medium-term forecasting developed for the Baikal rift zone, which are important for assessing seismic hazard and seismic risk, are discussed. Based on the analysis of the consequences of the large-scale destruction of residential and industrial infrastructure in the Türkiye, the causes of the huge damage to the country's economy caused by earthquakes, which are largely due to unfavorable seismotectonic conditions and urbanization problems that arose as a result of insufficient compliance with the necessary requirements and norms of earthquake-resistant construction, are considered.

The methods developed by the world community to date to withstand strong natural and induced destructive earthquakes do not effectively reduce material losses and the number of victims. The authors propose for discussion an integrated approach to solving the problem of ensuring seismic safety, based on the use of new important information about the geological conditions for earthquake generation. This involved the use of results of numerical and physical modeling, as well as physical full-scale experiments in the natural fault areas. The paper analyzes the petrophysical conditions of deep-seated frictional processes in coseismic faults, revealed through detailed studies of the fragments of paleoearthquake centers that became accessible after their exhumation from seismic-focal depths of the Earth’s crust. The collected information allowed the authors to clarify with a high degree of certainty the origin and occurrence of seismic motions. This paper presents briefly the results of the medium-term forecast of earthquakes with M≥5.0 as applied to the seismodynamic regime of the Baikal rift zone. The forecast emphasizes the detection of places for 1–11-year earthquake generation cycles. A comprehensive analysis of the collected information made it possible to substantiate the conclusion about an opportunity to prevent earthquake damage by using hydrodynamic damping of seismically hazardous fault segments. In the last section, consideration is being given to one of the most promising methods of such man-made impacts, which uses modern technological advances in drilling deep multil-branch and directionally inclined wells with horizontal deviation. The paper discusses the techniques that make it possible to prevent episodes of unexpected reactivation of fault segments in the form of excitation of earthquakes with M≥6.0. Attention is drawn to conducting tests at selected sites in order to improve the technology as part of the approach to earthquake damping.

This article solves the task of selecting and describing methods for assessing the social and economic indicators of seismic risk using the example of the town of Angarsk in Irkutsk oblast, which is located dangerously close (100–120 km) to seismically dangerous faults in the Eastern Sayan uplift and the Baikal Rift Zone characterized by magnitudes M = 6.5–8.0. The relevance of the study is determined by the demand for clarifying the seismicity of an actively developing region and the declaration of the Sendai Framework for Disaster Risk Reduction 2015–2030, which calls for improving risk assessment methods and implementing measures to mitigate it. The goal is to obtain reliable estimates of risk indicators that are necessary and sufficient for making the decision to mitigate. The scientific novelty is due to the fact that, for the first time, as part of one work for a single town, the results of all stages of the study are presented, including updating the assessment of seismic hazard, the vulnerability of risk elements, and the calculation of various indicators of possible damage associated with the risk. In addition, a joint analysis of all values has been performed for the first time. To assess the risk indicators, methods of computer simulation using the GIS Extremum, developed with the participation of the authors of this paper, were applied. In addition to describing methodological techniques, the article provides a rationale for the parameters of the possible and most dangerous seismic events. For the town of Angarsk, these are 8 and 9 grades of the MMSK-86 scale. An assessment of the social and economic indicators of seismic risk has been performed, the values of which are the highest in the microdistricts of Baikalsk, Staro-Baikalsk, Kitoy, and Novy-4, which implies the need for special measures, including the inspection and strengthening of the seismic resistance of buildings.

Abstract—A joint analysis of seismicity in the Baikal Rift Zone (BRZ) is carried out using modern instrumental data (Baikal Branch of the Federal Research Center “Geophysical Survey of the Russian Academy of Sciences,” 1963–2021) combined together with historical and paleoseismological data on earthquakes. The structure of the seismicity field within BRZ is studied by the new statistical methods. The spatial resolution in the seismically active areas attained 100–120 km. The analysis revealed patches of seismic activity alternating with areas of relative seismic quiescence (seismic gaps). The seismic patches form a hierarchical structure. At the highest level (a spatial scale of 500–1800 km and a lifetime of 300 years and longer), three main patches of seismicity are identified within BRZ, defining the Sayan, Baikal, and Severomuiskii (North Muya) subregions. Smaller patches form a structure with a spatial scale of 100–500 km and a lifetime of 50–200 years. The patches of seismic activity reflect the segmentation of active faults during the seismotectonic evolution of the Earth crust. The estimates of the maximum regional magnitude Mmax from instrumental data for 1963–2021 and from seismogeological data are compared. It is shown that quantile estimates Qq(T) of the maximum earthquakes in the future time interval T are preferable to the Mmax estimates for the seismic risk problems.

The paper discusses the basic principles underlying a new approach to the control of seismic activity in tectonic fault zones. A key component of the approach is the use of controlled man-made impacts on highly stressed fault segments. The applicability of the approach was verified in field experiments on seismically active fault segments of the Baikal rift zone and collision structures of Mongolia. The paper reports the most striking examples of applying man-made pulsed vibrational impacts to highly stressed fault segments in combination with controlled fluid injection into deep wells. The results of impacts on the studied fault segments are discussed in the light of new geological data on physicochemical processes in the zones of ancient seismically active faults and recent advances in deep drilling for hydrocarbon exploration and production. A justification is provided for the concept of controlled shear stress relaxation in potentially hazardous fault segments showing the signs of earthquake preparation. The possible implementation of the proposed concept in the near future is discussed.

We discuss the relationship of solar activity with the seismicity of Earth and reasons for the differences in the results of studies of various authors. Using the epoch superposition method, we analyze the differences in seismic activity distribution over phases of the 11-year solar cycle for the whole world, hemispheres, sectors, latitudinal belts, and individual regions. The northeastern sector of Earth has been shown to make the main contribution to the planetary distribution of seismic activity over phases of the 11-year solar cycle. We have revealed a pattern in the distribution of seismic activity over latitudinal belts: the solar cycle phases, at which the main maximum of seismic activity occurs, increase with increasing latitude in both hemispheres. For some regions, the results may differ from the generalized results for Earth due to the influence of local geodynamic conditions during the destruction of the earth's crust. In middle latitudes, the maximum number of earthquakes is shifted to the later phases of the solar cycle from west to east, which was not found for the northern regions. We discuss possible reasons for various manifestations of solar-terrestrial relationships for different regions, taking into account their different structure and geodynamic development modes. The presence of pronounced maxima of the seismic activity distribution over the 11-year solar cycle phases allows us to use them for refining the “time” parameter in the medium-term prediction of dangerous earthquakes.

The paper summarizes the results of long-term field research in the dynamics of the Baikal ice cover as a multiscale block medium similar to the lithosphere in structure, rheology, and seismotectonic features. The analysis covers data on deformation, seismicity, and contact interaction modes as well as on meteorological factors responsible for dynamic fracture of ice plates and strong ice shocks with earthquake-like vibrations. Similarity between seismic features in ice interface zones and zones of tectonic subduction, collision, and shear is discussed. Reasoning from dynamic analogies and similarities of destruction processes in the ice and lithosphere, the research data can help solving fundamental and applied problems, particularly those of earthquake prediction and assessment of contact interactions between lithospheric plates in fault zones.

The paper briefly overviews the evolution of ideas concerning causes and mechanisms related to the origin of the Baikal rift zone (BRZ) in the centre of the Eurasian plate, discusses parameters of the recent seismogeodynamic impact on the seismotectonic regime in BRZ due to the Western Pacific subduction and the Indo-Eurasian collision, and attempts at estimating their contributions to the modern geodynamics of rifting processes in Pribaikalie. Seismic migration processes and specific density patterns of the released seismic energy are analyzed for two selected profiles between BRZ and the regions of collision and subduction. A statistical method is proposed to calculate seismic migration from space-time diagrams, and equations are developed to show a decrease in specific density of seismic energy released in the lithosphere at a distance from the interplate boundaries towards the Baikal rift. The modern geodynamic impact on the seismotectonic regime in BRZ due to the Indo-Eurasian collision is reflected in moderate horizontal compression of the lithosphere, mainly in the southwestern BRZ and partly in the central BRZ. In the transition area in this profile, the specific density of released seismic energy is about 1.72×1010 J/km2. The geodynamic impact on the seismotectonic regime in BRZ from the subduction zone (from the Nankai trough) is shown by a significantly lower specific density of released seismic energy, 1.02×1010 J/km2. In the lithosphere of the northeastern BRZ, a weaker geodynamic influence is mainly manifested by responses to strong seismic events and earthquake focal mechanisms with a clear strike-slip component in the Chara and Tokka basins located in the Aldan shield of the Siberian platform.We discuss a possible mechanism that drives the propagation of the geodynamic impact on BRZ from the interplate contact areas. In our opinion, the geodynamic influence propagates intermittently in the lithospheric plates due to motions of slow-deformation-wave fronts, which are reflected in the diagrams as seismic activity clusters. The longrange propagation of slow waves is realized through triggering of active faults in the lithosphere. Such faults interacting with slow wave deformations may be manifested as excited sources of dissipation of seismic oscillations resulting from a spontaneous release of the energy accumulated in the Earth interior. This mechanism of endogenous energy supply may explain the observed propagation of recordable slow elastoplastic deformations for many thousands of kilometres.Today, when the new materials are available to show more ancient ages of the early elements of BRZ, and it is established that the tectonic energy is reduced with distance from the interplate boundaries, there is no support for the hypothesis based on the role of the Indo-Eurasian collision in the formation of BRZ. A recordable seismotectonic impact on the seismic regime in BRZ can occasionally occur after a major seismic activity in the regions of collision and subduction. This phenomenon may be used as a criterion for developing medium-term earthquake predictions, taking into account a delay in response.Short-term cycles observed in the seismic regime of BRZ and its adjacent areas, as well as in the seismic migration processes are considered as a basis for making a conclusion that seismotectonic processes associated with interactions between the plates, as well as the seismic migration processes may be impacted by a potential modulating influence of cosmogenic factors. Such extraterrestrial factors include short-term variations in the Earth’s rotation and orbiting modes, as well as in gravitational interactions between the Earth, Sun and Moon. It is unlikely that the shortterm cycles may result from the slow endogenous processes of thermal convection in the Earth.

Seismicity migration is studied by a new method based on space-time diagrams and a combination of cluster and regression analyses. Data from the global and Baikal regional earthquake catalogues are analysed with the application of the specially designed geographic information system (GIS) in order to establish parameters and mechanisms of seismicity migration in space and time. We study the migration of seismic events in the following geostructural systems: the Baikal rift zone (BRZ), the area between BRZ and the Indo-Eurasian interplatecollision zone, the area between BRZ and the West-Pacific seismic foci Benoiff zone, and two segments of the Middle Atlantic ridge.As evidenced by the obtained results, studying regimes of seismic migration provides for analyses of space-time distribution of seismic energy in the fault-block structure of the lithosphere and facilitates more detailed studies of the origin of deformation waves and mechanisms of the seismotectonic regime of the Earth. Forward (from the equator) and backward (towards the equator) migration of seismic events are established in all the regions under study. It is assumed that this phenomenon may result from regular changes of the polar compression of the Earth due to variations of its rotation regime. Besides, it is revealed that energy clusters of migration are regularly generated, and the regularity may be related to the 11-year cycle of the solar activity which impacts the seismic regime. We discuss the need to study the interference of wave deformations in the lithosphere which are initiated by several external energy sources. It is proposed to consider the regimes of planetary seismicity migration as a reflection of redistribution of endogenic (primarily heat) energy of the Earth during the destruction of its lithospheric shell under the impacts of cosmogenic factors via triggering mechansms. With reference to our positive experiences of applying the proposed concept to BRZ, we consider possibilities of using the seismicity migration data for prediction of earthquakes in the planetary and regional scales.

Long-term research in the preparation of earthquakes of different energies with M = 3.5-7.9 within the Baikal rift zones shows that they are similar to each other and to microquakes with E = 1-10(3) J initiated on tectonic fault fragments in natural experiments. Moreover, detailed studies of slickensides of dimensions 1-10(3) m(2) in tectonic faults also demonstrate their physicomechanical similarity to each other and to nano-and microscale contact patches of different materials in laboratory experiments. The research results confirm the conclusion that there exists a similarity in the laws of contact interaction of different solids, including their stick-to-dynamic slip transition, from nanoscopic to geodynamic scales.

A series of full-scale experiments was performed to study the influence of impact loads on the parameters of seismic vibrations initiated in variable friction. The study was conducted on a test setup Tribo which is a movable concrete slab modeling an allochthon on a rough plane of the Angara fault segment in Baikal region. Contact interactions of asperities in the slip zone were recorded using strain and load measuring equipment and four seismic stations Baykal-7HR widely used for recording earthquakes. The proposed physical modeling method and obtained results can be of interest for the development of new physical models of differently scaled sources of seismic energy dissipation in tectonic faults and can be useful for seismological studies, related data interpretation, and improvement of extended forecast of rock bursts and earthquakes.

The main challenge in the prediction of tectonic earthquakes and their control is still insufficient awareness of seismotectonic processes in the lithosphere and upper mantle during the preparation of strong earthquakes. This is associated in many respects with not quite appropriate equipment for researchers. Among relevant problems is also a lack of adequate models of preparation of earthquake sources at different stages, and this retards the development of earthquake prediction methods. The paper discusses long-term research on deformation and destruction of the Baikal ice cover in the context of physical mesomechanics. With certain combinations of meteorological factors (wind, temperature, precipitation, undercurrents, etc.) responsible for deformation, major cracks of many kilometers arise in the Baikal ice cover. Their spontaneous growth often involves seismic phenomena as ice quakes whose energy reaches E max = 104–107 J. The nucleation of major cracks is similar to that of rock bursts of moderate strength or weak earthquakes. It is found that ice quakes and earthquakes are both preceded by foreshocks, seismic calm for tens of minutes, aftershocks and other events against the background of accelerated creep in fractures and increased seismoacoustic activity. Research data make it possible to put forward two genetically interrelated criteria among basic factors for ice quake prediction: variations in deformation modes at convergent boundaries of ice sheets and a specific intensification mode-generation of strong foreshocks in a segment in which ice sheets are prepared for dynamic motion. We substantiate the conclusion that simpler and clearer scenarios of preparation of strong seismic events in the Baikal ice cover allow successful physical simulation of preparation of tectonic earthquakes and rock bursts and advances in their prediction. We also consider and substantiate the feasibility of techniques for more efficient seismic risk reduction.

The level of within-and among-population variation of larch inhabiting the range of Larix olgensis A. Henry in Primorye was estimated on the basis of 440 RAPD loci identified by means of 12 random primers. In ten populations examined, the proportion of polymorphic loci was 35–60%, the average expected heterozygosity varied from 0.1340 to 0.2169, and the average gene flow estimate was 1.38. According to Fisher’s test for heterogeneity, the pairwise differences of the fragment frequencies between the populations were statistically significant. The subdivision index G ST = 0.2663 indicated that the interpopulation variation component accounted for approximately 27% of the total variation. Coefficients of Nei’s genetic distance between the populations varied from 0.0137 to 0.0934. Most of the samples with high support clustered according to the geographic positions relative to one another within the range. These results suggest that the populations examined are characterized by high genetic variation, like the larch populations of Siberia and the Russian Far East studied earlier, but, in contrast to the latter, exhibit higher among-population variability.

Genetic diversity of larches from six geographically distant regions, Tomsk, Irkutsk, Ulan-Ude (Siberia), and Blagoveshchensk, Khabarovsk, Yuzhno-Sakhalinsk (Far East) was examined by means of RAPD analysis. Tree DNA samples were compared using 457 RAPD loci (97% of which were polymorphic), identified with 17 primers of random sequences. In the samples examined, 32 to 49% of the genes were in heterozygous state, mean expected heterozygosity (Hexp) varied from 0.1373 to 0.1891, and the genetic distances (DN) for different sample pairs varied from 0.0361 to 0.1802. The main population parameters were determined for Larix sibirica Ledeb., L. gmelinii(Rupr.) Rupr., and L. kamtschatica (Rupr.) Carr. Analysis of the genetic relationships showed that L. kamtschatica was characterized by highest genetic differentiation from the other larches examined, while larches from Primorskii krai were genetically close toL. sibirica.

Genetic diversity of larches from six geographically isolated regions, Tomsk, Irkutsk, Ulan-Ude (Siberia), and Blagoveshchensk, Khabarovsk, Yuzhno-Sakhalinsk (Far East) was examined by means of RAPD analysis. Tree DNA samples were compared using 457 RAPD loci (97% of which were polymorphic), identified with 17 primers of random sequences. In the samples examined, 32 to 49% of the genes were in heterozygous state, mean expected heterozygosity (Hexp) varied from 0.1373 to 0.1891, and the genetic distances (DN) for different sample pairs varied from 0.0361 to 0.1802. The main population parameters were determined for Larix sibirica Ledeb., L. gmelinni (Rupr.) Rupr., and L. kamtschatica (Rupr.) Carr. Analysis of the genetic relationships showed that L. kamtschatica was characterized by highest genetic differentiation from the other larches examined, while larches from Primorskii krai were genetically close to L. sibirica.

The Bayesian approach is used to estimate main seismic parameters: M-max - maximum possible regional magnitude; lambda - seismic-activity rate; and b - slope of the plot for the magnitude frequency law. The suggested method allows one to use catalogs with varying lower magnitude completeness threshold as well as historical catalogs. The quantiles of M-max(T) are estimated, where M-max(T) is the maximum magnitude of an earthquake that will occur in a future time interval T. Also, the magnitude uncertainties (standard deviations) are established. The method is applied to estimate M-max and M-max(T) in Baikal Rift Zone. This estimation gives M-max = = 8.07 +/- 0.47.