Current strain analysis for Obninsk observatory are presented. An extension rate of 5 × 10-9/y was recorded for the central part of European Russia using satellite geodesy. Preliminary results for a new laser extensometer installed in the Obninsk underground gallery (55.12° N, 36.59° E) are presented. The instrument with a 36 m base was an installed at depth of 30 m, along latitude and longitude. In this case, both seismic waves from earthquakes, tidal strain, and long-period signals associated with tectonic processes are recorded. Original strain data presented for July–September 2024 year period. Analysis of record noise is developed. Microseismic waves with periods from 10 to 50 s are presented. The long-period part with periods from 18 to 38 and 291 h connected with meteorological effects. Noise influence was excepted and for tidal analysis of difference strain a 70-day record are used. The Shida tidal parameter is studied. As a result of the study, it is shown that old results by measurements with gravimeters, tube-extensometers, and tiltmeters are related to old elastic tidal models. Our new results show accordance with DDW99 Earth tidal model with viscosity-elastic mantle.
Synchronous recordings of the readings of two torsion pendulums located at a distance of about 3000 km from each other are considered: in the village of Mosrentgen (New Moscow) and Novosibirsk. The duration of joint records is 1140 days, from August 19, 2022, to October 1, 2025. The hypothesis is considered that the excitation of oscillations of torsion pendulums precedes strong seismic events, including those whose epicenters are located far from the location of measurements. The presence of two synchronous measurement points allows you to get rid of the influence of intense local interference. The amplitudes of the envelopes of the Hilbert–Huang expansions of pendulum records for the first 8 levels of decomposition according to empirical modes of oscillation are considered. In successive time windows of 12 h in length, the correlation coefficients between the amplitudes of the envelopes for all levels are calculated and the points of the largest local extrema of the correlations are considered. The sequence of times of occurrence of maximum local correlations between the amplitudes of the envelopes in time windows of length 12 h is analyzed together with the sequence of seismic events with a magnitude of at least 6 using a parametric model of interacting point processes (influence matrix method). The influence matrix method yields a quantitative measure of the influence of two random time sequences on each other. It is shown that the average value of the components of the influence matrices corresponding to the advance of correlation maxima of seismic events is greater than the reverse influence of earthquakes on the synchronous excitation of pendulums, which is evidence of the existence of a precursor effect. An estimate of the variability of the predictor effect in a sliding time window of 1 year was obtained.
This article provides a detailed methodology for studying geological objects using UAVs and subsequent data processing by tectonophysical methods. The strengths of the method and its limitations compared to other practiced approaches are demonstrated. Various software options and their features for image processing and interpretation of results are considered. Particular attention is paid to the use of aerial photography for solving problems of structural geology. The comprehensive methodology for structural and tectonophysical studies using unmanned aerial vehicles (UAVs) represents a modern approach to the detailed analysis of geological structures. The use of UAVs for creating a large-scale, remote analysis of surface relief models increases the volume and accuracy of data about the object by 3 times, as well as the speed of their acquisition in the first months. It reduces distortions to almost 5° and the first centimeters in measurements and assessments obtained during a field survey, and allows significantly enriching databases (by three times or more) for structural-geological and tectonophysical mapping. The methodology covers a wide range of tasks: from regional and urban geological mapping and assessment of engineering risks during construction to monitoring blasting operations and studying the history of rock deformation. This opens up the possibility of studying hard-to-reach or hazardous areas of the Earth and creates conditions for reducing the occupational risks for geologists and engineering workers. The information obtained in this way regarding the tectonic evolution of the object and its geodynamic loading stages allows for a better understanding of the main structural features of the studied objects. Despite its effectiveness in capturing geometry, the method has limitations related to the resolution of the sensors (the impossibility of determining mineral composition at the microlevel) and dependence on weather conditions. These shortcomings are compensated by the mandatory integration of remote sensing data with traditional field structural and tectonophysical studies. Additional limitations of the method include enhanced flight control, high requirements for the processing and submission of documents to obtain flight permits, and the cost of equipment.
In our previously proposed earthquake prediction algorithm Scaling-22, only the earthquake catalog and seismic process self-similarity in a wide energy range are used. However, its implementation is difficult in regions with an insufficient level of catalog representativeness, which includes the Eastern Caucasus. In this regard, in this paper we propose a version of this algorithm adapted to such regions—Scaling-25. Instead of past earthquakes, it uses annual increments of geophysical field parameters closely related to deformation processes in the Earth’s crust. These include high-frequency seismic noise, gravity field, vertical crustal movements, the TAU parameter, and conditionally accumulated seismic energy. Replacing regular observations of geophysical fields with repeated ones at 1-year intervals will significantly reduce their resource intensity.
To address tectonics and geodynamic issues related to the formation of crystalline continental crust, linear folding is studied using field structural geology methods in both hard-copy and digital formats. Using the example of Caledonian fold structures in the Talas Range of the Northern Tien Shan, the results of using several methods for collecting data on the morphology of folded and faulted structures of varying scales are demonstrated. To compile short sections of a structural profile at a scale of 1 : 10 000 to 1 : 1000, conventional measurements of bedding elements (paper techniques) are used in combination with UAV aerial photography of complex areas. UAV photography and multiple digital camera shooting are used to characterize the hinges of large folds with limb widths of up to 0.5 to 1 km. These two types of photographs are transformed using the Agisoft Metashape software into 3D photomodels of these structures, suitable for office study. Multiple photography is also used to study the deformation of minor folds. The resulting description of the structural material at the digital model level is more accurate than recording structures using paper-based technologies, and the material is recorded much more quickly. The results are discussed in relation to the problem of determining the magnitude of shortening for structures of different scales: from “structural cells” (3–5 km along the profile) to small folds measuring a few centimeters.
An approach developed for organizing work with field data on geological stress indicators is described. FaultViz software allows for interactive viewing of a database of field tectonophysical mapping. The procedure for database preparation is described. Specifically developed to optimize the work of structural geologists and tectonophysicists with field data, FaultViz combines elements of the previously developed cataclastic method of Yu.L. Rebetsky and the structural-paragenetic method of L.M. Rastsvetaev. Data management in the program allows for the efficient organization of measurements into samples based on specified parameters (size, kinematics, areal coverage, etc.), significantly accelerating the determination of tectonic stresses using the two aforementioned methods. An illustration of the program’s effectiveness is provided in the article, based on field data from the Western Caucasus and Schmidt Peninsula (Sakhalin Island).
The active Mutnovsky and Gorely volcanoes have been monitored since 1980, when the first seismic station was installed on the slope of Gorely volcano. In 2008, two more stations were deployed: one near Mutnovsky volcano and one on Asacha volcano. However, the system for seismic observation was far from the perfect; with only three stations in the area, the hypocenters of weak volcanic earthquakes were determined with significant error. In 2024, three additional broadband digital seismic stations were installed within the Mutnovsky–Gorely volcano group. Data from these stations are transmitted in real-time to Petropavlovsk-Kamchatsky. This paper provides a detailed discussion of the configuration of the upgraded seismic network, the specifics of the station installations, and their technical specifications. The additional observation points have also enabled the implementation of video monitoring of the volcanic activity of Gorely and Mutnovsky volcanoes, which was previously unfeasible in this area without the presence of digital stations.
The article considers methods of forecasting geogasodynamic phenomena in coal mines based on spectral analysis of acoustic radiation generated into an massif by a functioning working body of mining equipment. The prediction by these methods is possible due to the directly proportional dependence of the sound attenuation coefficient in a solid on the frequency and the inversely proportional dependence on the rock pressure. It is assumed that the amplitude of the signal decreases exponentially with increasing distance from the sound emitter to the seismic receiver. However, experiments have shown that the decrease in amplitude with distance does not occur monotonically. It is suggested that this is due to the interference of different types of waves generated by the source and having different propagation velocities. The results of numerical modeling of the interference of longitudinal and transverse vibrations on the amplitude of the resulting acoustic wave attenuation in a coal and rock massif as it moves away from the source are presented. According to the conditions of the problem, the sound source is represented by linear spectra of seven pairs of longitudinal and transverse waves, each of which has the same frequency and initial amplitude, and zero initial phase. The harmonic frequencies, each of which is the sum of the harmonics of the original spectrum in a window with a width of 200 Hz, have frequencies of the middle of the window of, respectively 100, 300, 500, 700, 900, 1100, and 1300 Hz. As a result of modeling, it was found that due to the different longitudinal and transverse wave velocities at some distances from the source, these oscillations come in phase; as a result, the amplitude of the oscillations is summed up, and at other distances, the oscillations come in antiphase and the resulting amplitude is the result of the difference in the amplitudes of the interfering waves. The numerical experiment confirmed the correctness of the assumption about the interference of wave types as a possible reason for the nonmonotonic decrease in the amplitude of the “noise” of the mining combine with distance from it.
The problem of relative positioning between an alternating magnetic field transmitter and receiver involves determining the position vector between these entities and their mutual orientation. Its relevance stems from the need to enhance the accuracy and reliability of airborne electromagnetic survey data interpretation. This article analyzes the accuracy of solving the relative positioning problem for an electromagnetic field source and receiver. Two key aspects are investigated: first, the imperfection of the transmitter, which is generally not a point dipole; and second, the presence of a response field in the measurements, which is not taken into account when solving the navigation problem. The findings demonstrate that the relative positioning accuracy in a two-dipole field is comparable to that of integrated inertial-satellite navigation systems. The accuracy analysis was conducted using parameters of a modern airborne electromagnetic survey system: EQUATOR.
The aim of the article is to study the specific features of geophysical fields and parameters in the area of a man-made underground water tunnel. Self-potential signals (SP) were measured using nonpolarizing electrodes and and ERA-MAX electrical exploration receiver (SPE ERA, St. Petersburg). The magnetic exploration studies were carried out with MMP-203 proton magnetometer (Geological Exploration plant, Leningrad). Electrotomography was carried out using Skala-48 multielectrode electrical survey equipment (LLC KB Electrometry, Novosibirsk) with the Schlumberger symmetrical survey scheme. The microseismic background was recorded using an OMAR-2s autonomous seismic station (IGF UB RAS, Yekaterinburg). The georadar survey was carried out using SIR-3000 ground penetrating radar and antennas with frequencies 100 and 270 MHz (GSSI, USA). Graphs of magnetic and self-potential fields, electrotomographic and microseismic sections, and a radarogram are presented, which are based on the results of surveys on the research profile. The studies show different levels of the magnetic field and SP in the area of volcanic rocks and gabbro–dolerite dikes. A significant increase in microseismic noise with an increase in weathering crust thickness was observed. Above the underground water tunnel, a local decrease in SP, an anomaly of increased values of electrical resistance values, and intense reflections of radio waves from the top of the tunnel were recorded. The geophysical signs of the boundaries between geological structures and man-made underground objects are revealed. The exact position and depth of the old underground water tunnel have been determined.
The annual dynamics of the microseismic background recorded in 2024–2025 at the Yangibazar Geophysical Research Observatory were analyzed. Spectral (Fourier, PSD) and cross-correlation analyses were performed using data from the Güralp CMG-6TD digital seismometer. Variations of the microseismic background were compared with geomagnetic storms, groundwater level changes, magnetic anomalies, electrotelluric field variations, and electromagnetic impulses. The results demonstrate the sensitivity of the microseismic background to both internal and external geophysical factors. During strong magnetic storms, amplitude increased by 10–15
According to the stick-slip model, the relative movement of the fault faces is an act of unstable slip, in which movement begins after the stresses tangential to the fault plane reach a certain limit. The physical mechanism of dynamic slip along a fault consists of the sequential formation of conglomerates of loaded particles (force chains) in the contact zone and their subsequent destruction. These chains together form a power skeleton, characterized by a certain spatial structure and strength characteristics. An increase in shear stress on the fault banks leads to localized destruction of the power skeleton; further evolution of the system takes the destruction processes to higher spatial levels, which ultimately leads to a shift in the fault banks. Since the development of the process of destruction of force chains in the contact zone of a fault along the hierarchy of scales from bottom to top is similar to the development of fracture formation in a loaded medium from the micro- to the macroscale (sample scale), the authors put forward a hypothesis about the coherent behavior of acoustic noise accompanying the preparation of dynamic slippage and recorded in different areas of the fault zone. This study is tests this hypothesis on a laboratory scale using a setup simulating fault movement. As a result of the analysis, the hypothesis about the synchronization of the statistical properties of acoustic emission during the preparation and implementation of dynamic movement was confirmed. It is shown that the observation (detection) of the synchronization effect of the statistical properties of acoustic emission depends both on the set of parameters for which the spectral measure of coherence is calculated and on the location of recording of the initial data.
The paper presents new data on the age of seismic manifestations in the focal zone of paleoearthquakes on the western wall of the Imandra neotectonic depression (Kola Region, NE Fennoscandian Shield). Detailed paleoseismological studies have been carried out to study unconsolidated sediments and soils in the zone of an active fault structure: the Chuna seismic dislocation. New evidence of Late Pleistocene–Holocene earthquake traces has been found in Quaternary sediments and lacustrine sediments. Based on a combination of methods—isotopic (14C), luminescence (IR-OSL), geomorphological, and correlation—a previously unknown sequence of five events was established: 11.6 ± 0.5, 9.1 ± 0.2, 8.3 ± 0.2, 6.5 ± 0.4, and 2.45 ± 0.35 ka BP (calibrated). It reflects multiple noncoeval activations of the fault and seismic events that occurred in the central Kola Region throughout the Late Glacial and during the Holocene. This made it possible to significantly organize earlier existing information about the timing of paleoearthquakes in the central Kola Region. The results of the study significantly expand and complement paleoseismic catalogs. They reveal new evidence of prehistoric earthquakes in the region and are aimed at reducing the risks of natural destructive processes.
To assess the impact of strong (G4) and extreme (G5) geomagnetic storms observed at the Yangibozor Observatory during 2020–2024 of Solar Cycle 25 on the seismic conditions of Uzbekistan, the number of earthquakes that occurred before and after each storm was compared within time windows of ±2, ±10, and ±30 days relative to the storm onset time for each region. As a result, it was determined that the extreme storm of 10–11 May 2024 and the strong (G4) magnetic storm recorded on 12 August 2024 had an impact on the seismicity of certain regions.
As part of the study, it was established that the majority of recorded signals were the result of technogenic noise; filtering criteria were proposed that are common to the entire acoustic emission (AE) monitoring system. The amplitude and duration of the AE signal were chosen as the filtering parameters, and their compliance with physically justified distributions was chosen as the criterion. At the current stage, this proved insufficient; it became necessary to evaluate the performance and noise levels of individual channels. The results of such an assessment, carried out for different daily recording cycles, are demonstrated by the example of a daily file containing more than 3 mln records. It is shown that one of the most important decisions when setting up an AE system is the choice of frequency filter. It is noted that when using the AE method, one should recall that each control object has its own unique properties.
The study presents a methodological approach to predictive modeling of gold–sulfide mineralization zones in Northern and Central Chukotka using multisensor and multitemporal satellite remote sensing data (Landsat-8, Sentinel-2, ASTER). Spectral analysis methods, including BR, RBD, PCA, and SPCA, were applied to identify hydrothermal–metasomatic alteration. Statistical analysis enabled the selection of thematic layers indicating zones of argillic alteration, phyllic (sericitic) alteration, propylitic alteration, iron oxides/hydroxides, and silicification. Integration of these layers using a fuzzy logic model made it possible to construct a predictive exploration scheme, identify anomalies associated with known ore occurrences and controlling structures, and delineate new, potentially promising areas for gold–sulfide mineralization.
The article presents the results of experiments on reproducing the stick-slip process along a model fault and initiating the movement of the wall of fault by fluid and electric effects. A distinctive feature of the experimental setup used is the extended movable block, which allows for a significant increase in the area of interblock contact filled with dry fine-grained sand. This made it possible to study the spatial pattern of the development of zones of active deformation of the contact zone by solving the problem of locating acoustic emission sources. Particular attention is paid to the response of the contact zone to water injection into it and the direct effect of electric current. As a result of the experimental studies, the spatiotemporal patterns of the response of the model fault to an increase in shear load and fluid and electric effects were determined. It is shown that the effect of electric current causes an increase in acoustic emission activity in the entire area between the electrodes, with the exception of the area of emission activation at the water injection stage. It has been established that electric action can initiate dynamic movement with the activation of spatial areas manifested in the previous stages of action.
The article reviews and summarizes the results of various computational and analytical studies of the seismic (topographic) effect of canyons of different shapes. It is noted that the shape and structure of canyon valleys have a significant effect on the amplitude and frequency characteristics of vibrations of the bottom, walls, and ridges of canyons during seismic wave of different incidence. Based on the published results of various authors on computational modeling of the canyon effect, numerous features of wave fields and effects of amplification and attenuation of seismic vibrations in canyons are shown. The importance of taking into account the results of computational and analytical studies to ensure the seismic-resistant design of construction projects located in and near canyons in seismic zones is emphasized.
Not many studies have been published on the seismicity of Turkmenistan and Northeastern Iran to date. At the same time, some areas of Turkmenistan are characterized by high seismicity along with the most seismically active zones of the former USSR. It is enough to mention the well-known destructive Ashgabat earthquake, which occurred on October 5, 1948. The article compares the distributions of hypocenters of earthquakes in Turkmenistan obtained from the ISC catalog for the period from 1964 to 2021 and results of recalculating hypocenters from the ISC bulletin for the same period. In total, the ISC catalog for the specified period contains about 4800 events with a magnitude greater than 2.5. The authors recalculated hypocenters of about 3700 earthquakes. It is shown that the depths of earthquake sources in the areas under consideration can be located at depths of up to 600 km, while according to the ISC catalog, the maximum focal depths do not exceed 100 km.
The article is devoted to improving the method for predicting seismograms and accelerograms of strong ground movements under the assumption that an earthquake is an instantaneous rupture of the Earth’s crust. The method makes it possible, using the obtained theoretical formulas, to calculate the values of all three ground movement parameters—displacements, velocities, and accelerations—during strong earthquakes with magnitudes of M ≥ 6.0 for general inhomogeneous (multilayer) soil foundations. The article considers cases of inhomogeneous two-layer foundations. The results obtained for 16 variants of heterogeneous two-layer construction sites of categories I–IV based on seismic properties with magnitude M = 7.0 and distance of 15 km from the line of rupture of the predicted earthquake are given as an example. Comparison of the results obtained for real heterogeneous foundations with equivalent homogeneous foundations showed up to 1.3–1.6 times of discrepancies towards an increase, depending on the number of five or three modes of higher oscillations taken into account. Significant influences of various modes of natural oscillations of foundations on the values of displacements and accelerations on the ground surface of a heterogeneous foundations compared to a homogeneous foundation have been revealed. A significant decrease (two or more times) in the rigidity of the upper layer, compared to the rigidity of the lower layer, leads to a significant increase in accelerations on the ground surface. It is recommended that for heterogeneous foundations, the predicted values of displacements and accelerations should be implemented taking into account at least five modes of oscillations of the soil foundation.
