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.

The article discusses deep Earth crustal structure in the Baikal region, neighboring territory and Mongolia. The EIGEN-6C4 satellite gravity model-based Moho depth map was drawn for the territory with coordinates 43 to 61° N, 88 to 120° E. Gravity data interpretation was performed using seismic results obtained. The Bouguer EIGEN-6C4 model data interpretation was performed within the two-layer crust – mantle model with density diference 0.5·103 kg/m3. According to interpretation, Moho depth of the West Siberian Plate and Siberian Platform was estimated at 40–45 km with slight lateral variations, The depth decreases to 34–38 km near the Baikal basins. Strong lateral variations in Moho depth were obtained in mountainous areas south of the boundary going along the Main Sayan fault. The crustal thickness reaches 55–60 km in the area of active orogens (Mongolian Altai, Gobi Altai, Hangai) and decreases to 45 km in the Great Lakes Basin. The Stanovoi Range, Gobi Desert and Big Hingan have Moho depths ranging from 45 to 50 km. The southwesternmost part of the territory near Dzungaria, Tien Shan and Tuffan basin show the maximum drop of Moho from a depth of 40 km to 70 km. The Moho depth estimation error is from 2 to 4 km. The depths obtained for the Central Siberian Plateau and the Baikal basins generally correspond to the seismic data. The ground-based gravity data estimations do not contradict our results. The height anomalies of the quasigeoid model for the EIGEN-6C4 geopotential model relative to the WGS84 ellipsoid are found on the northwestern boundary of the Amur plate. The northern boundary of the Amur plate is clearly defined in the lateral distribution of the Bouguer anomalies and crustal thickness.

Rates of modern movements are an important factor in the modern geodynamics of the Baikal Rift System. Reflection of strong earthquakes in the experimental values of displacements is discussed, as well as the question of modern vertical movements. According to absolute gravimetry and space geodesy measurements of vertical and horizontal movement rates at the Talaya seismic station (Baikal Rift) for 1992–2022, the displacement rates were determined as 1.7–1.9 mm/year SEE with respect to the point of Irkutsk (Siberian Platform). A set of methods was used to obtain the vertical movement rates for different epochs prior to, during, and after the Kultuk earthquake (2008, M = 6.3, 25 km to epicenter). Subsidence rates vary from 1.1 to 3.3 mm/yr. Possible signs of preparation of Baikal earthquakes have been identified

Abstract—An EIGEN-6C4 model for the Altai-Sayan region and northwestern Mongolia constructed using data from satellite gravimetric missions and the results of ground-based measurements with absolute gravimeters and space geodesy receivers is considered. Using the EIGEN-6C4 geopotential (ETOPO1 relief), within the framework of a homogeneous crust model with the involvement of seismic exploration data on the platform part of the study area, an idea was obtained about the changes in the thickness of the earth’s crust in central Asia for the territory extending from 56° to 46° north latitude and from 80° to 100° east longitude, covering Gorny Altai, Kuznetsk Alatau, Western Sayan and Eastern Sayan, Tuva Basin, Tarbagatai Ridge (Kazakhstan), Mongolian Altai (PRC, Mongolia), Great Lakes Basin and Khangai Ridge (Mongolia). Research has shown that the depth of the Mohorovičić boundary increases from the northwest to the southeast of the territory from 40 to 55 km. For the mountainous regions in the south (Mongolian Altai, Khangai Range), the maximum crustal thickness was 55 km. For intermountain valleys and depressions (Tuva Basin, Big Lakes Basin) the depth of the Moho surface is within 45–47 km. In the north, in the flat part of the territory, the thickness of the crust is from 40 to 43 km. The differences between models constructed using gravimetric and seismic data are considered.

More than twenty years of crust motion measurements by space geodesy method include different epochs of Gorny Altai seismic process. Our study aims at investigating the fields of displacement and deformation in the Gorny Altai region, where we have 20 points-net, situated on big territory, from Novosibirsk in North to Molgolian border at South, and from Kazahstan border at West, to Sayan Mountains at East. Chuya earthquake (September, 2003) separated study period (2000‒2022) to several epochs: pre-seismic – 2000‒2003; 2003‒2004 co-seismic period for epicentral zone; 2004‒2013 post-seismic period for epicentral zone and 2000‒2022 period for far-zone without of earthquake influence. Long term data analyses by modern special program. Anomalous behavior features are discovered in the displacement orientations, as well as in the distribution of velocities and deformation in the zone of the future earthquake. The spatial displacement pattern defined for the period of coseismic displacements corresponds to the right‐lateral strike‐slip along the vertical fault. Elastic and viscoelastic models (2D and 3D modification) used for interpretation. Depth of hypocenter was estimated as 14 km with 2 m relative shift on the seismic fault. In frame of two layers model the viscosity of lower crust ranges 5·1019‒1.1·1020 Pa·s for different elastic modulus parameters. The results of our study show that modern horizontal displacements occur in the NNW direction at the rate of 0.8 mm/y for mountain part outside the Chuya earthquake epicenters zone. Velocity of area deformation at mountain part was 2·10–8/y and it is one order more than the value at flat territory situated to North from Gorny Altai.

The work analyzes the connection between a series of Turkish earthquakes in February 2023 and coseismic displacements and deformations on the Earth's surface. In areas of seismic rupture during the five days, there are recordings of three earthquakes on February 6 with magnitudes 7.8, 6.7, 7.5 and then for 5 days period – 42 events of magnitude 4.5–6.0. This work analyzed data obtained by various geodesy methods in the epicentral region. Coseismic effects in a 300 kilometers zone, covering a significant part of the East Anatolian Fault, are considered. Relative displacements up to 6 m have been recorded, with an average value 4 m. When for studying far-field effects, we used GPS network data from 27 international stations, of which seven stations located in Turkey. For the closest to the epicenters of the main aftershock on February 6, 2023, MERS station received coseismic 3D displacements up to 20 mm. The displacement and deformation fields have been constructed according to IGS data. Rates of coseismic deformations in the far zone reach up 10–8 , which is an order of magnitude higher than the background values of 10–9 . Post-seismic horizontal and vertical displacements rates of the Earth's surface in areas of Turkey, located to the southwest of the earthquake epicenters can be associated with floods. A study of displacements rates and deformations of the territory was carried out Turkey and its surroundings in the era of 2017–2023. Highlighted decrease displacement rates two years before seismic activation in 2023. The resulting picture of displacement and deformation rates reflects a current processes in the territory located on the borders of Anatolian Block and tectonic plates: Eurasian, Arabian, and African.

The rates of modern displacements are an important factor in the modern geodynamics of the Baikal rift system. Reflection of strong earthquakes in the experimental values of displacements is still to be discussed, as well as the question of modern vertical movements. According to the measurements of 1992–2022, performed by the methods of absolute gravimetry and space geodesy, the velocities of vertical and horizontal movements at the Talaya seismic station (Baikal Rift). The displacement rates were determined as 1.7 mm/year – 1.9 mm/year at the SEE relative to the Irkutsk point (Siberian platform). A set of methods was used to obtain the vertical velocity val-ues for different epochs, pre-, co- and post-period of Kultuk earthquake (2008, M = 6.3, 25 km to the epicenter). Subsidence rates vary from 1.1 mm/yr to 3.3 mm/yr. Possible signs of the preparation of Baikal earthquakes have been identified.

We discuss the results of gravimetric and satellite geodetic measurements at the Zapolyarnoye and Yamburgskoye gas and oil deposits in Transpolar Western Siberia in subarctic zone of Yamal-Nenets autonomous okrug. The development of mineral deposits and large number of pipelines require monitoring of recent motions of the Earth’s surface. Displacements and other phenomenon were studied by satellite geodesy and absolute gravimetry. It is now possible to obtain the kinematic parameters (rates of subsidence and horizontal motion) and addition information on fluid motion into the layers of the deposits. The ground displacements rate in different short periods recorded at large man-made objects are shown. Rates for hydroobjects are estimated at 5 mm/yr. The gravimetry and satellite geodesy results obtained at the Zapolyarnoye deposit in the northern part of Western Siberia were analyzed. Subsidence rates of 21–23 mm/yr were estimated. An increase in gravity of up to 7 µGal were recorded at the deposits (2006–2008). In this case, the increased gravity is related to surface subsidence (with a normal vertical gradient). Subsidence rates of 16–21 mm/yr were estimated at the Yamburgskoye field. This result is consistent with the rates at Zapolyarnoye. The horizontal rates and orientation differed at different deposits.

Precise gravity measurements at g0·10 -9 level requires taking into account density change, caused by the Earth’s crust deformation and the movement and position of the fluid in the layer. The paper presents analysis of water level observation in three boreholes situated at Primorie, at Kamchatka and at Baikal region. Water-level fluctuations were influenced by earth tides, barometric pressure, co-seismic effects and season precipitations. Water tidal signal was analyzed for calculations of level-strain coefficients, its values changed from 0.1 mm/10-9 to 1.6 mm/10-9. Gravity corrections were developed by volume variation. For borehole drilled at monolithic rock we used the phaselag effect for tidal strain and crack-system orientation was studied in Pribaikalie mountain valley. Longterm gravity results were tested with water level data at Talaya station (Pribaikalie). Talaya gravity point situated at monolithic rock had no influence from water level variation. Level-correction was less than absolute gravity measurement error. Quick coseismic effects of earthquakes are well registered by level measuring, deformation graphical and absolute gravimetric methods.

We describe the history of studying the current crustal movements by various methods and discuss technogenic effects recorded at large water-reservoir zones and mineral deposits in Siberia. Initially, classical surveying techniques aimed to obtain high-accuracy ground-based measurements of height, tilt and direction. Modern geodesy techniques and methods for measuring absolute gravity are now available to investigate displacement, deformation, tilt and other phenomena taking place on the Earth’s surface. These methods are used to estimate kinematic parameters of the crust areas (e.g. rates of subsidence and horizontal movements) and to monitor fluid motions in mineral deposits. Such data are critical for ensuring a proper management of the mineral deposits. In this article, we analyse technogenic processes observed in the Ust Balyk oil-gas field, the Zapolyarny gas deposit, the water-reservoir zone at the Sayano-Shushenskaya hydroelectric power station (SSHPS) on the Yenisei river, and large open-pit mines in the Kuzbass basin. Our analysis is based on surface displacement rates estimated from the data collected in different periods of observations at large man-made facilities. In the study of the hydro technical objects, we estimated the displacement rates at 5.0 mm per year. In the northern areas of the West Siberian petroleum basin, subsidence rates amounted to 20–25 mm per year in the early 2000s. These estimates were supported by the high-accuracy gravity measurements showing an increase up to 6–7 microGal per year in the oil-gas field development areas. We assess a possibility of triggering effects related to weak seismicity due to a high stress accumulation rate (1 KPa per hour) in the SSHPS area. A connection between earth tides and catastrophic events, such as gas emissions in high amounts on mining sites, is discussed. Having analysed the surface monitoring records taken in South Primorye in September 2017, we conclude that underground nuclear explosions in North Korea in this period did not cause any significant displacement of the surface in this most southerly region of the Russian Far East territories.

Adit-based linear strain measurements made with strainmeters 1 to 100 m long allow oscillation processes to be studied in a wide range: from a few tens of hertz to several years. Both seismic waves from earthquakes and long-period oscillatory signals are recorded, related to tectonic processes. The paper describes measurements made with rod and laser strain metering systems in an adit of the Talaya seismic station (coordinates 51.68° N, 103.65° E, Lake Baikal Region). The elastic moduli of rocks were evaluated using strainmeter, microbarograph data, and petrophysical core analysis. The Earth’s integral rheological parameters, through the Earth’s free and tidal oscillations, are calculated. Our findings are in good agreement with modern models of the Earth’s internal structure. The paper describes coseismic and long-term volumetric strain variations induced by large regional earthquakes.

Tidal ocean corrections for gravity observation play an important part in monitoring studies. Tidal ocean models were tested by Transcontinental Tidal Gravity Profile (TTGP) results. This part of the global tidal network was used for study the influence of the Atlantic and Pacific oceans up to coastline. Our tidal result agrees with static theory and had a weak ocean dynamic influence (Schiwiderski and other models) into the center of the Eurasian continent. Near the coast, where ocean effects were strong, the influence increases. In the East part of TTGP, we obtained observation results for Khabarovsk region, for Sakhalin Island and for Primorye region (Sea of Okhotsk and Sea of Japan). In the South part of the Primorye observation (Russian Far East) long-term measurement was completed at the Posyet Bay level station and Cape Shultz gravity station. Based on the results, a selection of ocean tidal models was made and a number of unresolved issues were determined.

Непрерывные измерения геодезическими двухчастотными приемниками космической геодезии на постоянных станциях дают наиболее точный результат по координатам и скоростям смещения.Использование на постоянной станции (NVSK, номер 12319 в сети IGS) приемника TRIMBLE4700 с июля 2000 г. по февраль 2016 г. позволило определить координаты с точностью до долей миллиметра.В результате многолетних GPS-наблюдений определены скорости горизонтальных смещений станции (V N = -1,2 мм/год и V E = 26,3 мм/год).Смещения пунктов соответствуют основным положениям теории тектоники плит.В итоге, выбрана модель вращения Евразийской плиты с координатами полюса Эйлера 54.2°N, 259.3°E и скоростью вращения 0,251 градус/млн лет.С 2016 г. станция переоснащена комплексным приемником ГЛОНАСС-GPS

Laser measurement systems for displacement-deformation measurement have been used usually in geodesy.Investigations of present-day crust deformation are very important for using in spatial and time framework.Experimental laser measurement results collected at Talaya seismology station (Baikal region) presented in this article.Original laser systems have been used for permanent measurements in the underground gallery.Variation of tidal parameters received between 1995 and 2015 was analyzed using regional seismology data for local earthquake (M > 5.5).Anomaly behavior of tidal parameters has been presented for strong earthquakes period.We discuss different models of these effects.Tidal reaction can reach 3 % ÷ 4 % for tidal amplitude and 3° for phase lag, which can be a result of deformed structure and hydrodynamic changes in epicenter earthquake zone, into Main Sayan Fault zone and along Talaya mountainous valley.

Currently, one of the topical issues of improving GLONASS system is modernization of its uniformity measurement equipment, including RF measurement equipment and electronic length measurement equipment. To this end, at the Spatial Reference Proving Ground of theSiberian State University of Geosystems and Technologies (SSUGT), the authors of this article carried out a successful experiment to measure a short GNSS baseline by receivers equipped with Chip Scale Atomic Clocks (CSACs) with instability of 10−11 showed that the mean deviation between the slant distance (D) measured using GNSS receivers connected to CSACs and their certified value varied in the range of 0.1–2.5 mm, with the average value of 0.9 mm. The mean deviation obtained using GNSS geodetic receivers not connected to CSAC and their certified value made up 9.4 mm. The obtained experimental results suggest that substitution of quartz frequency generators with temperature compensation used in geodetic GNSS receivers for Chip Scale Atomic Clocks in any metrological or verification kit increases accuracy and reliability of short baselines measurements results, which highly perspective in view of development of techniques for creating reference baselines with a reproduction error of unit length of about 1 mm per 1 km. The above-mentioned experiment opens up new horizons for the use of Chip Scale Atomic Clocks in such fields of science as metrological support of geodetic equipment, geodesy, etc.

The modern gravimetry methods are capable of measuring gravity with an accuracy of up to 10–10 of the normal value, which is commensurate with the accuracy of the up-to-date methods of displacement measurements by satellite geodesy. Significant changes, e.g., in the coseismic displacements of the Earth’s surface are recorded in the zones of large earthquakes. These changes should manifest themselves in the variations of gravity. Absolute measurements have been conducted by various modifications of absolute ballistic gravimeters GABL since the mid-1970s at the Klyuchi point (Novosibirsk) in the south of the West Siberian plate. Monitoring observations have been taking place in the seismically active regions since the 1990s. In this paper we consider the results of the long-term measurements of the variations in gravity and recent crustal displacements for different types of earthquakes (the zones of shear, extension, and compression). In the seismically active areas in the east of Russia, the longest annual series of absolute measurements starting from 1992 was recorded in the southeastern segment of Baikal region. In this area, the Kultuk earthquake with magnitude 6.5 occurred on August 27, 2008, at a distance of 25 km from the observation point of the Talaya seismic station. The measurements in Gornyi (Mountainous) Altai have been conducted since 2000. A strikeslip earthquake with magnitude 7.5 took place in the southern segment of the region on September 27, 2003. The effects of the catastrophic M = 9.0 Tohoku, Japan, earthquake of March 11, 2011 were identified in Primor’e in the far zone of the event. The empirical data are consistent with the results of modeling based on the seismological data. The coseismic variations in gravity are caused by the combined effect of the changes in the elevation of the observation point and crustal deformation.

The paper is focused on different kinds of gravity results obtained in Shults Cape Observatory for 2010–2015. Gravity observation is interpreted together with GPS observation data which was obtained from 2012 to 2015 at the same station. The station is situated on Gamov peninsular (42.58° N, 131.15° E, Russia) at the coast of Japan Sea. This region constitutes the eastern boundary of Eurasia. This major continental tectonic feature is associated with a seismic activity, high heat flow and anomalous thickness of earth's crust. The goal of the observation was the investigation of gravity variation with time and seismicity situation monitoring. Gravity observation was developed at special basement by absolute gravimeter (GABL type) and by spring gravimeter (SCINREX CG-5and gPhone type). Tidal models were tested by results of observation with spring gravimeters. Reduction task was solved, as the experimental data received from different points of Shults Cape Observatory was used. Applied reduction coefficient is 203.3 μGal m−1, and agrees with theoretical calculation. Next goal was studying structure of earth's crust by means of gravity models. Gravity anomaly varied from 30 mGal to 46 mGal, which also depend on difference reference system. Experimental results were used for testing of the structure of continental boundary, which also depends on the sea bottom flexion. Thickness of elastic layer was estimated from 12 km to 18 km by using different models.

Seismic method is usually used for elastic parametric estimation. This is why this method presents dynamic parameters of Earth. Frequency seismic range changes greatly from geodynamic modelling time. Now we have opportunity to use geodesy result for some years for elastic parameters estimation. Static solution from elastic theory may be used for the interpretation of long term results. It presents static elastic parameter. The inverse problem for different types of vertical surface loading on one year period is calculated. Two cases of loading with maximal and minimal area are presented. Results are determined by space geodesy and leveling methods. Current relation between atmospheric pressure and vertical displacements was estimated at the center of Siberian Anti Cyclone with size varied from 2000 km to 3000 km. Pressure-displacement coefficients (PDC) can be achieved by three years observation (0.997 mm/mbar for NVSK GPS station). It is used for elastic module study of geology medium with maximum thickness up to 600 km. In the context of elastic model, the modulus of rigidity is estimated to be 113 GPa. Vast expanse of anti-cyclone may relate with rheology of crust and upper mantle. Smaller size of surface loading – local loading is seasonal variation of water reservoir. Annual vertical changes were obtained by leveling near the dam of the reservoir. PDC ratio was 1.15 mm/bar for these places. In elastic theory, the Young modulus E = 80 GPa (Poisson ratio = 0.25, the modulus of rigidity = 32 GPa) was calculated by sixteen years of leveling measurements. This result can effectively be represented for upper crust. Our results were checked by solution for coseismic displacement of Chyia-Altai earthquake (Sep. 27, 2003, M = 7.3). Coseismic results calculated by static modules agree with experimental coseismic GPS data at 10% level.

Analysis of geological and geophysical data on the boundary zones between the Eurasian plate and other plates shows poor knowledge of the deep structure of the region. This information will help to refine the position of the plate boundaries and the structure of the Earth’s crust and mantle. We present data on the seismicity and deep structure along the deep seismic sounding (DSS) profile running across the boundary between the Eurasian and Okhotsk plates. A comprehensive analysis of the DSS materials and seismic data shows a significant expression of this boundary zone both in the deep Earth’s crust structures and in the Moho. A zone of anomalous seismicity and deep structure extends along the DSS profile for several hundred kilometers. We have refined the position of the main boundary between the Eurasian and Okhotsk plates, which passes approximately along 144° E.

This work presents the results of the measurements of absolute gravity value g obtained over four field seasons in 2010–2013 at marine expeditionary station of Pacific Oceanological Institute at Shults Cape of Gamov peninsular (42.58° N, 131.15° E, Russia). The measurements revealed that during the first year the absolute g at the measurement point increased by 5.1 μGal, and during the second year, by 3.2 μGal. The auxiliary point No. 2 located 46 m below the main point No. 1 was founded in 2012 to create a gravimetric test site for calibration of the tidal gravimeter g-Phone.