Geofizicheskiy Zhurnal

Learning from the experience of anniversary self-service.

N.P. Mikhailova — Wed, 24 Jun 2026 00:00:00 +0300

In this article, the author shares memories of her life and scientific journey on the eve of her 100th anniversary, which falls in 2026. She recounts the history of her family, her childhood during World War II, her choice of profession, and her subsequent studies. Considerable attention is given to her many years of work at the Institute of Geophysics, the development of paleomagnetic research in Ukraine, international cooperation, and the colleagues who accompanied her along the way.

Warmest congratulations to the highly esteemed Ninel Petrovna Mikhailova on the occasion of her 100th birthday

V.I. Starostenko — Wed, 24 Jun 2026 00:00:00 +0300

April 23, 2026 Ninel Petrovna Mikhailova turned 100 years old!

Igor Ivanovich Rokityansky Turns 95

V.I. Starostenko — Wed, 24 Jun 2026 00:00:00 +0300

The article is dedicated to the 95th anniversary of the internationally renowned geophysicist Igor Ivanovich Rokityansky, who made a significant contribution to the study of the electrical conductivity of the Earth's crust and upper mantle. During his many years of work at the Institute of Geophysics of the NAS of Ukraine, he co-discovered the coastal effect, introduced the term "geoelectromagnetic investigations," and published a fundamental monograph with the prestigious Springer publishing house. In addition to classical geophysical methods, the scientist also explored alternative physical concepts, in particular Kozyrev's asymmetric mechanics, and devoted considerable attention to the training of highly qualified scientific personnel.

In memory of the renowned geologist Boris Fedorovich Zernetsky

V.I. Starostenko, V.P. Kobolev — Wed, 24 Jun 2026 00:00:00 +0300

The article outlines the life and scientific career of the prominent Ukrainian scientist, Doctor of Geological and Mineralogical Sciences Borys Fedorovych Zernetsky (1929–2026), who dedicated his work to the geology of seas and oceans. He was one of the pioneers of marine geological research at the NAS of Ukraine, participating in numerous expeditions across the World Ocean, including two circumnavigations, and made a significant contribution to the study of bottom sediments and Cenozoic paleontology. The scientist was also known as a talented popularizer of science and an educator, leaving behind a substantial scientific legacy and fond memories among his colleagues.

The Poltava Gravimetric Observatory Turns 100

O.V. Legostaeva, V.I. Starostenko — Wed, 24 Jun 2026 00:00:00 +0300

In 2026, the Poltava Gravimetric Observatory of the S.I. Subbotin Institute of Geophysics of the NAS of Ukraine will celebrate its 100th anniversary, which is a landmark event for the development of national and global Earth sciences. Founded in 1926 by the prominent scientist Alexander Orlov, the institution played a key role in creating the gravimetric map of Ukraine, exploring mineral resources, and formally proving the existence of the Earth's liquid core. Over the past century, the observatory has significantly expanded its research areas, encompassing studies of the deep structure of the Earth's crust, radio astronomical observations using "URAN-2" telescopes, satellite geodesy, and the monitoring of local seismic activity. Despite the modern challenges of war, the observatory remains a symbol of the resilience of academic science, successfully combining fundamental research with the practical monitoring of natural and anthropogenic processes.

The 100th anniversary of the Poltava Gravimetric Observatory: past and present

M.V. Lubkov, V.G. Pavlyk, L.Ya. Halyavina, R.V. Vachishyn, M.F. Tyshuk — Wed, 24 Jun 2026 00:00:00 +0300

To the centenary of the Poltava Gravimetric Observatory of the S.I. Subbotin Institute of Geophysics of the NAS of Ukraine, an extended historical opus is presented on the expediency of the founding the scientific institution, its tasks, main stages of development, and main scientific achievements in the past and in our time. The observatory is one of the oldest scientific institutions of astronomical and geophysical specialization in Ukraine; on April 7, 2026 it celebrated its 100th anniversary. The observatory was created on the initiative of the outstanding astronomer and geophysicist academician O.Ya. Orlov, who headed it in 1926—1934 and 1938—1951. At the beginning, its main task was to conduct a survey and create a gravimetric map of Ukraine in order to realize its natural resource potential. This great work was successfully carried out by a relatively small team of employees of the Observatory in 1938. On the other hand, O.Ya. Orlov is rightfully considered one of the founders of modern geodynamics. Being a scientist of high erudition in the fields of astronomy, geodesy, geophysics, and seismology, O.Ya. Orlov consistently, especially during the Poltava period of his activity, introduced a comprehensive study of the Earth as a planet based on the methods of the specified disciplines. His innovative ideas and original methods were embodied and developed in the Observatory by the scientist himself and his outstanding students — E.P. Fedorov, Z.M. Aksentieva, M.A. Popov, and other scientists. The period 1938—1961 in the scientific activity of the observatory in the field of astronomic-geodynamic and geophysical research can be without exaggeration called an era of great achievements. At the current stage of the development of the Poltava Gravimetric Observatory, its main tasks are the continuation of fundamental and applied scientific research in the field of astronomy, geodynamics, geophysics, geotectonics, and oil and gas production in order to obtain new scientific knowledge and use it for scientific and practical purposes in the national economy of Ukraine.

Study of the influence of meteorological factors on the parameters of the main tidal waves in the NS direction

Andrii Kutnyi, Volodymyr Pavlyk, Bogdan Kutnyi, Tetiana Babych — Wed, 24 Jun 2026 00:00:00 +0300

In order to identify the influence of meteorological factors on the parameters of the main tidal waves of tilt, which have important geophysical significance, hourly series of 11-year tiltmeter observations in Poltava for the NS direction and similar 10-year series of air temperature and atmospheric pressure were processed by tidal harmonic analysis. Significant systematic disturbances of the parameters of the main tidal waves and the phase delay of the daily disturbing tilt of the ground in relation to the air temperature were revealed, which in January—March is 3 hours, and in May—December — 6 hours. It was established that the causes of systematic disturbances of the tidal parameters are deformation processes of the soil layer at a depth of 0.10—0.25 m, which are caused by local exogenous and endogenous factors, among which the main role is played by the instability of the thermal field, soil moisture and the length of thermal waves in the vicinity of the tiltmeter point. The possibility of freeing the parameters of daily tidal waves from systematic temperature disturbances by involving the theory of thermoelastic deformations, physical properties of the soil, and temperature field parameters is shown. Thus, for the K1 wave, the difference in amplitudes and phase shifts between the temperature perturbing tilts obtained from observations and those calculated on the basis of the theory of thermoelastic deformations turned out to be practically absent in the average annual measurement. This convincingly indicates the possibility and necessity of cleaning the observed data from the systematic influence of temperature disturbances in order to obtain reliable geophysical information. It was established that atmospheric pressure practically does not affect the parameters of semidiurnal and diurnal tidal waves of lunar origin. The obtained results convincingly indicate the influence of atmospheric pressure on both the amplitude and the phase of the tidal wave of solar origin S2.

The 100th anniversary of the Poltava Gravimetric Observatory: from subtle Earth tides to seismic-tidal technology

Volodymyr Shliakhovyi, Ruslan Shyian — Wed, 24 Jun 2026 00:00:00 +0300

The study of solid Earth tides is a fundamental method for investigating Earth’s internal structure, enabling analysis of geodynamic processes in the lithosphere, mantle, core, and atmosphere. Over a century of advancements in tidal observation techniques has brought forth the development of equipment characterized by ultra-high resolution and sensitivity. Modern instrumental observations are also used to monitor the geodynamic state of the environment, including its local and regional geostructures. They play a significant role in monitoring deformation regimes and assessing the structural stability of critical geotechnical infrastructure.

Experimental and theoretical investigations of Earth tide phenomena have been a primary research focus of the Poltava Gravimetric Observatory of the IGPH NASU since its inception in 1926. The research program encompasses astronomical, tiltmetric, gravimetric, and extensometric observations. Studies conducted in the first half of the 20th century not only successfully confirmed Earth tides as a real geophysical phenomenon but also established them as a fundamental source of scientific information regarding the Earth’s structure and internal processes. Between 1960 and 1990, the deployment of advanced equipment facilitated tidal studies at more than 40 stations in Ukraine, yielding extensive datasets for geodynamic analysis. Throughout its century-long history, the Poltava Gravimetric Observatory has made substantial contributions to the field of Earth tide research and the advancement of related technologies. This includes integrating Earth-tidal and seismic methods, which can serve not only fundamental research but also address critical practical challenges, such as monitoring the geological environment and the stability of mine workings and bridge structures, and investigating caving processes in mines.

Local vertical movements of the ground surface based on the results of 18-year extensometric observations in Poltava

Volodymyr Pavlyk, Andriy Kutnyi, Mykola Zalyvadnyi, Tetiana Babych — Wed, 24 Jun 2026 00:00:00 +0300

The results of 18-year observations of the vertical component of local ground surface dynamics using a quartz extensometer of the Poltava Gravimetric Observatory are presented. The instrument is installed at a geodynamic polygon in Poltava and allows monitoring of vertical displacements of the soil layer at a depth of 0.5 m from the surface with an accuracy of 10^-6 m in order to study the influence of external factors of hydrometeorological origin on the dynamics of the most mobile upper soil layer. It was established that the dominant component of vertical movements is the seasonal component with an average annual amplitude of 1.726±0.045 mm, the moment of maximum elevation of the ground, which falls on 114.32 ±0.06 days from the beginning of the year (April 24) and a period of 364.42±0.30 days. Depending on the climatic features of a particular year of observations, the magnitude of periodic local vertical displacements varies from 1.0 mm to 5.5 mm, and the moments of maximum elevation of the ground occur in the period from March 28 to May 16. Seasonal vertical movements are primarily caused by periodic variations in the moisture of medium loamy soils of the polygon. If the soil moisture exceeds its maximum molecular moisture capacity, this factor ceases to act on vertical movements. Fluctuations in groundwater levels are not the cause of vertical movements, although they occur in phase with them. It is shown that the abnormally dry summer of 2024 in Poltava caused the lowest vertical position of the ground surface for the entire observation period. Ignoring vertical movements of hydrometeorological origin can lead to incorrect interpretation of the results of the study of tectonic and technogenic deformations of the ground surface.

Ballistic Gravimeter of the Poltava Gravimetric Observatory. History of Creation and Modernization

O.I. Khalyavin, L.Ya. Khalyavina — Wed, 24 Jun 2026 00:00:00 +0300

Development of the ballistic gravimeter began at the Poltava Gravimetric Observatory in 1968. After the first prototype was tested in 1972, it was updated further. Lead engineer B.I. Brodsky supervised the work. A highly qualified mechanic, V.A. Ovchinnikov, made significant contributions to the project. By 2000, a working BG-2 prototype had been built; it was equipped with an advanced measurement recording and processing system. Since 2003, regular measurements of the gravity acceleration g had been conducted. The accuracy of these measurements was inferior to that of commercial instruments, prompting continued work on improving BG-2’s key components. Despite the limited accuracy of the results, analysis of a 7-year g data series showed the presence of tidal waves, in particular the semidiurnal lunar M2 wave, demonstrating the feasibility of using the equipment for gravity monitoring.

BG-2 resumed operation in 2024. The mechanical and optical units remained unchanged. The control, recording, and measurement processing module was modernized. It is based on an STM32F407VGT6 programmable microcontroller (MCU) (SYSCLC=168 MHz), integrated into the STM32F4-DISCOVERY board, as well an OSC5A2B02 10 MHz temperature-stabilized oscillator for MCU clocking. The MCU’s internal timer polling intervals are monitored. Software for processing measurements and analyzing the obtained results was developed. Trial measurements verified the module’s functionality

Study of acid-base balance in the soil-groundwater system

O.A. Khakhel, T.P. Romashko — Wed, 24 Jun 2026 00:00:00 +0300

The interaction between pH-buffer systems of soil and groundwater may play a role in shaping the hydrogeochemical conditions that affect pH stability in these two environments. Despite extensive studies of soil and groundwater, the related behavior of these systems remains poorly understood, especially under conditions of spatial heterogeneity and anthropogenic influence. This study aims to investigate the interaction between soil pH-buffering mechanisms and groundwater chemistry, focusing on identifying the dominant processes governing pH regulation. We measured pH, total alkalinity, calcium ion concentrations, and components of the carbonate buffer system. Soil and groundwater exhibited an interrelated buffering mechanism. pH stabilization in the studied system was controlled by the combined effect of multiple buffering mechanisms, including mineral equilibria, ion exchange, and solution-phase reactions. These processes operated in a coupled manner and were influenced by hydrodynamic conditions and local environmental factors. A conceptual model of «collective buffering action» is proposed to describe the integrated effect of interacting buffering processes, whereby soils and groundwater function as an integrated acid-base system. The model is intended as a qualitative framework rather than a fully quantitative representation. Three phases of buffer interaction between soil and groundwater were identified, ranging from background equilibrium to developed alkalization or acidification, with opposite or synchronized shifts in the pH of soil and groundwater depending on the phase. This mechanism can give early warnings of acid-base disturbances and has practical implications for hydrological environmental monitoring.

Geodynamic modeling of geoid changes and true polar migration in the geological past using spherical harmonic analysis

A.L. Tserklevych, T.B. Badlo, Ye.O. Shylo, I.V. Volos , B.I. Shchur — Wed, 24 Jun 2026 00:00:00 +0300

The results of paleogeoid reconstruction for different Phanerozoic (0—540 million years) geological epochs using spherical harmonic analysis are presented. The method is based on an assumption of the relative stability of the relationship between topography and geoid over geological time for low- and medium-degree of spherical harmonics. The basis for this assumption is that most of the geoid topography (about 9/10) must originate from inhomogeneities in the distribution of subcrustal density, which are more stable in geological time. Knowing the modern relationship between topography and the geoid and having reconstructions of paleotopography, it is possible to estimate the ancient shape of the geoid by removing the contribution of the modern topography of the lithosphere to the heights of the geoid and reconstructing the geoid (paleogeoid) based on paleo-reconstructions of topography in past geological periods. We used modern models of the geoid EGM2008, topography ETOPO1, and paleotopographic reconstructions PaleoDEM. An algorithm is proposed that includes determining the transfer function between topography and geoid, removing the influence of modern topography, and restoring the paleogeoid based on reconstructed paleotopography. The modeling results demonstrate that the main contribution to the formation of the global geoid (about 90 %) is due the mantle density inhomogeneities to depths of ~1000 km, while the contribution of surface topography is secondary. Analysis of second-order harmonic coefficients allowed us to reconstruct the trajectory of the Earth’s rotational pole migration, with a maximum deviation of about 2600 m during the Phanerozoic. The results are consistent with current ideas about the dominant role of mantle convection in shaping the Earth’s global figure and confirm the connection between tectonic processes, mass redistribution, and changes in the planet’s inertia tensor.

Monitoring and assessment of earth surface deformation due to the gravitative influence of the Moon and the Sun in geodynamically different zones of Kyiv and Kryvyi Rih

Wed, 24 Jun 2026 00:00:00 +0300

Human activities such as mineral extraction in the Kryvyi Rih region, have significantly altered the geological environment, affecting soil stability and creating additional risks for buildings, infrastructure, and urban facilities. A comparable process of environmental destabilization occurred much earlier in the Kyiv Pechersk Lavra area, where historical architectural structures and cultural monuments were also influenced by changes in the geological environment. Although these processes occurred in different centuries and were driven by distinct historical and economic factors, their consequences exhibit similar patterns. In both regions, cracks of varying severity, localized ground subsidence, and gradual displacement of buildings toward zones containing underground cavities—both natural and man-made—have been documented.

This study employs high-precision laser inclinometers of a Ukrainian design which detect small angular deformations of the ground surface and allow the analysis of factors contributing to slope instability and soil movement in areas with pronounced surface gradients and complex morphology.

Two identical laser inclinometers were installed for experimental monitoring: one in Kyiv and one in Kryvyi Rih. One instrument is certified by the State Enterprise «UKRMETRTESTSTANDARD» and meets modern national standards of accuracy, providing reliable data on soil displacement. Results indicate that lunar—solar tidal forces may influence the stability of shallow soil layers, particularly in regions with significant surface gradients and subsurface voids.

These findings demonstrate the considerable potential of laser inclinometer monitoring for investigating geodynamic processes, assessing deformation risks, predicting hazardous ground movements, and improving urban safety in areas with complex surface morphology and underground cavities.