Geofizicheskiy Zhurnal

Material depth models of the Ukrainian Shield

2025-06-24T13:10:44+03:00

Deep composition models have been constructed by the method of petrophysical thermobaric modeling for individual megablocks of the Ukrainian Shield. The method is intended for comparison the data of deep seismic sounding and experimental study of physical parameters at high pressures and temperatures of rock samples that form the studied megablocks. The validity of regional deep thermobaric petrophysical constructions is confirmed by the existence of appropriate criteria of similarity. With petrophysical thermobaric modeling, the equality of average values of pressure values and temperatures in laboratory and natural conditions is enough to accept them comparable. This basic principle is at the heart of the method. The second principle of the petrophysical thermobaric modeling is based on the differentiation of physical parameters of various mineral environments, depending on their petrological characteristics, including composition, genesis, structural and textural features, and other factors. Individual РT protocols of experiments were developed for each studied area of the Ukrainian Shield.

Within the Ukrainian Shield, it has been established that the Earth’s crust is usually composed of granite-gneisses underlain by rocks of intermediate composition (charnockitoides, enderbites or diorites) and, then, down to the Moho interface, by mafic rocks (mafic granulites, gabroides) and ultra-mafic (рyroxenitеs) rock соmposition. All models record low velocity zones (zones of thermobaric decompaction of rocks) usually located at depths of 5—15 km. The predicted of such zones correspond to the intervals experimentally detected seismic wave inversions and densities of the studied rock samples of the Ukrainian Shield depending on the pressure and temperature according to the depth of occurrence.

Unraveling seasonal surface air temperature trends in Ukraine (1990—2021)

2025-07-08T12:15:25+03:00

This study examines the spatial and temporal characteristics of surface air temperature (SAT) changes in Ukraine from 1990 to 2021. It focuses on the seasonal and regional variabilities, long-term trends, the harmonic characteristics of the annual temperature cycle, and their implications for regional climate change.

From meteorological observations at 93 weather stations (Ω93 dataset), the average annual SAT was 9.6±0.8 °C. Over the past three decades, the mean rate of temperature increase reached a significant +0.64± 0.01 °C per decade, substantially exceeding historical averages. This warming trend is further evidenced by annual temperature anomalies, which showed only three years (1993, 1996, and 1997) with negative anomalies (ranging from −0.32 to −0.55 °C), while the remaining years were anomalously warm, with peaks in 2007, 2015, 2019, and 2020 (reaching up to +2.79 °C).

Monthly SAT trends revealed statistically significant warming across nearly all months, ranging from +0.34°C to +1.19 °C per decade. The most intensive warming was observed in December (+1.19±0.14 °C per decade), particularly in northern and eastern Ukraine. Conversely, January exhibited minimal or even negative trends in many regions, except for Crimea and southern Ukraine, where moderate warming persisted.

The amplitude and phase of seasonal SAT variations are reliable indicators of continental climate characteristics. In 1990—2021, the mean amplitude of the seasonal temperature cycle was 12.3 ± 1.0 °C, with a decreasing trend of approximately 0.1 °C per decade. This decline is largely attributed to warming during the warm season. The mean phase of the seasonal cycle was estimated at 1.29 ± 0.06 months. A slight phase shift of −0.012 months per decade was also observed over the study period.

The study highlights increased temperature variability during winter and spring months, contributing to a more comprehensive understanding of contemporary climate shifts in Ukraine. These findings underscore the urgent need for adaptive strategies to mitigate the impacts of ongoing climate change.

Distribution of thermodynamic parameters in the Dnieper-Donetsk basin. Relationship with structure and oil and gas content.

2025-09-09T08:54:18+03:00

Calculations of geothermal parameters of the Dnieper-Donetsk basin have been carried out. In all fields in part of wells the geothermal gradient is stable and is 20—21 °C/km, and in some it changes. It is negative to the west of the Chernihiv segment, where there are no fields. In its eastern part and the and western part of the Lokhvytsia segment, both positive and negative changes have been observed. In the eastern part of the Lokhvytsia segment and in the near-border parts of the Izyum block, they are exclusively positive.

Heat flux within the depression varies from 36 to 56 mW/m2, but over most of the territory it is 39—46 mW/m2. The most common values are 40—42 mW/m2. At the border of the Chernihiv and Lokhvytsia segments, in the southern near-border part and between the Lokhvytsia and Verkhovtsiv-Lgov fault zones (FZ), HF is increased to 45—48 mW/m2. The central part of the Izyum segment is characterized by low HF values (38—40 mW/m2). A major increase happens to the east of Western Azov Region towards Donbas.

The spatial distribution of heat flux and temperatures at a depth of 3000 m correlates with the location of the foundation FZ. To the west of the Lokhvytsia FZ, HF changes in areas where the north-eastern stretch zone intersects with the meridional zones. In the triangle between the Lokhvytsia to Verkhovtsiv-Lgov FZs, the influence of the latitudinal FZs (Kyiv—Hadyach and Andrushivka) is also evident. In the central part of the Izyum segment, the distribution of HF corresponds with the location of the latitudinal Starobilsk-Zhmerynka and longitudinal Axial FZs.

It is suggested that the increase in the gradient is a parameter of the thermal field that reflects modern tectonic and geological events: the recovery of permeable zones in the sedimentary strata which are related to the faults in the foundation and sedimentary layers, and temperature increase because of the injection of thermal hydrocarbonate-sodium deep waters. The depth of the gradient change is close to the depth of the strata containing hydrocarbon deposits.

In the Lokhvytsia segment, gradient changes in the Lower Carboniferous layers, which contain hydrocarbon deposits. In Izyum, the wells do not reach the Lower Carboniferous sediments, and the hydrodynamic regime is caused by the spread of impermeable salt diapirs.

Lithofacies analysis of the Productive Series deposits in the Bulla-Deniz oil and gas condensate field (Azerbaijan)

2025-05-06T12:08:27+03:00

The study of the Bulla-Deniz Field by geological and geophysical methods began in the 1950-sand continues up today. Since the oil-and-gas bearing objects of the field have a complex geological setting at considerable depth, their penetration, sampling and development are one of the most important problems of today. Therefore, a detailed study of the geological structure of the field is very relevant.

The object of our investigation is the Bulla-Deniz Field, located in the north-western part of the Baku Archipelago. Exploration works revealed here oil-and-gas condensate bearing successions of V, VII and VIII horizons of the Productive Series. The objective of the study was to refine the geological structure and depositional conditions of these Productive Series horizons as well as to assess their reservoir properties based on well log data.

Sequence stratigraphy is an important method in geological and geophysical research. This method can be used to improve significantly the prediction of the studied fields, as well as to reveal unconventional reservoir types. The facies analysis, one of the stages of sequence stratigraphic analysis, is applied for studying the facies predictions from log data. Since the beginning of the oil production era, the main objects of hydrocarbon exploration have been medium and large anticlinal traps. These have been actively developed; as a result, their potential as primary exploration targets is being gradually exhausted. Therefore, the main exploration objects are non-anticlinal traps, low-amplitude uplifts, and stratigraphic wedges. The modern integrated approach allows tracing the conditions of the formation of sedimentary basins and improving the very understanding of sedimentation conditions.

We applied to the sequence stratigraphic analysis, the Emery method, and the cyclostratigraphic analysis to the study area. Sedimentation conditions were established and analysed, and lithofacies analysis was carried out. Hydrocarbon-rich reservoirs were found to be predominantly in the low sea-level tract and, slightly less frequently, in the transgressive system tract. In most cases, deposits formed during the aggradation and retrogradation periods have good reservoir properties.

Spatiotemporal analysis of surface temperature dynamics in the Supii River basin using regression methods

2025-07-08T12:24:59+03:00

The research presents an approach for detecting spatial and temporal changes, specifically the annual increase in land surface temperature. The study area encompasses the Supii River basin, which spans the Chernihiv, Kyiv, and Cherkasy oblasts and flows into the Dnipro. This region is characterized by intensive agriculture, poor aquifer recharge, low-quality groundwater, and prolonged droughts.

Temperature data for July and August were obtained from publicly available Landsat mission archives for the period 1984—2024. It is recommended to recalculate Landsat thermal images based on emissivity, since their Level 2 product may contain pixels with missing information. To ensure the highest accuracy, pixels affected by clouds and their shadows were masked; the next stepinvolved time series analysis of the filtered images.

The time series analysis aimed to identify key patterns in the evolution of temperature dynamics, functionally dependent on various influencing factors. Accurate spatial alignment of the imagery enabled consistent undistorted calculation of the ground’s physical characteristics over the entire study area and for each year of observation. A simple linear regression was applied to each pixel in each raster image. To visualize the spatial distribution of long-term temperature dynamics, the regression gradient (or slope coefficient) was used, representing the average annual increase in temperature.

The results are presented as spatial indices of annual surface temperature growth within the Supii River basin, highlighting settlements with dominant positive trends, and the distribution by land use cover. This provides insight into where and to what extent climate conditions may become critical in the coming years, assuming the temperature continues to rise. As a mitigation measure, it is proposed to vegetate the urban and rural areas (particularly in larger local communities) to help reduce the impact of global warming.

The seismicity of the Carpathians in 2024

2025-09-02T11:37:22+03:00

According to the observations at the seismic stations of the Carpathian region of Ukraine in 2024, the main parameters of 55 earthquakes in the range of energy classes KR=5.5÷12.4 were obtained. The parameters of seismometric equipment at active seismic stations are given. A catalog of earthquakes, their distribution by regions and energy classes, a map of epicenters, graphs of seismic energy release, and the number of earthquakes in the region by month are presented. A brief description of the seismicity of certain seismically active areas of the Carpathian region is given. The total energy allocated to the region was ΣЕ=4.09·1012 J, which is an order of magnitude lower than last year’s ΣЕ=9.06·1013 J. This year, increased seismic activity was observed in three seismically active areas. Thus, 16 earthquakes of energy class KR=5.5÷9.8 were recorded in the North-Western region. Their total seismic energy was ΣЕ=1.53·1010 J. In this area, the strongest earthquake occurred on February 22 at 12h54m on the territory of Slovakia, near the town of Humenné, with KR=9.8 at a depth of h=12.9 km and epicenter intensity of I0=3 points. In the Vrancea region, as in the previous year, 19 events with magnitudes of 8.4—12.4 were registered, with the total seismic energy of ΣE=2.97·1012 J, which is higher than last year’s ΣE=6.41·1011 J. This year, there has been an increase in seismic activity in Bukovina compared to 2023. 10 earthquakes of an energy class of KR=5.7÷8.9 and a total seismic energy of ΣE=1.72·109 J were registered here. The earthquake foci were located in the crust at depths of h=1.0÷15.0 km. In the Southern Carpathians, there was a decrease in activity compared to 2023. In total, 2 earthquakes with KR=8.7 and 10.3 were registered here at depths of 5 and 7.7 km with a total seismic energy of ΣE=2.05·1010 J. A decrease in activity is also observed in the Crișan region. Only one event with KR=9.2 was registered here. This year, the Banat region has become more active. During the year, 3 earthquakes of KR=9.4÷12.0 were registered here, with the total seismic energy of ΣE=1.02·1012 J. In the Bacău region in 2024, only two earthquakes with KR=9.5 and 10.4 were registered, and none were registered in the Transylvania region. Two more earthquakes were registered in the region, but outside the seismic areas. The regional Carpathian hodograph was used to determine the main parameters of earthquakes in Transcarpathia, and the Jeffreys-Bullen hodograph was used for earthquakes in the Vrancea zone and other six districts.

Application of the thermoluminescence method and remotesensing techniques for studying quaternary sediments

2025-07-18T14:52:41+03:00

Quaternary sediments can be investigated by different physical, geophysical, and geochemical methods and modern remote-sensing techniques. The interpretation of remote-sensing imagery plays an efficient role in the study of geological objects and various geological processes. It is conditioned by the various technogenic factors and ea the composition and sequence of deposits of the area. The additional information from satellite images makes it possible to identify types of sediments. Combining satellite data with geological, geophysical, and geochemical approaches allows to analyze various types of anthropogenic deposits and to determine their main characteristics. It is proposed to apply remote sensing methods and the thermoluminescence method to anthropogenic sediments and determine their age. Thermoluminescence is applied to solve various geochronological tasks and to dateq Quaternary deposits. The main concepts of the thermoluminescence method have been considered. Our proposed approach for the dating of anthropogenic deposits is based on the Smakula-Dexter formula. The Smakula-Dexter formula calculates the concentration of radiation centers. A relation has been established between the age of the sample and the concentration of radiation centers. By solving a differential equation, a mathematical formula has been derived for the radiation coefficient, which is a component of the Smakula-Dexter formula. The higher the concentration of radiation centern, the older the sample is. Remote sensing methods and thermoluminescence can be combined to determine the age of rocks.

Assessment of energy potential in the Khizi tectonic zone of the Caspian-Guba research region (on the example of the Bayimdagh-Tekchay field)

2025-05-22T14:23:42+03:00

This study assesses the energy potential of the Khizi tectonic zone within the Caspian-Guba research region, focusing on the Bayimdagh-Tekchay field. Given Azerbaijan’s increasing emphasis on alternative energy sources, geothermal energy emerges as a viable and sustainable option. The region’s geothermal resources, mainly concentrated in the Greater and Lesser Caucasus, the Talysh-Lankaran zone, and the Kur-Araz basin, remain underutilized due to Azerbaijan’s rich oil reserves.

Thermal waters in the Caspian-Guba region have been analyzed based on stratigraphic data, geothermal measurements, and hydrogeological studies. The Siyazan monocline, a key tectonic feature, separates various geological formations and influences temperature variations with depth. Temperature distribution analyses in the Bayimdagh-Tekchay zone reveal a correlation between rock age, dip angles, and geothermal gradients. The Productive layerformation, predominantly consisting of conglomerates, gravels, and clays, plays a crucial role in subsurface heat retention.

Experimental findings indicate that the region possesses significant thermal water reserves, exceeding 30,000 m2/day in certain areas such as Khachmaz, Khudat, and Nabran. The study also highlights the potential for repurposing abandoned oil wells for geothermal energy production. Injected water, upon heating through rock contact, can be extracted to supply local heating networks, industrial facilities, and even power generation using the Organic Rankine Cycle or Kalina Cycle technologies.

An economic feasibility analysis demonstrates that energy extracted from selected wells in Bayimdagh-Tekchay could meet the heating requirements of hundreds of households. This underscores the importance of further investment in geothermal infrastructure to optimize energy recovery and enhance sustainability. The research ultimately advocates for a transition towards green energy in Azerbaijan, emphasizing geothermal energy’s role in reducing reliance on conventional fossil fuels while promoting environmental conservation.