Northern Sector Research Articles

Branch fault discovered in Tangshan fault zone on the Kaiping-Guye boundary, North China

Abstract One outcrop of the NE–SW-trending fault with a steep occurrence and grown gouge was discovered in the north segment of the Tangshan fault zone during a field survey near Jujialing village on the Kaiping-Guye boundary of Hebei province, North China. This zone has received less attention in seismic geologic surveys. In addition, three neighboring and parallel NE trending scarps with heights in the range of 1–1.5 m were discovered on the generally flat terrain close to the fault outcrop. The geochemical and multi-electrode resistivity surveys revealed sudden huge fluctuations in the Hg concentration within short distances from the fault outcrop and the three surface scarps. The multi-electrode resistivity survey also revealed a resistivity structure with extreme horizontal discontinuity, indicating the presence of a subsurface fault zone with a width of 40–50 m and a SE dip. This finding confirmed that the three surface NE trending scarps were late Quaternary fault scarps. Following an examination of the focal mechanism solutions and survey findings, it is suggested that the newly detected fault trending toward the northeast could be an unexplored branch fault in the flower structure of the northern section of the Tangshan fault zone. It is marked by recent activity that is mainly controlled by the right-lateral strike-slip. The discovery of this active fault is critical for an accurate assessment of the seismic hazard of north segment of the Tangshan fault zone.

Влияние космической погоды на надежность функционирования транспортных систем на высоких широтах

The review offered for the first time in the Russian scientific literature is devoted to various aspects of the problem of the impact of space weather on ground transport systems. An analysis of available information indicates that space weather disturbances can affect rail infrastructure through both direct and indirect effects on system components. One of the main hazards is geomagnetically induced currents (GICs) in grounded extended structures excited by the geomagnetic field disturbances. The telluric electric fields and currents associated with them can cause power outages and malfunctions in the railway automation track circuits. Indirect impact is possible through disturbances in the stable supply of electricity, disturbances in communication systems and in the appearance of positioning errors in global navigation satellite systems. The review provides information necessary for engineers of transport and energy systems about the main factors of space weather that could pose a threat to such systems. Examples of the influence of geomagnetic disturbances on the automatic signaling of the northern sections of Russian Railways are given. The prospects for monitoring space weather and the aurora oval for the needs of Russian Railways are discussed.

Understanding the magma-crust interaction: the role of the northern Gondwana margin in the genesis and evolution of the Jurassic Alvand plutonic complex (Sanandaj-Sirjan Zone, NW Iran)

This work investigates the petrogenesis of the main magmatic rocks of the Jurassic Alvand plutonic complex, located in the northern sector of the Sanandaj-Sirjan Zone of Iran. The Alvand complex is made up of a wide range of rocks spanning gabbro to leucogranites, containing a diversified range of enclaves, from mafic-to felsic- and surmicaceous-type. Here we present new textural characterization together with mineral, whole rock and Sr–Nd isotope chemistry of the main magmatic lithotypes. We integrated this new data with the available ones to understand the petrogenesis of the Alvand magmas and their interaction with the Ediacaran-Cambrian crystalline basement. A legacy of the Peri-Gondwanan crust is evident in Alvand felsic rocks. The whole rock chemistry, the Sr–Nd isotope ratios and assimilation-fractional crystallization numerical models indicate their genesis partly through differentiation via fractional crystallization from the coeval Alvand gabbros coupled with a concurrent and significative mass-addition of material from the Cadomian basement. At a wider scale, this work also provides new insights into the understanding the role of the continental crust in the buildup of transcrustal magmatic systems and therefore to a better comprehension of crust growth process driven by intense magma-crust interaction events.

Geochemistry of thermal springs and associated gases along the Strymon River Valley (Bulgaria and Greece)

This paper presents and discusses the water and gas geochemistry of a large number of thermal springs occurring along the N-S trending Strymon Valley, from its source, near Sofia (Bulgaria), to the Aegean Sea (Greece). In Bulgaria springs have markedly alkaline pH, relatively low Total Dissolved Solids and prevalent Na-HCO3 to Na-Cl(SO4) in composition while the associated gas phase is mostly N2-dominated. When moving to the Greek sector, the thermal springs, Ca(Mg)-HCO3 to Na-HCO3, become less alkaline and more saline whereas the associated gas phase is CO2-dominated. The abrupt geochemical change in the Greek sector is caused by a variation in the thickness and nature of the sediments filling the Strymon Valley, the latter being characterized by a relevant amount of Neogene marine material. Such changes occur south of an important E-W lineament named Middle Mesta, south of which marble formations extensively crop out and are likely occurring below the sedimentary succession. The presence of these carbonate sequences embedded in the Neogene sediments is explaining the CO2-rich gases associated to the Greek springs. Water isotopes indicate a meteoric origin for the studied waters. From a geothermometric point of view, solute (previous studies) and gas (this work) geothermometers suggest that no high enthalpy systems occur in the Bulgaria and northern sector of Greece with estimated temperatures <120 °C. Consequently, these thermal springs can be regarded as tectonically-derived along the many fault systems that border the Strymon Valley. The convective circuits are thus originated from rainfall in the crystalline massifs that border the valley, i.e. the Serbo-Macedonian to the west and the Rhodope to the east.

A High Spatiotemporal Enhancement Method of Forest Vegetation Leaf Area Index Based on Landsat8 OLI and GF-1 WFV Data

The leaf area index (LAI) is a crucial parameter for analyzing terrestrial ecosystem carbon cycles and global climate change. Obtaining high spatiotemporal resolution forest stand vegetation LAI products over large areas is essential for an accurate understanding of forest ecosystems. This study takes the northwestern part of the Inner Mongolia Autonomous Region (the northern section of the Greater Khingan Mountains) in northern China as the research area. It also generates the LAI time series product of the 8-day and 30 m forest stand vegetation growth period from 2013 to 2017 (from the 121st to the 305th day of each year). The Simulated Annealing-Back Propagation Neural Network (SA-BPNN) model was used to estimate LAI from Landsat8 OLI, and the multi-period GaoFen-1 WideField-View satellite images (GF-1 WFV) and the spatiotemporal adaptive reflectance fusion mode (STARFM) was used to predict high spatiotemporal resolution LAI by combining inversion LAI and Global LAnd Surface Satellite-derived vegetation LAI (GLASS LAI) products. The results showed the following: (1) The SA-BPNN estimation model has relatively high accuracy, with R2 = 0.75 and RMSE = 0.38 for the 2013 LAI estimation model, and R2 = 0.74 and RMSE = 0.17 for the 2016 LAI estimation model. (2) The fused 30 m LAI product has a good correlation with the LAI verification of the measured sample site (R2 = 0.8775) and a high similarity with the GLASS LAI product. (3) The fused 30 m LAI product has a high similarity with the GLASS LAI product, and compared with the GLASS LAI interannual trend line, it accords with the growth trend of plants in the seasons. This study provides a theoretical and technical reference for forest stand vegetation growth period LAI spatiotemporal fusion research based on high-score data, and has an important role in exploring vegetation primary productivity and carbon cycle changes in the future.

Mapping alteration zones in the Southern section of Yulong copper belt, Tibet using multi-source remote sensing data

Methods for extracting mineralized alteration information using remote sensing images have recently become both efficient and cost-effective. Technology involving the extraction of alteration information based on multi-spectral data has been widely practiced and effectively verified. In recent years, research on fine mineral extraction methods based on hyperspectral data has also been rapidly developing. The Yulong copper belt is a porphyry copper belt located in China with high prospects for mineralization. However, most previous studies focused on the northern section of the Yulong copper belt, with limited exploration of the southern section. In this study, alteration information of the southern section of the Yulong copper belt was extracted from remote sensing data from Landsat-8 OLI, ASTER, and ZY1-02D, and the prospecting potential of this area was evaluated. Principal component analysis was used to extract iron oxide and hydroxyl alteration from Landsat-8 data, in addition to Al hydroxyl and propylitic alterations from ASTER data. Considering the challenge of the extraction of too many pseudo-anomalies using traditional methods, the mixture-tuned matched filtering (MTMF) method was used to more accurately extract iron oxide alterations. Regarding hyperspectral data, the minimum noise fraction and pure pixel index algorithms were used to extract white mica and carbonatite endmembers. The MTMF method was also used for alteration mapping, which took advantage of sub-pixel abundance mapping to finely divide the white mica and carbonatite alterations into five classes. The extraction results of multi-source remote sensing data were then compared and analyzed to avoid occasional single-image extraction results, which confirmed the superiority of the hyperspectral remote sensing and MTMF methods. Combined with field verification, the mineralization alteration information coincided with the spatial location of the Secuo, Mamupu, and Jicuo deposits, which confirmed the accuracy of alteration information extraction. The results of this study confirmed the application potential of remote sensing alteration information extraction in the field of mineral resource exploration. The results have important reference significance for further geological prospecting and exploration in the southern section of the Yulong copper belt.

Corporate tax fraud and public current income in the northern commercial sector of Guayaquil. A qualitative approach

Tax fraud is a very large problem within the economies of Latin America and Ecuador, it is no exception; the northern commercial sector of the city of Guayaquil was located as the object of study, which presents a problem with a limited current income due to tax fraud, raising as main objective: to characterize the relationship between corporate tax fraud and public current income in the period 2018-2020. The research design is qualitative. The interview technique was used and applied to ten experts chosen for convenience. The results show that tax evasion is an evasion mechanism that directly affects current revenue and affects the funds available to the State to improve strategic sectors for the benefit of society in general. It is concluded that the general objective was met, recommending that there should be greater tax control by the competent national body and studies should be conducted to help estimate efficient calculation mechanisms for tax evasion and money laundering that affect the economy of Guayaquil.

Estimations of Secchi depth from the turbid Eastern China Coastal Seas using MODIS data

ABSTRACT In this study, a neural network-based Secchi depth retrieval model (NNSD) was developed using observations obtained during 2003–2012 in the Bohai, Yellow, and China East Seas (Eastern China Coastal Seas, ECCS). Based on the results of the analyses, the NNSD model produced less than 25% uncertainty in quantifying the Secchi depth in the optically complex ECCS. The slope of the linear relationship between the field-measured and NNSD model-derived Secchi depth varied from 0.98 to 1.08 among the datasets. However, the corresponding determination coefficients were not any lower than 0.91. To determine the effectiveness of the NNSD model in deriving the Secchi depth in the ECCS, the performances of the three existing models were also evaluated, and the results are presented in this study. By comparison, using the NNSD model decreased the uncertainty by 26% when compared with the three existing models in deriving the Secchi depth in the ECCS. Finally, the NNSD model was further applied to the MODIS data over the ECCS to briefly illustrate its applicability to general oceanographic studies. The NNSD model could produce 24.62% MRE and 0.14 RMSE values in deriving the Secchi depth from the ECCS, which was > 26% MRE and > 0.07 RMSE values better than all the BGSD, KDSD and SASD models. In regards to the spatial distribution pattern of the Secchi depth, the eastern and northern sections of the ECCS were much higher than the western and southern areas. Additionally, the temporal distribution mode indicated that the winter season was higher than the summer season. These spatiotemporal characteristics were caused primarily by the regional climate, river discharges, and strong tidal currents and winds, among other factors.

A geophysical multidisciplinary approach to investigate the shallow subsoil structures in volcanic environment: The case of Ischia Island

The ability to image the underground structures of volcanoes is limited by the precision, resolution and penetration depth of each single geophysical method. In order to improve the knowledge of specific volcanic edifices and to better understand the general behavior of structures, the use of a combination of methods is strongly recommended to exploit and maximize their complementary capabilities of resolution and penetration depths.In this work a large dataset of seismic and electromagnetic measurements has been used to provide a more detailed and improved geophysical image of the shallower portion of the northern sector of Ischia Island (Campania region, Italy), severely hit by the August 21, 2017 earthquake (Mw 3.9). We analysed data by using different methodologies: Horizontal-to-Vertical Spectral Ratio (HVSR), seismic array technique (f-k), polarization analysis and Time Domain ElectroMagnetic (TDEM) survey. These methods are sensitive in a different way to tectonic features, lithologies, layer geometry and fluid distribution. Thus, their combination is useful for studying sites with complex crustal structures such as Ischia island, which is characterized by a well-developed geothermal system linked to the presence of a shallow magmatic body. Results of our study provides detailed information of the physical properties of the subsoil through: 1) the spatial distribution of the amplification parameters of ground motion, showing frequency peaks below 1 Hz and/or between 1 Hz and 5 Hz; 2) the definition of the velocity models up to 600 m depth, with shear wave velocities ranging from 150 m/s for the shallower layers to 2500 m/s for the half space; 3) the recognition of the correlation between the principal fault structures and polarization directions of the noise wavefield, mostly oriented along EW and NE-SW directions; 4) the resistivity models of the first 80 m depth with high resistivity values of the shallow layers in the range 50–100 Ω.m and low resistivity values of the bottom layers in the range 1–10 Ω.m.

Holocene deglaciation of the northern Fildes Peninsula, King George Island, Antarctica

AbstractThe timing and magnitude of Holocene glacial oscillations in most currently ice‐free areas of Antarctica remain unknown. This work focuses on the recent deglaciation in the northern sector of the Fildes Peninsula, King George Island, northern Antarctic Peninsula. The ice cap covering ca. 90% of the island has receded since the Last Glacial Maximum and exposed ca. 29 km2 of ice‐free land. We reconstruct its glacial history based on a dataset of 12 36Cl exposure ages obtained through cosmic‐ray exposure (CRE) dating of moraine boulders, polished surfaces and erratic boulders surrounding the peninsula's northern plateau. Results reveal that the deglaciation of the northern Fildes Peninsula took place during the Holocene Thermal Maximum at 7–6 ka, when warm conditions promoted a massive glacial retreat. The present arrangement of ice‐free areas was in place by 6 ka. Small cirque moraines suggest the subsequent occurrence of favourable climate conditions for glacial expansion fed by intense snow deflation at 4.6 and 1 ka at the foot of the northern plateau. The deglaciation pattern of the Fildes Peninsula resulted from the combined shrinkage of different ice masses, rather than of the long‐term retreat of the King George Ice Cap. No evidence of glacier expansion during more recent cold periods (i.e. the Little Ice Age) was found. These results fit well with regional deglacial histories inferred from lacustrine sediments and raised beaches and complement the existing chronological framework to help better understand the peninsula's Holocene geoecological dynamics.

Impact of the extremely warm Gulf Stream on heavy precipitation induced by Hurricane Sandy (2012) during its extratropical transition

This study investigated the role of the extremely warm sea surface temperature (EWSST) over the Gulf Stream (GS) in heavy precipitation induced by Hurricane Sandy in October 2012 during its extratropical transition (ET). A control (CTL) run with observed SST and a climate (CLM) run with climatological SST over the GS were performed using a high-resolution regional atmospheric model. Sandy-induced precipitation over the Mid-Atlantic coastal region was larger by approximately 40% in the CTL run than in the CLM run during its ET phase. The western sector of Sandy in the CTL run exhibited the westward-tilting lower-to-middle tropospheric front and the pronounced convectively unstable layer created by large surface fluxes of sensible and latent heat from the EWSST region. The intensified convective instability was released by the frontal deep updrafts, enhancing frontal precipitation in the western part of Sandy. A backward trajectory analysis demonstrated that the abundant moisture evaporated from the GS was imported into the western frontal rainbands by the low-level easterlies passing the northern sector of Sandy. The EWSST facilitated the moistening process of air parcels transported by the easterlies due to the active heat and moisture supply from the underlying current, contributing to the increase in moisture influx toward the western front. Another trajectory analysis indicated that the formation of low-level easterlies north of Sandy originated from the combination of Sandy and high-latitude synoptic-scale systems such as an anomalous high over the Labrador Sea and an extratropical cyclone east of Sandy. These results corroborate the importance of the extremely warm midlatitude ocean and complex high-latitude weather systems to the enhancement of Sandy-induced heavy precipitation.

Coupled coastal monitoring framework for the analysis of beach stability and nearshore hydrodynamics of a structure influenced medium energy coast in India

This study presents a Coupled Coastal Monitoring Framework (CCMF) that integrates remote sensing (CoastSat), video beach monitoring system (VBMS), and numerical modelling to analyse the morphology and hydrodynamics of a structure-influenced beach. A 10.2 km stretch of straight beach with an artificial breakwater along the Kozhikode coast of Kerala, India, is selected for the study. The shoreline change analysis revealed that 38% of the total coast is under erosion, with the northern sector of the breakwater being highly erosive and the southern sector being stable. Continuous monitoring from the VBMS confirmed the stability of the southern sector with varying erosion accretion trends during 2018–21. Coastal morphological features such as double bars, cusps, and rip-like formations were identified through the VBMS, validated and analysed in detail with distinct wave-current interactions and sediment transport through numerical modelling. The study concludes that the breakwater is effectively protecting the beach adjacent to the south but has disturbed longshore transport, potentially leading to increased erosion to the north. The proposed CCMF provides real-time and post-performance monitoring of structure-influenced beaches, enabling timely decision-making at critical locations and appropriate remedial measures for efficient coastal management.

Provenance and deposition of a lithified volcanic-rich layer (VRL-5.5) at 5.5 Ma from Central Apennines (Italy)

Two slightly lithified volcanic rich layers (VRL) (former tephra) SVT-2 (San Vittorino) and CAC (Castiglione a Casauria) were sampled from two distinct post-evaporitic Messinian stratigraphic sections (Abruzzo, Central Italy). They crop only few tens of km apart and are predominantly massive, although some specimens show sedimentary structures. Both VRLs were investigated for the first time by field, mesoscopic, X-ray powder diffraction (XRPD), transmission optical microscopy (TOM), scanning electron microscopy (SEM), bulk composition, electron-microprobe analysis (EMPA) and quantitative textural attributes by image analysis. The XRPD analysis detects the presence of a glass phase, plus few (< 2 area %) magmatic-like feldspars, clinopyroxene and biotite and stratigraphically variable sedimentary minerals such as calcite, dolomite, illite and montmorillonite (from 0 to 40 area %). The 2D image analysis performed on SEM microphotographs reveals that both sections are composed of very fine glass shards, magmatic minerals are never isolated, whilst the carbonate crystals mainly fill voids among volcanic particles. Both these VRLs have identical rhyolitic glass compositions that closely overlap with those of previously-studied coeval and stratigraphically related sections occurring in the northern Apennine region and dated as 5.5 Ma. The 2D textural features of glassy particles (length, width, aspect ratio, grain-size distribution, MZ , σi, SKi, KG and roundness) in both SVT-2 and CAC sections are very similar and also close to the northern section of Camporotondo (Marche region). The outcomes provided here indicate that SVT-2 and CAC sections represent the southernmost distal deposits of the same large eruption that occurred about 5.5 Ma (VRL-5.5). They result from distal fallout of tephra through seawater, occasionally remobilised under low energy and localised conditions, especially in the uppermost part of the CAC section. All the VRL-5.5 rocks are probably related to a very large eruption that occurred in the Carpathian-Pannonian magmatic district. The analytical protocols used in this study can be useful to investigate other ancient volcanic-rich layers, corresponding to lithified tephra.

Assessment of Human Health Risk of Metal(Loid) Content in Brazilian Sardine Along the Southwestern Atlantic.

The Brazilian sardine (Sardinella aurita) is an important food resource found in the subtropical Southwestern Atlantic Continental Shelf (CSSWA), but limited information about its metal(loid) concentrations is available, restricting effective risk assessment by its consumption. On this research, we hypothesized that S. aurita presents different metal(loid) concentrations within a latitudinal gradient in the CSSWA (northern and southern sectors). We also assessed the S. aurita consumption contamination risk in both sectors of the CSSWA. The results indicated that S. aurita might present different chemical and contamination profiles between the observed sectors, with highlights to As, Cr, and Fe at greater levels than the safety limits established by regulatory agencies. Such finds could be explained by urbanization, industrialization, continental and oceanographic processes along the CSSWA, corroborating our hypothesis for most observed metals(loid). On the other hand, our risk assessment analysis of metal(loid) concentrations did not indicate hazards for human consumption.

Assessment of beach morphological changes in the east coast of India during cyclone Phethai, through field data and numerical modeling

Episodic extreme waves caused by cyclones can have catastrophic consequences for coastal zones, including drastic beach morphology changes. The present study analyzed the beach morphological changes from Kakinada to Konapapapeta on the southeast coast of India before, during, and after the tropical cyclone Phethai using field survey and numerical modeling. Beach profiles were collected using Trimble RTK GPS and shoreline tracking was performed with handheld GPS. Numerical modeling was carried out using MIKE software to estimate the sediment transport rate before, during, and after the cyclone. Although the intensity of the cyclone reduced to a deep depression before landfall, several morphological changes were observed. Erosion was higher in the northern sector, where the beach width was less, and prominent scarps were seen throughout this region after the cyclone. The inundation varied from 40 to 120 m during the cyclone due to a storm surge of 0.5 to 1 m. During the cyclone, significant wave heights reached up to 4 m. The gross sediment transport rate is 3 to 13 times greater during the cyclone period than during the non-cyclone period. The maximum gross sediment transport rate during the Phethai cyclone was 1040 m3/day. Sediment transport was estimated for the same site for the non-cyclone year 2019, and the gross transport rate was 26,174 m3. As it is projected that extreme events are likely to increase due to climate change, output from this type of study is vital to environmental managers to assess erosion and develop long-term mitigation plans.

Hydrogeochemical Study of Hot Springs along the Tingri—Nyima Rift: Relationship between Fluids and Earthquakes

Studying the hydrogeochemical characteristics of hot springs provides essential geochemical information for monitoring earthquake precursors and understanding the relationship between fluids, fractures, and earthquakes. This paper investigates the hydrogeochemical characteristics of hot springs along the Tingri–Nyima Rift (TNR) in southern Tibet, a seismically active zone at the collision front of the Indian and Asian-European plates. The major elements, hydrogen, and oxygen isotopes of seven thermal springs were analyzed from July 2019 to September 2021. The findings indicate that Mount Everest’s meteoric water, which has a recharge elevation of roughly 7.5–8.4 km, is the main source of recharge for the hot springs. The water samples have two main hydrochemical types: HCO3-Na and Cl-Na. The temperature of the geothermal reservoir is between 46.5 and 225.4 °C, while the circulation depth is between 1.2 and 5.0 km based on silica-enthalpy mixing models and traditional geothermometers. Furthermore, continuous measurements of major anions and cations at the Yundong Spring (T06) near Mount Everest reveal short-term (8 days) seismic precursor anomalies of hydrochemical compositions before an ML4.7 earthquake 64.36 km away from T06. Our study suggests that seismicity in the northern section of the TNR is controlled by both hydrothermal activity and tectonic activity, while seismicity in the southern section is mainly influenced by tectonic activity. In addition to magnitude and distance from the epicenter, geological forces from deep, large fissures also affect how hot springs react to seismic occurrences. A fluid circulation model is established in order to explain the process of groundwater circulation migration. The continuous hydrochemical monitoring of hot springs near Everest is critical for studying the coupling between hot springs, fractures, and earthquakes, as well as monitoring information on earthquake precursory anomalies near Everest.

Three-dimensional density distribution and earthquake activity of the northern Lancangjiang fault in eastern Tibet

Due to the collision and lateral compression of the Indian-Asian plate, the Lancangjiang fault has become one of the most active strike-slip faults in the Qiangtang plate. The Qamdo 2013 Ms6.1 earthquake was induced from the northern section of the fault (the northern Lancangjiang fault). The destruction of the earthquake seriously endangers human activities and the construction of the Sichuan-Tibet Railway. However, there are few high-resolution geophysical data in this area, which limits the understanding of the deep structure, motion mode and seismic activity of the northern Lancangjiang active fault. In this paper, new gravity data were observed at a scale of 1: 200,000, covering an area of 1500km2. Based on wavelet multiscale decomposition, scratch analysis and 3-D inversion of gravity data methods, we obtained gravity anomalies of different scales, faults distribution and density structure. The results show that the overall crustal density change in Qamdo area is obvious and closely related to the distribution of faults. The Qamdo earthquake occurred at the layered interface with steep density change and the result from scratch analysis shows that the stress is concentrated at this position. We believe that the existence of stratigraphic density difference leads to different ability of strata to withstand regional tectonic stress, which is an important cause of the Qamdo earthquake. We analyzed the differences magnitude of earthquake activity between the northern Lancangjiang fault and Kamaduo-Gangtuo fault and believe that the northern Lancangjiang fault is more conducive to the preparation of large earthquakes. Otherwise, this paper provides geophysical evidence for the hypothesis that the northern Lancangjiang fault thrusts to the Qamdo Basin at a high angle.

Application of simulation to optimize the oil-gathering system of the “N” oil field

Background: In the period of 20122021 456 wells were drilled in the western, northern and central sections of the N oil field. The construction of additional wells in the coastal zone (western part) will increase the volume of liquid entering the Group Metering Plant (GMP) -A, which is already operating above designed capacity. Given the above, it was decided to build a new GMP-P on the western section.&#x0D; Aim: The purpose of this work was the need to determine the optimal option for placing the designed GMP-P.&#x0D; Materials and methods: A hydraulic calculation of the Oil Production Shops oil gathering system (OPS) of the N field was carried out by simulating a multi-phase steady flow in a specialized software package with conversion using a geographic information system for reference to the terrain.&#x0D; Results: For the first time, the OPS-1 oil gathering pipeline system of the N field was completely digitized. In the course of the work, 4 options for optimizing the OPS-1 gathering system with different locations for the construction of the GMP-P were considered.&#x0D; Conclusion: Based on the results of the study, option 2 of the GMP-P construction location was selected and justified.

Modelling of the Fate of 137Cs and 90Sr in the Chornobyl Nuclear Power Plant Cooling Pond before and after the Water Level Drawdown

During the accident in April 1986, the Cooling Pond (CP) of the Chornobyl Nuclear Power Plant (ChNPP) was heavily contaminated by fuel particles and radionuclides of cesium-137 (137Cs) and strontium-90 (90Sr). Starting from the end of 2014, a gradual decrease of the CP water level began leading to the transformation of the whole reservoir into eight separate sectors and raising the concern of the fate of 137Cs and 90Sr in the future. In this study, two mathematical models were applied to reproduce radioactive contamination of the CP from 1986 to 2021 and to provide a forecast of 137Cs and 90Sr concentrations in the CP water from 2022 to 2030. The hydrodynamic model THREETOX provided three-dimensional (3D) currents in the CP corresponding to hydrological conditions before and after water level drawdown, and these currents were used in the box model POSEIDON-F for the long-term simulations of the changes in 137Cs and 90Sr concentrations in water, bottom sediments, and biota. Seasonal changes in the distribution coefficient (Kd) describing the partition of 137Cs between water and sediments were considered in the box model, which allowed us to reproduce the observed variations of concentration. Calculated concentrations of 137Cs and 90Sr in water and freshwater fish occupying different trophic levels agreed well with measurements for the entire post-accident period. After the water level drawdown, concentrations of 137Cs in the CP water slightly increased in all eight sectors, while 90Sr concentrations significantly increased in sectors close to ChNPP, which was explained by an additional 90Sr source when comparing the simulation results and measurement data. Using the model forecast from 2022 to 2030, we predict that the concentration of both radionuclides will gradually decrease in new water bodies of the Cooling Pond except in the northern sectors, where the suggested additional source of 90Sr will lead to a stabilization of 90Sr concentrations.

Patterns of the red-listed epiphytic species distribution in coniferous-deciduous forests of the Moscow Region

Epiphytes model the diversity of forest communities and indicate the integrity of natural ecosystems or the threat to their existence. The high sensitivity of epiphytic species to the environmental quality makes them good indicators in anthropogenic landscapes. The study deals with the distribution patterns of rare indicator epiphytic species at the border of their range in the broadleaved– coniferous forest zone, in the central part of the East European Plain within the Moscow region. The distribution and abundance of eight lichen species Anaptychia ciliaris, Bryoria fuscescens, B. implexa, Usnea dasopoga, U. glabrescens, U. hirta, U. subfloridana and the epiphytic moss Neckera pennata were studied. The main environmental factors at the regional level were climate variables based on the Worldclim database, water indices based on Sentinel-2 multispectral remote sensing data, and the anthropogenic impact factor in terms of the Nighttime lights of the earth’s surface based on the Suomi NPP satellite system. It was revealed that the vast majority of records were in the western and northern sectors of the region, i.e. in the broad-leaved–coniferous forest zone, while the vast majority of 0-records were in the southern and eastern sectors, in the area of broad-leaved and pine forests and extensive reclaimed wetlands. The association with different types of communities and biotopes, as well as tree species, was assessed at the ecosystem level, using field data. It has been established that the distribution of the studied species is governed by natural-geographic features of the territory. The principal limiting factors are air pollution, ecological restrictions (high humidity requirement of sites), cutting of mature forests and formation of local anthropogenic infrastructure. In perspective the study of ecology and living conditions of the studied rare species will help determine the optimal conditions contributing to biodiversity conservation in forests near large metropolitan areas and optimization of habitat diversity.