Southwestern Slope Research Articles

Simulation of a Potential Sector Collapse on the Koryaksky Volcano and Volcanic Hazard Assessment for the Yelizovo-Petropavlovsk Agglomeration (Kamchatka)

Based on the modeling of a potential sector collapse on the Koryaksky volcano, the most probable direction of movement of a debris avalanche is shown. Periodic fumarole activity of the volcano indicates the circulation of meteoric waters and favorable conditions for the replacement of the volcano bedrock with the development of landslide deposits. On the basis of satellite data, deformations of the earth's surface have been studied. The northeastern slopes of Koryaksky volcano rise relative to the descending southwestern slopes. Taking into account the fact that Avachinsky volcano, which is located 10 km from the Koryaksky volcano, has formed powerful landslide-explosive deposits in the history of its development, the relevance of this study is extremely high. Within the Yelizovo-Petropavlovsk agglomeration (which includes the cities of Yelizovo, Petropavlovsk-Kamchatsky and the adjacent settlements of the Yelizovsky district), which is located in the immediate vicinity of the Koryaksky volcano, more than half of the total population of the Kamchatka region lives and there are enterprises that bring more than half of all financial profit of the region. Therefore, the assessment of hazardous natural processes on the Koryaksky volcano in order to further develop a plan to minimize their negative consequences is critical for the economy of Kamchatka.

Results from the further development of CGI inversion on simulation and field data systems

AbstractA new series expansion-based method, the Combined Geoelectric Weighted Inversion (CGWI) procedure is presented and tested by using synthetic and in-field measured datasets. The method is an improved version of the Combined Geoelectric Inversion (CGI) robustified by involving Cauchy-Steiner weights in an Iteratively Reweighted Least Squares technique. The new procedure is compared to the Fourier series expansion-based 1.5D and the CGI methods as well as to the broadly applied RES2DINV inversion procedure. The field measurements are performed during stone exploration in an active quarry on the south-western slopes of the Mátra mountains, in northern Hungary. It is shown that the CGWI method gives stable and robust parameter estimation with acceptable accuracy. The comparison with other inversion methods is based on data distances, estimation errors and correlation parameters calculated on the base of the parameter correlation matrix.

Deep-seated gravity instability of the southern apron of the Ischia volcanic island (Tyrrhenian Sea, Italy)

Ischia Island is an active volcano representing the emerged sector of an E-W trending volcanic ridge largely extending undersea. Its collapsing behaviour, mainly in the form of fast-moving, terrestrial and submarine debris avalanches, has been recognized during the Holocene, but much less is known about previous gravity-driven processes. Using high-resolution multibeam bathymetric data and seismic reflection profiles, we provide evidence that the Island's southwestern flank has been involved in a slow-moving, deep-seated slope deformation that has displaced large volumes of its apron since the Late Pleistocene and until very recent or contemporary times. A long tongue of deformed seafloor, spreading up to 45 km from the Island over an area of 330 km2, between 500 and 1300 m water depths, has been detected along its southwestern slope. Different types of mass movements, genetically associated with each other, characterize this landslide: 1) a basal slump anticline, corresponding to a bulge on the bathymetry detaching at about 400 m sub-bottom depth; 2) an intermediate-mass movement chiefly consisting of debris avalanches and debris/turbiditic flows; 3) an upper mass movement consisting of hundred-metre size slumps detaching at relatively shallow depths. Conservative estimates indicate that at least 50 km3 of volcano-clastic and hemipelagic deposits have been mobilized, most of which comprise the basal slump anticline. This submarine landslide can be explained as a gravity failure of the continental slope unrelated to volcanism or rather as a process related to the dynamics of the volcanic edifice, which would imply volcano-spreading.

Oil-and-gas potential of the northeast Predpatom trough

This article discusses the geological structure and prospects of the oil and gas potential in the northeastern part of the Predpatom trough. The materials of the study included geological findings from deep drilling and data from direct geochemical studies conducted in recent years. It describes the specific features of the structural plans of the upper versus the lower part of the geological cross-section. It is assumed that deep drilling in the area of the Ulugur structure has not reached the target productive horizons in the autochthonous part of the section. After acquiring more recent seismic data, there is a proposal to drill a deeper exploratory well in the area. As another priority target for oil and gas exploration, a potential zone of Vendian clastic deposits wedging on the southwestern slope of the Suntar uplift has been identified. A forecast has been made for the distribution of lithological traps stacked with well-sorted granular Vendian reservoirs in the northern parts of the Ergedzheysky and Ulugursky license areas. In the allochthonous part of the section, the potential for oil and gas content in carbonate deposits from the Vendian and Lower Cambrian periods is highlighted in reservoirs formed by secondary processes. It is assumed that thrust deformations could lead to the circulation of aggressive solutions, resulting in the formation of secondary fractured cavernous reservoirs. Subsequently, hydrocarbon accumulations may migrate and accumulate within these reservoirs. Good gas prospects were also noted in the upper part of the section, where gas deposits were confirmed in newly discovered fields. The results of direct geochemical testing of the Ulugur and Ergedzheysky license areas are presented, enabling the preliminary delineation of promising zones and areas in the studied territory. At the same time, narrow elongated geochemical anomalies are associated with the prospects of the allochthonous part of the section, while isometric anomalies are linked to the autochthonous part of the section. The need to consolidate all available geological and geophysical information on the Pre-Atomic deflection within the framework of case studies is noted.

Estimation of groundwater recharge from groundwater level fluctuations and baseflow rates around Mount Meru, Tanzania

Estimating groundwater recharge, direct runoff and baseflow is essential for understanding groundwater resource availability and managing groundwater systems. This study estimates groundwater recharge, direct runoff and baseflow on two slopes of Mount Meru: the northern and southern slopes using the water-table fluctuation (WTF) method and baseflow separation technique. High-frequency groundwater level measurements in five shallow wells over three hydrological years from 2018 to 2021 were analysed, while streamflow data in four gauging stations over nine hydrological years from 2010 to 2019 were used. The results of the WTF method show that the aquifer undergoes an average recharge of 544 mm/year and 90 mm/year on the south-western and north-eastern slopes, respectively. On average, this recharge is about 53% and 13% of the annual rainfall on each slope. The baseflow results show that the aquifer on the south-eastern and north-western slopes recharges an average of 88 mm/year and 54 mm/year, respectively, which is on average about 12% and 7% of annual rainfall, respectively. In general, the high recharge on the south-western slope is attributed to the high rainfall, and the high hydraulic conductivity and high hydraulic diffusivity of the pyroclastic deposits compared to the debris avalanche deposits on the north-eastern slope. In addition, debris avalanche deposits show homogeneous recharge conditions, while pyroclastic deposits show heterogeneous recharge conditions. The WTF method can be useful to identify areas of preferential recharge so that preferential groundwater flow paths can be mapped for focused recharge of surface runoff during the rainy season.

The influence of slope exposure on the yield characteristics of winter wheat and spring barley in the Oka River basin, Russia

<p>We studied the relationship of the yield of winter wheat and spring barley with slope exposure components in the west of the Oka River basin. The size of the study area was 250 km by 360 km. The yield characteristics included the maximal yield obtained when applying the optimal dose of fertilizers, the yield without applying fertilizers (control) and the maximal addition to yield, that is, their difference. The addition is shown to be most sensitive to climatic factors. For wheat, the addition increased on the warmer south-western slopes, and for barley—on the wetter north-eastern slopes. The high sensitivity of the addition for barley to moisture is shown using it comparison with climatic water deficit. To compare slopes by the energy of incident solar radiation, we used the slope insolation in energy units. Although the difference in energy between the south-west and north-east slopes was only 2.2%, wheat addition on these slopes varied by more than a factor of two. The reasons for this are discussed. The results obtained show that when choosing locations for crop areas, it is advisable to take into account the exposure of the slopes.<strong></strong></p>

Roadside habitat connectivity for declining woodland birds in Australian farmland: A case study from the New South Wales South Western Slopes

The decline of birds in farmland is a conservation and land-management issue of global concern. Linear woodland corridors along roadsides in Australian farmland can play an important network role, maintaining ecological connectivity at the landscape scale and thereby supporting the survival of disturbance-sensitive woodland species. This paper presents a case study investigating the connectivity value of Old Narrandera Road, an old (pre-1870) roadside woodland corridor linking three larger woodland remnants near Wagga Wagga, in southern inland New South Wales, Australia. A survey of 120 plots along this corridor during 2018–2019 identified 81 bird species including 25 declining woodland birds of known conservation concern. Presence of the hyper-aggressive Noisy Miner Manorina melanocephala in survey plots was negatively correlated with total species richness and declining woodland bird assemblage richness and several species (predominantly small to medium-sized declining woodland birds rather than common farmland birds) exhibited a degree of spatial separation with Noisy Miners. One decliner, Grey-crowned Babbler Pomatostomus temporalis, showed a significant positive association with Noisy Miner, potentially reflecting a greater tolerance to harassment by Miners. Although the Noisy Miner is probably limiting realisation of the connectivity value of this woodland corridor at present, corridors as substantial and significant as Old Narrandera Road are scarce in the local landscape, and the woodland complex of three interconnected remnants it brings together is likely to be important for the local conservation of many declining woodland bird species.

Ultrahigh-Pressure Orange Garnets from the Sedimentary Deposits of the Upper Bug Area (Ukrainian Shield)

The article is dedicated to the investigation of orange garnets from Miocene-Pliocene deposits of the Balta suite and the Sarmatian stage in the Vinnytsia area. The Vinnytsia area is located on the southwestern slope of the Ukrainian Shield. The crystalline basement on most of the area is represented by granitoids of the Berdychiv complex of Paleoproterozoic age, and to a lesser extent by enderbites and charnockites of the Lityn complex of Neoarchean age. Among these, there are mafic and ultramafic bodies ranging from 0.5 to 2 meters in thickness. The sedimentary cover with a total thickness of up to 20 m is represented by sands and clays of the middle Sarmatian, Balta and Quaternary sediments. These deposits are enriched with mantle minerals, predominantly pyrope, and four diamond crystals have also been discovered. We studied the chemical composition (253 crystals) and morphology (278 crystals) of the orange garnets. The studied samples are mostly represented by garnets of pyrope and pyrope-almandine composition, a small part is represented by grossulars. Most of the garnets are unrounded crystal fragments ranging in size from 0.2 to 0.6 mm, exhibiting signs of intense hypergene changes. These are evident in the development of positive (block) and negative relief features, appearing as drop-shaped, cone-shaped, small hilly microrelief and various forms of etching channels. The morphological features suggest that these garnets were probably relocated a short distance from their primary sources and had been present in the weathering crust for an extended period. The original sources of garnets are most likely Precambrian and located on active tectonic zones, which led to their destruction. According to chemical composition data, among orange garnets low-chromium websterite and low-calcium eclogite varieties, as well as garnets of high-iron mantle pyroxenites are dominated. The presence of titanium impurities in many garnets indicates the possible diamond-bearing nature of some primary sources.

Reasons for the low productivity of the Bashkirian stage oil deposits on the southwestern slope of the South Tatar arch

Oil deposits of the Bashkirian stage of low-amplitude uplifts on the southwestern slope of the South Tatar arch are considered. It has been established that in the sections of the Bashkirian stage, only the upper two oil deposits are potentially productive. The reservoir rocks are composed of leached packstone-grainstone. The oil productivity of the upper oil reservoir is determined by the intensity of leaching of carbonate rocks and the nature of oil saturation, while the lower one is determined by the degree of oxidation of oils and the manifestation of secondary mineralization. Oxidation of oil from the lower reservoir oil deposit is associated with the penetration of peripheral stratal water enriched with sulphate ions and magnesium ions. Deposition of diagenetic calcite, dolomite and gypsum-anhydrite aggregates in previously formed leaching caverns leads to a decrease in porosity and connectivity within reservoir layers. For low-amplitude uplifts, there is a tendency for oil productivity to decrease as the proportion of diagenetic mineralization increases.

Ecological preferences of the Swiss pine (Pinus cembra L.) forests in the Gorgany Nature Reserve

Swiss pine (Pinus cembra L.) is a montane Carpathian (Alpine-Carpathian) species. The modern distribution of the Swiss pine is disjunct, the two isolated areas are located in western and central Europe (Alps) and the middle and high mountains of the Carpathians. The largest areas of Swiss pine in Ukraine are preserved in the Gorgany region at the altitude of 1250‒1450 m above sea level, where it forms the upper forest line. In the Gorgany Nature Reserve, P. cembra grows in the altitude range from 1070 to 1475 m ASL. The lower boundary, in the form of individual trees, descends to 1000 m ASL, and the upper boundary rises to 1585 m ASL. To define the ecological preferences of the Swiss pine, a series of route surveys were conducted and research sites (permanent forest monitoring plots, stationary research profiles, and stationary areas for the counting of natural forest regeneration) were established. The study of the plant communities with P. cembra on the southwestern slopes of the Dzhurdzhi tract showed the dependence of the forest species composition on the altitude above sea level. The forest stands quantitative composition and productivity are also significantly influenced by slope exposure. The proportion of P. cembra in the forests on steep slopes (30‒55°) of west and north-west exposure is relatively high (from 17.1% to 49.0%). Under other conditions, the proportion of P. cembra in the stand composition gradually decreases. Swiss pine is almost completely absent on the slopes of eastern and northern exposures except for rare single trees in Pinus mugo Turra scrub on northern slopes. The forests with P. cembra are typical of sunny slopes where the available sum of active temperatures ranges between 1000° and 1400° and the average ambient temperatures from -12.2°С to +16°С. The optimal environmental conditions for the relict species P. cembra in the Dovbushanski Gorgany region are on the western slopes with a steepness of 17‒55° and southwestern and northwestern slopes with a steepness of 35°‒42°. In terms of soil fertility, oligotrophic edaphotopes with moderate moisture are optimal for the growth of Swiss pine.

Добыча и обработка камня в средневековом городе на плато Эски-Кермен

Archaeological researches at the plateau of Eski-Kermen has recorded the traces of large-scale construction works carried out when the castle was built in the late sixth century and later, in the tenth and eleventh centuries, when several homesteads in the town quarters were demolished and small aisleless churches were erected at their places. The urban building was directly connected with stone-mining and stone-working. The most noticeable traces of ashlar-mining on the plateau appear in the sites between the three marches of the ascension road to the main gate of the town, which is carved into the bedrock of the south-western slope of the table mountain. The traces of work on the ashlars from the ruined buildings suggest the use of a pick, adze, simple and toothed chisel by local stonemasons. Mediaeval stonemasons also put special cross-shaped marks on the stones to indicate the batch of building materials prepared for the church construction. The living conditions in the castle and, later, in the town at the rocky plateau forced the local inhabitants to learn the skills of stone-working, as the mining and working of stone was in permanent need for the building and reconstruction of economic rooms, artificial caves, carving of graves, and making of household implements, such as the lids for pythoi and water-trough for livestock. Centuries-long life on the rocks probably developed a guild of professional stonemasons, or λάτομοι, in the town, who mined and dressed stone and passed on their skills from generation to generation. More complex work with stone, such as the making of architectural details and carving of decorations, wee plausibly done in specialised workshops (έργαλεΐον τους πελεκάνους) located outside the town, most likely near the quarries. The identification of the sites of these workshops in the south-western Crimea is a subject for the future research.

Geodynamic processes in the territory of the Svidovets mountain massif of the Ukrainian Carpathians (in the zone of the planned creation of a tourist and recreation complex)

The purpose of the research is a comprehensive analysis of various geodynamic natural processes on the territory of the Svydovets mountain massif of the Ukrainian Carpathians - the zone of the planned creation of a tourist and recreational complex for the development of a program for their further detailed study in the area of the planned activity (PА). The methodology includes a comprehensive analysis of the manifestation and course of dangerous geodynamic processes based on source information and individual studies of the authors. The Svydovets massif is located within the Central Synclinal Zone of the Carpathians, which is composed of Eocene and Oligocene chalk flysch. The highest part of the ridge with the southwestern and southern slopes and peaks Chorna Kleva (1720 m), Ruska (1678 m), Bratkivska (1788 m), Gropa (1759 m) is confined to the territory of the PA. The massif is characterized by a complex division of thrust structural slices of the Porkuletsky, Duklyansky and Chornohirsky nappes (covers). There are very steep north-eastern and gentle south-western slopes. The main forms of relief that characterize relict glacial relief are cirques, glacial valleys, rocky cirque ridges, steep rocky walls of cirques, moraine deposits, etc. On the southern and northern macroslopes of the Bratkivska Range, stone placers have been preserved from the Ice Age. Slope placers on the south-western macroslopes (areas of the Gropa, Ruska and Chorna Kleva mountains) are potentially dangerous for the formation of landslides and screes. Activities on the middle and lower slopes require special attention, where there is a possible negative impact during the construction of roads, felling and transportation of forest. Earthquakes, mudslides, landslides, debris flows, landslides, and avalanches are among the most dangerous processes on the territory of the PA. Earthquakes are of minor magnitude. Landslides and ossips are common on the northern and eastern slopes of the Svydovets massif, including on the watersheds and southwestern slopes of the Bratkivsky ridge. They are confined to slopes of considerable steepness (more than 35°) and occupy a small area. Small landslides with a volume of several tens of cubic meters of rock predominate, and rockfalls with fragments of 1-1.5 m in size. Landslide processes are widespread in the Ukrainian Carpathians, in particular within the PA in the Krosno tectonic subzone, which covers the latitudinal segment of the upper basin of the Chorna Tysza and the Yasinya syncline. Manifestations of avalanche activity on the Svydovets massif occupy one of the first places in the Ukrainian Carpathians along with the Chornohora and Borzhava ridges. The length of avalanches can be more than 1.5 km, and the volumes of avalanches - more than 400,000 m³. The Bratkivsky ridge is a non-avalanche active area, while the northern slope of the Svydovets massif and the Chorna Tysza valley are avalanche- dangerous. Considering that the PA territory covers mainly the southern slope of the Bratkivsky ridge, the avalanche danger is insignificant. Scientific novelty. The manifestation and activity of various dangerous geodynamic processes within the territory of the Svydovets massif - a zone of possible anthropogenic impact on the environment as a result of PA for the development of the ski resort - are analyzed in detail. Practical significance. The results of the research will help to the future developer of the ski tourist and recreational complex to develop a program for further detailed study of dangerous natural phenomena at the planned construction site, and can be partially used in the implementation of the Environmental Impact Assessment Report for PA. They also inform the public about the possible impact of PA on the environment.

The fault network in the southern foot of Rila Mountains, SW BulgariaThe fault network in the southern foot of Rila Mountains, SW Bulgaria

Southwestern slopes of Rila Mountain and northern parts of the Mesta graben are one of the least studied areas in terms of brittle tectonics. We carried out studies in the area around Bachevo and Dobarsko villages aiming to observe the fault zone network. The Bachevo fault zone is defined as Paleogene–Eocene Low-Angle Normal Fault that later underwent strike-slip and normal fault reactivation. The zone is an important tectonic boundary, separating the ca. 56 Ma Kapatnik granite from the Ograzhden Unit. Another important and possibly younger extensional zone is the Semkovo Fault. The relationships between the both zones are unclear. In terms of the Quaternary tectonics, it is important to differentiate between the Semkovo fault and the active Southeastern Rila Normal Fault. There are no data about Quaternary activity of the Bachevo fault zone.

Anthophila Fauna of Semi-desert and Mountain Ecosystems in Nakhchivan

As a result of long-term (2004-2021) studies conducted in the Nakhchivan, 405 species of Anthophila belonging to 6 families and 50 genera were registered. Vertical zones and plant formations of semi-desert and mountainous ecosystems are given according to literature data. The distribution of Anthophila in these ecosystems is given based on the results of many years of scientific research. Desert and semi-desert ecosystems, limited by elevations of 700-1200 m, occupy the majority of the territory. Divided into separate plains along the left bank of the Araz river. The plain is covered with desert, semi-desert, steppe plant formations, 102 species of Anthophila were found in this zone. The zone, partially expanding from west to east between altitudes of 1200-1500 m, is represented by low mountains. The dry mountain slopes of the zone are covered mainly with frigan vegetation. Analyzing the results of our research, it was found that 173 species of Anthophila are distributed in the low-mountain zone. The mid-mountain belt occupies an area at an altitude of 1500-2400 m above sea level. Here there are natural forests and agrocenosis of local form, located along the river valleys. The presence of semi-deserts, steppes and edge meadows created plant formations with a definite species composition. It has been established that 218 species of Anthophila are distributed in the mid-mountain zone. Four types of landscape are distinguished here, and a large number of species are calculated due to the presence of different biotopes. The high-mountain zone is mainly covered with subalpine, alpine meadows, surrounded by a narrow strip of heights of 2400-3906 m. Mountain-meadow, meadow-steppe types of vegetation create a transition between both zones. In the highland zone, 64 species of bees were represented. These species are more common in biotopes on the southwestern slopes of mountains, on sloping plains, in alpine and subalpine meadows.

Air pollution trapping in the Dresden Basin from gray-zone scale urban modeling

Abstract. The microscale variability of urban air pollution is essentially driven by the interaction between meteorology and urban topography, which remains challenging to represent spatially accurately and computationally efficiently in urban dispersion models. Natural topography can additionally exert a considerable amplifying effect on urban background pollution, depending on atmospheric stability. This requires an equally important representation in models, as even subtle terrain-height variations can enforce characteristic local flow regimes. In this model study, the effects of urban and natural topography on the local winds and air pollution dispersion in the Dresden Basin in the Eastern German Elbe valley are investigated. A new, efficient urban microscale model is used within a multiscale air quality modeling framework. The simulations that consider real meteorological and emission conditions focus on two periods in late winter and early summer, respectively, as well as on black carbon (BC), a key air pollutant mainly emitted from motorized traffic. As a complement to the commonly used mass concentrations, the particle age content (age concentration) is simulated. This concept, which was originally developed to study hydrological reservoir flows in a Eulerian framework, is adapted here for the first time for atmospheric boundary-layer modeling. The approach is used to identify stagnant or recirculating orographic air flows and resulting air pollution trapping. An empirical orthogonal function (EOF) analysis is applied to the simulation results to attribute the air pollution modes to specific weather patterns and quantify their significance. Air quality monitoring data for the region are used for model evaluation. The model results show a strong sensitivity to atmospheric conditions, but generally confirm increased BC levels in Dresden due to the valley location. The horizontal variability of mass concentrations is dominated by the patterns of traffic emissions, which overlay potential orography-driven pollutant accumulations. Therefore, an assessment of the orographic impact on air pollution is usually inconclusive. However, using the age-concentration metric, which filters out direct emission effects, previously undetected spatial patterns are discovered that are largely modulated by the surface orography. The comparison with a dispersion simulation assuming spatially homogeneous emissions also proves the robustness of the orographic flow information contained in the age-concentration distribution and shows it to be a suitable metric for assessing orographic air pollution trapping. The simulation analysis indicates several air quality hotspots on the southwestern slopes of the Dresden Basin and in the southern side valley, the Döhlen Basin, depending on the prevailing wind direction.

Trans-Japan Sea land-bridge disjunction: A case of vicariance in the subterranean genus Nipponasellus (Crustacea, Isopoda, Asellidae) in a large-scale biogeographical context.

This study examines nineteen phreatobiological hand pump samples collected in 20092010 in three separate areas of salmon river basins in the southern part of Primorye, in the Far East of Russia. For the first time, faunal groundwater patterns were assessed for the rivers of Eastern Manchuria, the Ussury River Basin and the rivers of the south-western slope of Sikhote Alin. A total of 164 species (including 32 stygobionts) belonging to the phyla Annelida, Mollusca and Arthropoda are first records of groundwater animals, and two of the stygobionts are described below as new species for Science. Nipponasellus sudzukhensis spec. nov. and N. matsumotoi spec. nov. are described and illustrated, and their taxonomic affinities with congeners are discussed. The morphology of male pleopod 2 of the genus Nipponasellus is re-examined using scanning electron microscopy (SEM), which revealed fine details of the pleopodal structures. The two new continental species of Nipponasellus were characterised by a distinct cannula completely immersed in ctenoid cuticular scales and the absence of a labial spur. Informal macrogroups were proposed based on the structure of the appendix masculina and an analysis of family distribution. The results of cladistic analyses revealed relationships between the proposed groups, but phylogenetic relationships within the Caecidotea-Proasellus group remain challenging. Common diagnostic characters of Nipponasellus showed that the group occupies an independent position close to the Caecidotea-Proasellus group rather than the Asellus-pattern sensu Magniez. Revised diagnosis for the genus Nipponasellus is given, including the two new species and the five previously described ones. The species diversity of East Asian stygobiotic asellid isopods is briefly reviewed to infer a biogeographic distribution pattern that emphasises the strict endemicity of members of the genus Nipponasellus. The intracontinental separation between continental Far East Asia and the Japanese archipelago highlights the biogeographic importance of the land-bridge in the Oligocene and raises questions about hypotheses explaining the (disjunct) distribution in East Asia, together with the circumstances preceding an ancient colonisation of the region.

FEATURES OF RELIEF OF THE BORZHAVA RIVER MIDDLE FLOW AREA AND THEIR CONNECTION WITH GEODYNAMICS AND SEISMOTECTONICS

With attraction of the newest (until 2010–2022 inclusive) geological-geophysical and geodetic data and geological-tectonic construction, the features of relief of the Borzhava River middle flow area (Ukrainian Transcarpathians) were analyzed, including peculiarities of the morphology of the river valley, their connection with the geodynamics and seismotectonics of the territory is traced. In the interval between Keretsky and Dovge villages the river flows in the valley of south – southeast direction between the southwestern slopes of the Folded Carpathians and northeastern slopes of Vygorlat-Guta volcanic ridge, tracing the near-surface localization of Transcarpathian deep fault zone geological structures (fault-suture, i.e. contact zones of the tectonic structures of the Transcarpathian depression and the Folded Carpathians). In the Dovge village river terns to the southwest and crosses the Vygorlat-Guta ridge in this direction in the interval to the Velyki Komyaty village, its valley here is associated with rupture discontinuities of the diagonal Borzhava fault zone. The place of terns of the Borzhava River in the Dovge village is connected with the area of junction of the structures of the Borzhava fault zone and the Transcarpathian fault-suture zone. The Onok height and the Velykyy Sholles volcanic ridge, which surround it from the southeast and east, are connected with influence of the diagonal Vynohradiv and meridional Oash faults. In the northeastern parth of studied area, under the mountain ranges of the Kuk – Palenyy Grun` ridges, a relatively deep (40–55 km) zone of seismic activity was discovered, it is related to the area of junction of the deep tectonic structures of the Transcarpathian and Oash fault zones, the first of which dips in the northeast direction under the Carpathians, and the second (its tilted subfault) dips in the eastern direction under the structures of the Solotvyno depression. Also regular, including the newest (2 perceptible earthquakes since the beginning of 2023) seismic activity (mainly at the depths of the pre-Neogene basement (2–6 km)) is demonstrated in the studied area (along with fault-block structures of the Transcarpathian trough and fold-thrust structures of the Folded Carpathians) by the structures Borzhava fault zone (orthogonal to the Carpathians, mini-graben in structure) and conjugated with it, the more submeridional Shalanky-Irshava (slightly sigmoid in plan) and Petrovo-Ardanovo faults. The genesis of the specified peculiarities of the relief and seismicity of the studied area is analyzed from the point of view of a combination of "alpine" (thrust-subduction of the crustal structures of the Transcarpathian depression and sedimentary strata of the modern Folded Carpathians to the northeast – the so-called multi-tiered "crocodile" tectonics), present "terrain" (shift to the east of the crustal structures of the Transcarpathian depression – northeastern end of the Alkapa terrane – superimposed, relatively low-amplitude process) and "asthenolitic" ("spreading" of convective flows from the asthenolite under Pannonia) components of late Neogene ("post-magmatic", up to 5–7 million years ago) and modern regional geodynamic process. Key words: Ukrainian Transcarpathians; Borzhava River valley; cross section; channel slope; faults; geodynamics; earthquake; seismotectonics.

Reduced complexity debris flow/flood hazard assessment at the southwestern slope of Mt. Omo, L’Aquila municipality, central Italy

Reduced complexity debris flow/flood hazard assessment at the southwestern slope of Mt. Omo, L’Aquila municipality, central Italy

Influence of atmospheric circulation on the spatial distribution of precipitation in the area of Sofia city

The study aims to reveal spatial distribution of precipitation in the area of Sofia city during the decade 2013 - 2022 and the influence of atmospheric circulation. Statistical methods and cartographic approach are the main tools in this research. The spatial distribution of precipitation is characterized by low amounts (560 mm) in the northern and northeastern parts of Sofia depression and high amounts (760 mm) in the southern part. The main factor for this spatial distribution of precipitation is atmospheric circulation. The relief has a significant modifying effect and affects precipitation through several mechanisms. The most important is the location of mountain slope relative to the main direction of transport of air masses. Leeward slopes receive less precipitation and windward slopes receive more. The second mechanism of influence is anthropogenic relief (high buildings), which is a positive relief form compared to the surrounding plane having respective windward and leeward slopes. This study revealed a third mechanism of relief influence on spatial distribution of precipitation. The large difference in the height of the mountains located south of Sofia creates a significant difference in the air temperature in Sofia depression during a transport of air masses from south and southwest. This is due to the stronger foehn effect of the higher mountain (Vitosha) compared to the foehn effect of the lower mountains (Lyulin, Lozenska Planina), which creates a tongue of higher air temperature northeast of Vitosha, which reaches the southern and southwestern slopes of Stara Planina. The higher temperatures in this tongue create stronger upward air movements, which in turn increase the amount of precipitation. Secondary, but still important factors that affect the spatial distribution of precipitation in Sofia region are the urban heat island and the increased content of aerosols in the air in and over the city.

Eocene palynoflora from the La Marcelina Formation, Patagonia, Argentina

Abstract Southern Patagonia contains several Eocene fossiliferous deposits that have only been superficially explored and studied. One of these corresponds to the La Marcelina Formation with outcrops in the south-western slope of the Deseado Massif, Santa Cruz Province, Argentina. No detailed palynological studies have been performed so far in this unit. Here we estimate the age, palaeoenvironment, and climatic conditions based on the analysis of terrestrially derived spores, algae cysts, and pollen grains. The recovered association supports an Eocene age and concurs with a mixed flora, including Gondwanan and Neotropical elements, dominated by Podocarpaceae, Nothofagaceae, and Proteaceae, and that probably developed under a temperate and humid climate. Overall, these results expand our understanding of the composition of Eocene floras from the highest latitudes of South America, as well as provide new evidence of past paleoclimates for the area.