Karst Processes Research Articles

МЕТОДИЧНІ ПРИНЦИПИ ГЕОФІЗИЧНИХ ДОСЛІДЖЕНЬ КАРСТОНЕБЕЗПЕЧНИХ ТЕРИТОРІЙ

The article is devoted to the analysis of the methodological principles of applying geophysical research methods in the study of karst-hazardous territories. The tasks that are posed in specialized studies of karst and geophysical methods for their solution are given. Four stages of specialized studies of karst-hazardous territories are identified: reconnaissance-methodological, prospecting, reconnaissance and monitoring. The set of geophysical methods for the development of these stages are determined. It is noted that a rational set of geophysical methods in the study of karst processes is determined for each individual natural environment (individual site). The possibility of performing field research by a separate geophysical method in this area, the presence of differentiation in rocks according to their physical properties which are used by a specific geophysical method and economic efficiency of the application of this geophysical method were taken into account. As an example, some results of geophysical studies carried out in the framework of the Lyubensky field of native sulfur are given.

ПРИМЕНЕНИЕ ГЛОБАЛЬНОЙ ЦИФРОВОЙ МОДЕЛИ РЕЛЬЕФА ASTER GDEM v.2 ДЛЯ ВЫДЕЛЕНИЯ РАЙОНОВ ВОЗМОЖНОЙ АКТИВИЗАЦИИ КАРСТОВЫХ ПРОЦЕССОВ НА ТЕРРИТОРИИ АРХАНГЕЛЬСКОЙ ОБЛАСТИ

ПРИМЕНЕНИЕ ГЛОБАЛЬНОЙ ЦИФРОВОЙ МОДЕЛИ РЕЛЬЕФА ASTER GDEM v.2 ДЛЯ ВЫДЕЛЕНИЯ РАЙОНОВ ВОЗМОЖНОЙ АКТИВИЗАЦИИ КАРСТОВЫХ ПРОЦЕССОВ НА ТЕРРИТОРИИ АРХАНГЕЛЬСКОЙ ОБЛАСТИ

Bedrock characteristics of selected covered karst sites in the Małopolska Upland

The article describes the nature of the bedrock in areas in the Małopolska Upland where landforms associated with covered karst processes occur. It seeks to find a relationship between geological structure and the potential for covered karst processes to develop. To this end, it includes a review of the literature on the geological structure of three areas in the mesoregions of Wzgór-za Opoczyńskie, Niecka Włoszczowska and Niecka Solecka. Two of the three sites are located in an area of limestone karst, and the third (located in Niecka Solecka) is an area of gypsum karst. All three sites were filled with sediment in the Holocene, but the forms being studied probably formed much earlier. The author also attempts to reconstruct the relief of the Mesozoic surface as digital terrain models. For this purpose, data was taken from geological drillings contained in geological maps of Poland and developed using GIS software. According to digital terrain models in the form of 3D views all three investigated sites are locat-ed in a depressions in the Mesozoic surface (on the slopes or bottom of the basin). That location and low thickness of impervi-ous deposits has caused that migration of underground water, which can affect karstified rocks with increased intensity.

РЕГИСТРАЦИЯ ГЕОДИНАМИЧЕСКИХ ПРОЦЕССОВ ФАЗОМЕТРИЧЕСКИМ МЕТОДОМ В СИСТЕМАХ ЛОКАЛЬНОГО ГЕОЭКОЛОГИЧЕСКОГО МОНИТОРИНГА

The article discusses the principles of processing recorded signals in local geoecological monitoring systems for the formation of phase images of geodynamic processes. The importance of continuous monitoring and control over the influence of geodynamic processes on natural resources and infrastructure engineering and technical objects in the process of their interaction is noted. It is shown that an effective option for local geoecological monitoring of these processes is the use of modern systems based on the use of geoelectric control methods, which are highly sensitive to changes in the electrical properties of the monitored objects. Along with the advantages of these methods, their disadvantages in controlling the amplitudes were noted, in particular, the complexity of solving monitoring problems in the presence of regular interference influences, changes in climatic factors and variations in the parameters of a specific measuring installation, in connection with which it is shown that the application of the method based on phase control is promising. higher sensitivity and noise immunity. A mathematical description of the phase–measuring method is given, structural diagrams and functional models are developed, which can be used for the practical implementation of measuring paths of systems for local geoecological monitoring of various geodynamic processes. The proposed approach was successfully experimentally tested in the process of studying a model of a phase–measuring measuring system for monitoring geodynamic karst processes in the coastal zone of Lake Svyato, Nizhny Novgorod region, which showed its high sensitivity to recording changes in phase images for extremely small geodynamic processes of natural and artificial origin.

ОЦІНКА ВПЛИВУ ФАКТОРІВ УРБАНІЗАЦІЇ НА НЕБЕЗПЕКУ АКТИВІЗАЦІЇ КАР-СТОВИХ ПРОЦЕСІВ У РЕГІОНАХ УКРАЇНИ

The article presents the analysis of the exogenous geological process activation hazards, namely karst, in the conditions of urbanization processes. The scale of geoecological problems is shown to be directly or indirectly determined by the scale of urbanization. The relevance of the research is associated with the study of the nature of changes in the expansion of karst rocks in regions with different levels of urbanization in the period 2001 – 2020. The main aim is to analyze the hazards of karst development in relation with the factors of urbanization processes in the regions of Ukraine based on the indicator method. The particular characteristics of the impact of urbanized territories on the initiation of natural disasters and geological hazards have been determined. The urbogenic load of the regions was assessed using determined and calculated earlier indicators of ecological and ecological-demographic urbanization. The assessment of the dependence between the hazard indicator of the spread of karst rocks and the indicator of ecological urbanization in the regional context has been carried out. It is shown that in the third part of the regions, the growing hazard levels of karst processes practically coincide with the growth of the ecological urbanization index. A nearly doubling of the area of karst terrains was noted during 2001 – 2020 in all administrative regions. The coefficient of expansion of karst territories for the specified period has been calculated. Four groups of regions were identified according to the increase in karst areas in comparison with the hazards of karst processes and the index of ecological-demographic urbanization. Expansion of open karst areas in the Transcarpathian, Odessa, Rivne, Kherson, Chernivtsi regions was noted. For this group of regions, a tendency to increase the areas of surface karst in accordance with an increase in the values of urbanization indicators has been established. This is due to the exploitation of natural territorial resources, changes in the nature of land use, depletion of vegetation cover, anthropogenic loads on the ground, and imbalances in the interaction of surface and underground waters in urbanized areas. Thus, the Ukraine’s regions with different urbogenic load are differentiated depending on the territorial indicator of the danger of karst terrains, as well as the dynamics of changes in the areas of karst rocks.

Оцінка закарстованості та стану гірничого масиву затопленого рудника № 2 Стебницького гхп “полімінерал” за результатами експериментального та матеріально-балансового моделювання

An analysis of the dynamics of flooding of rudnik N 2 Stebnitsky GHP “Polymineral”, restoration of groundwater levels, observed variability of chemical composition in mine workings, formation of natural hydrogeological stratification of the underground hydrosphere, development of karstological situation and assessment of its actual state. It is proved that after the failure that took place on March 15, 2020, there was an accelerated flooding of mine workings, underground karst cavities and saline deposits by September 2020, with gradual extinction and cessation of technogen-activity karst as flooding of supersalt deposits by August 2021 and formation equilibrium with salt rocks chemical composition of brines. The termination of the karst process is also proved on the basis of the results of experimental and material-balance modeling.

Late Cretaceous transtensional faulting of the Apulian Platform, Italy

This work focuses on the structural setting of a small area of the Murge Plateau, southern Italy, exposing Turonian bauxites and encompassing Upper Cretaceous carbonates of the Apulian Platform. By combining field geological and structural mapping with mineralogical and petrographic investigations of representative rock samples, we document the control exerted by Late Cretaceous, syn-sedimentary, high-angle faults and dilational fissures striking ca. N105E, N135E, N170E, and N45E. Altogether, these structural elements formed a few km-long, transtensional fault system along which karst-related shafts, dissolution caves, and sinkholes developed. Karst processes first affected the topmost limestone beds of the Valanginian-Cenomanian Bari Fm. Then, during Turonian, in a continental setting, cycles of terrigenous sediment deposition and weathering localized in the karst-related cavities, dilational fissures, and at the top of down-dropped fault blocks. Weathering of the Al–Si rich sediments formed bauxites made up of kaolinite, boehmite, goethite, hematite, and anatase mineral phases. The relative enrichment in kaolinite with respect to boehmite documented for the breccia and conglomerate matrix topping the bauxites is interpreted as due to lower degrees of weathering. Differently, the individual bauxite beds do not show any internal significant variation in terms of their mineral assemblages, but form angular unconformities due to syn-sedimentary faulting. The subsequent marine transgression also occurred under the influence of active tectonics, as displayed by growth folds at the bottom of the Conacian-Early Campanian Altamura Fm. The overall results of this study are in agreement with those previously reported for nearby areas of the Murge Plateau exposing Santonian limestone rocks of the Altamura Fm. Accordingly, we infer that Late Cretaceous transtensional faulting of the Apulian Platform was due to a far field stress state, likely associated to the orogenic processes that involved the northern edge of the Adriatic micro-plate.

CARACTERIZAÇÃO HIDROGEOQUÍMICA DOS AQUÍFEROS DA REGIÃO DA APA CARSTE DE LAGOA SANTA, MG

Estudo hidrogeoquímico foi realizado envolvendo a região da Área de Proteção Ambiental Carste de Lagoa Santa, 504km2, a norte do município de Belo Horizonte. As litologias aquíferas envolvidas foram a sequência pelito-carbonática da Formação Sete Lagoas, metapelitos da Formação Serra de Santa Helena e granito-gnaisses do Complexo Belo Horizonte. A primeira divide-se em Membro Pedro Leopoldo, inferior, encerrando calcários impuros, com intercalações pelíticas, e Membro Lagoa Santa, superior, contendo calcários puros. As águas são bicarbonatadas cálcicas, secundariamente bicarbonatadas mistas a sódicas, quando associadas ao embasamento e coberturas. As concentrações de Ca2+ e Si4+ foram fundamentais para a distinção entre as unidades aquíferas carbonáticas e não carbonáticas, permitindo também identificar águas mistas, elucidar sobre o meio de recarga e compartimentar horizontal e verticalmente o sistema aquífero. A heterogeneidade litológica conferida ao membro inferior levou a sua subdivisão em 4 tipos hídricos, enquanto as águas do Mb. Lagoa Santa são homogêneas, refletindo a sua homogeneidade litológica. A alta produtividade dos poços profundos deve-se à dissolução de porções rochosas mais puras e à localização próxima a falhamentos e de contato litológico entre os membros, enquanto nas nascentes é controlada pela intensidade dos processos de carstificação dos calcários mais puros do Membro Lagoa Santa.

ADVANTAGES OF NIEMFE METHOD IN GEOLOGICAL STATE MONITORING WHEN SOLVING APPLIED ENGINEERING PROBLEMS

Problem Statement and Purpose Finding effective methods for monitoring the state of engineering structures and geological conditions in their localization is an extreme­ly urgent issue today. The method of natural impulse electromagnetic field of the Earth (NIEMFE) is widely used for the solution of applied engineering-ecological, geological, geophysical and hydrogeological problems. The purpose of this work is to study the dynamics and the geological environment forecasting in conditions of increasing man-made load and prove the effectiveness of NIEMFE method in solving problems related to the violation of the engineering facilities operating conditions.Data & Methods Data from field observations conducted by employees of the De­partment of Geotechnogenic Safety and Geoinformatics of Ivano-Frankivsk National University of Oil and Gas were used to build the initial models. In particular, measure­ments by the NIEMFE method were performed on the territory of the school in the vil­lage Yunashkiv in the Rohatyn district and on the territory of the university building.Results The efficiency of using the NIEMFE method for solving geological engineer­ing problems is confirmed by the example of two diverse objects. The observations results obtained during the rocks stress-strain state study in the Yunashkiv village school in the Rogatyn district are considered. The NIEMFE method measurements allowed us to establish the stress-strain zones of the study area, which are related to the karst processes development. The analysis of the anomalies distribution and their intensities show that the territory is not stable and one should expect further karst manifestations and earth's surface and building deformation. The monitoring obser­vation results by the NIEMFE method are presented in order to track the dynamics of the change in the the IFNTUOG building state. The reason for the building damage, namely the design on the ancient river bed site, which led to the rocks strength loss due to the suffusion processes and the decomposition of the clay rocks underlying the foundation was identified. The influence of significant rainfall on the stress-strain state change of the studied territory was confirmed. It is proved that the NIEMFE method is a promising method for studying the rock mass stress-strain state in terms of determining the engineering structures stability and providing the deformation pro­cesses forecast.

Chronology of Middle Pleistocene Coastal Karst Evolution and Relative Sea-Level Changes in Mallorca

Lucia, G.; Polyak, V.J.; Gines, J.; Fornos, J.J.; Gines, A.; Asmerom, Y., and Onac, B.P., 2021. Chronology of middle Pleistocene coastal karst evolution and relative sea-level changes in Mallorca. Journal of Coastal Research, 37(2), 408–420. Coconut Creek (Florida), ISSN 0749-0208.Sea-level change affects the geomorphic evolution of littoral regions in multiple ways. In carbonate coastal regions, sea-level oscillations control the type and occurrence of karst processes such as mixing corrosion, speleothem deposition, and collapse. A variety of cave deposits exist above, below, and at sea level. Among these, the vadose speleothems can provide indirect constraints on maximum sea-level boundaries, record changes from vadose to phreatic phases as littoral groundwaters flood the caves due to sea-level rise, and document different coastal speleogenetic stages. Here, new U-series ages for speleothems from three sites along the eastern coast of Mallorca (Cala Falco, Dimoni, and Sa Ferradura) are presented and used to discuss the effects of relative sea-level oscillations upon coastal karst evolution between ∼1500 and ∼440 kyr before present. The paleo-speleothem record provides new timeframes for periods of vadose conditions allowing to place some relative sea-level constraints in the western Mediterranean, particularly for the Marine Isotope Stages 16 to 12. Periodic sea-level oscillations following glacial/interglacial cycles caused morphological changes within the paleo-caves. The sequences of collapsed karst features and vadose speleothems, coupled with geomorphological evidence and previous published sea-level records, support an interpretation for the occurrence of breakdown events during cold intervals following MIS 11, 9, and 7 sea-level high stands. Further collapses and dismantling of caves happened after MIS 5 high sea stands and throughout the Holocene.

The dolines of Campoli Appennino (Frosinone, Italy): a geo-historical overview

The spectacular karst morphologies of the area between Campoli Appennino and Alvito (Southern Lazio, Italy) represent an emblematic example of karst processes acting on different types of substrate. Hypogean forms are subordinated to epigean ones, with dolines as undiscussed leaders. Imposing and famous are the dolines of “Fossa Maiura” (also known as “Fossa Majura” or Fossa Majora”“) and “Il Tomolo”, around which the town of Campoli Appennino is built in a semi-circle, but are 8 the karst depressions with a diameter greater than 200 m (“main macrodolines”) in this area. These forms of landscape controlled the cultural and socio-economic aspects of this corner of Ciociaria. Starting from the second half of the 19th century, the hydrogeological, structural, stratigraphic and geomorphological features of the Campoli Appennino area, attracted the interest of geologists, allowing to recognize a “site of geological memory”. However, the geological heritage of this area worth greater visibility, as indicated by the poorly-developed geo-tourism, and for a greater dissemination, making the geo-morphological features more accessible and understandable, even for non-geologists.

The influence of geological fractures on karstic sinkhole development in eastern areas of Centurion, South Africa

Centurion is a fast developing area facing severe karstic sinkhole development. The area is predominantly underlain by fractured dolomite formations that include Oaktree, Monte Christo, Lyttelton, and Eccles of the Malmani Dolomite Group (~ 2600 and ~ 2500 Ma). Fractures of the underlying dolomite formations were investigated as one of the most influencing factors in karstic sinkhole formation using fieldwork mapping, petrology, and remote-sensing techniques (automated lineament extraction methods). Fieldwork results indicate that the study area has two prevalent fracture orientations trending N–S and ENE–WSW with average orientations of 178°/86° E and 073°/67° N. The fieldwork mapping results coincide with those acquired using remote-sensing techniques by automated extraction of lineaments from colour-shaded image and from four Sobel directional filtered images. Remote-sensing techniques indicate that there are extra two prevalent lineament directions; NE–SW and E–W in the study area and majority of the sinkholes develop in areas with high lineament density. Eccles, Monte Christo, and Oaktree dolomite formations exhibit a unidirectional fracture system while Lyttelton dolomite formation exhibit bidirectional fracture system. It is, therefore, concluded that (1) geological lineaments extracted using remote sensing and fractures present in the underlying dolomite formations play a significant role in controlling fluid circulation and thus influencing karstic processes such as dissolution, and therefore, (2) sinkhole development is primarily structurally controlled; however, it is exacerbated by anthropogenic activities due to the influence of water ingress.

Denaturing gradient gel electrophoresis and multi-SIR profiles of soil microbial communities from a karst doline at Aggtelek National Park, Hungary

Soils play an important role in the ecosystem of karstic landscapes both as a buffer zone and as a source of acidity to belowground water. Although the microbiota of karstic soils is known to have a great effect on karstification processes, the activity and composition of these communities are largely unknown. This study gives a comparative analysis of soil microbial profiles from different parts of a doline located at Aggtelek, Hungary. The aim was to reveal the relationships between the vegetation type and genetic fingerprints and substrate utilisation (multi-SIR) profiles of the soil microbiota. Soil samples were collected in early and late springs along a transect in a doline covered with different types of vegetation. Genetic fingerprints of bacterial communities were examined by denaturing gradient gel electrophoresis (DGGE) based on the 16S rRNA gene, along with multi-SIR profiles of the microbial communities measured by the MicroResp method using 15 different carbon sources. Genetic fingerprinting indicated that vegetation cover had a strong effect on the composition of soil bacterial communities. Procrustean analysis showed only a weak connection between DGGE and multi-SIR profiles, probably due to the high functional redundancy of the communities. Seasonality had a significant effect on substrate usage, which can be an important factor to consider in future studies.

Dynamic changes in the lower Gállego River (Ebro Basin, NE Spain) and their relationship with anthropic activities and the quaternary substrate

The lower Gállego River has been strongly degraded since the 1960s due to human activity (gravel mining, dump accumulation, channeling works), which has produced a deep channel incision. Although these human-driven processes are usually reported in fluvial bibliography, in this case, more complex results are observable. For instance, regarding the depth and incision rates, we observed no relationship between the most anthropically impacted areas and the sections with the deepest incisions; moreover, the deepening process continues 40 years after the human interventions ceased. The reason for this maladjustment is the role played by the exhumation of the underlying Pleistocene substrate, affected by the synsedimentary processes of karstification. The appearance of paleodolines filled with fine sediments on the incision bottom and sides is the main factor conditioning the continuity and magnitude of the process. Besides, these paleodepressions direct the river dynamics and course, thus favoring its widening when they appear and causing the development of a new riverbed (Qt13) while the 1960s floodplain (Qt12) is becoming an old terrace located between 5 and 11 m above the new alluvial bottom. There are no previous records about this kind of consequences in the regional fluvial dynamics.

Seismic monitoring system for landslide hazard assessment and risk management at the drainage plant of the Peschiera Springs (Central Italy)

The assessment of landslide hazards and design of strategies for managing the related risk have been widely studied topics in the scientific community due to the settlements, infrastructures and tourist and cultural heritage sites that may be threatened by deformations involving unstable slopes. Engineering geological and geophysical techniques have been recently integrated in multidisciplinary approaches to study gravity-induced slope instabilities and monitor their evolution.The slope that hosts the Peschiera Springs drainage plant (Central Italy) is involved in a mass rock creep process associated with deep karst dissolution. Due to the importance of this infrastructure, which provides water to the Rome aqueduct, an accelerometric network was installed in 2008, and a nanoseismic array was added in 2014. In this paper, data recorded by the nanoseismic array were used to locate 397 microseismic events related to the slope instability process, distinguished into two types with different waveforms: 16 failures and 381 collapses. The failures were distributed throughout the slope, while the collapses exhibited two spatially separate clusters below the groundwater level, at a depth where karst processes produce cavities. The clusters were analysed as two distinct microseismic sources characterised by specific frequency-magnitude curves of events that describe their attitude to produce events of different magnitudes. Regarding the accelerometric network, an automated procedure was developed for quickly analysing the seismic records, which include signals from teleseisms and near- to far-field earthquakes that can induce deformation in the landslide-involved slope.The results obtained by the two seismic monitoring systems were integrated with the aim of implementing a landslide hazard matrix based on the statistical frequency of the occurrence of such events and their probability of exceedance during a reference period, providing a useful tool for managing the related landslide risk.

Time series analysis of karst breakdown development on the potassium salt deposit areas within Precarpathian region

The work is devoted to the analysis of karst breakdown development over time within the area of the Kalush-Golynske and Stebnytske potassium salt deposits. A study of the relationship between the development of karst breakdowns with the factors influencing their development in natural conditions and in the conditions of natural-technogenic systems is presented. Time series of karst breakdowns in the Kalush-Golynske and Stebnytske deposits of potassium salt were selected for the investigation. The time series reflect the number of formed failures of the earth’s surface due to karst processes. Climatic (average annual temperature and annual precipitation), heliophysical (solar activity), seismic (number and energy of earthquakes), hydrogeological (groundwater levels) were chosen as such factors. Breakdown phenomena, which are included in the time series of their longterm dynamics, are associated with different hydrodynamic zones of karst processes. For these zones, the indirectness degree of the influence of the selected for the analysis factors is different and the meteorological parameters are more effective in the supply zone, seismic factors work in all zones. Statistical methods such as correlation analysis, calculation of autocorrelation and cross-correlation functions, spectral analysis are used for the analysis of the time series. Statistical regularities in the series of karst breakdown development for Kalush-Golynske and Stebnytske potassium salt deposits and between the selected natural time factors and karst series have been established, which allows asserting the indirect influence of natural component of karst activation. The presence of periodic components in the long-term series of karst breakdowns should be associated with the natural factors that indirectly activate karst processes. These factors should be investigated and taken into account when creating temporal prognostic models for the development of karst breakdown processes within the deposits of potassium salt of Precarpathia.

The Construction of Cultural Consensus Models to Characterize Ethnogeological Knowledge

Limited research interest has been focused on the understanding of culturally framed geology knowledge in comparison with more mature ethnosciences such as ethnobotany or ethnogeography. Ethnogeology is the scientific study of human relationships with and knowledge of the Earth system, generally investigated within the context of a specific culture, through the implementation of field geologic and field ethnographic methods. The purpose of this paper is to present the use of cultural consensus analysis for the exploration of culturally framed knowledge of geological processes. We used rapid assessment methods from the discipline of field ethnography with local cultural consultants, to construct a cultural consensus questionnaire about karst processes and riverine geomorphology in Puerto Rico (PR) and the Dominican Republic (DR). We employed the results from structured interviews and identified common themes that we organized as a cultural consensus model (CCM). Our results indicate a CCM for the knowledge domain of karst processes and riverine geomorphology that is shared by inhabitants of karst regions in DR and PR, which constitutes a reliable system of local ethnogeologic knowledge. Conceptual key elements of the model include use of metaphors and analogies to describe geomorphic processes and speleothem. We discuss the use of rapid assessment and cultural consensus analysis as a method for ethnogeological research, and the implications for place-based geoscience education, participatory research, and geoheritage.

Apulian Karst Springs: A Review

Apulia (southeastern Italy) is an elongated peninsula, located between the Ionian and the Adriatic seas, characterized by a semi-arid climate. It is an almost entirely karst region, with very limited availability of surface freshwater resources. The groundwater, the only water resource of Apulia, is affected by severe pollution problems related to both antropogenic and seawater intrusion phenomena. This is further exacerbated by the strong tourist vocation of the area, with heavy pressure by touristic water demand, especially during summertime. The Apulian geography and related freshwater problems require a thorough knowledge about karst processes, with specific regard to springs and aquifers. Despite this, in recent decades the attention on regional karst water resources was quite limited, and there is the huge need to implement new research in this field, aimed at reaching a better understanding of the Apulian karst. In this work we present a review on the main Apulian karst springs, divided in the three main sub-karst areas (Gargano, Murge, and Salento), based upon critical revision of the existing scientific literature. The aims are to build a database of known karst springs, and, further, to highlight the widespread and remarkable presence of karst phenomena in the region.

Thermal Remote Sensing for Water Outflows Detection and Determination of the Role of Lineaments in Underground Hydrodynamics of Evia Island, Central Greece

The coastal karst system of Evia Island is developed due to the extended presence of carbonate formations, discharges into the sea either at the coastal zone or via submarine springs, having a direct relation to the tectonic system of the area. Thermal infrared remote sensing has been proved its capability in monitoring thermal differentiations of coastal water plumes. This work aims to locate the freshwater outflows through remote sensing and specific with the use of Landsat’s 8 thermal images and to reveal how the lineaments of the area control this karstification process. L8 contains two thermal bands (Band 10, high gain and Band 11, low gain) with resolution 30m which record the scattering of infrared radiation from the sea surface. Spectral Band 10 was selected due to the high gain characteristics which provide more suitable radiometric resolution (sensitivity). Finally, combing thermal images with geological maps, sea surface temperature (SST) maps have been created.

The Assessment of the Influence of the Hydrogeological Regime of Rivers on the Conditions of the Decentralized Water Supply in Karst Areas

The article shows that the level of river flow has a significant impact on the development of destructive karst-suffusion processes. Karst water exchange systems have a high natural and anthropogenic vulnerability of groundwater resources and low ability to self-purify. The water quality of decentralized water supply sources largely depends on the presence of active karst processes. The studies were conducted in the territory of the village of Chud Navashinsky district of the Nizhny Novgorod region, subject to karst-suffusion processes. The hydrogeological characteristic of the study area is determined; the generalized characteristics of the seasonal fluctuations of the river flow are calculated. The development of karst processes in the study area is assessed. It has been determined that during the year, the period of spring flood on the Oka River has the greatest impact on landfall formation. It has been established that unauthorized dumps of municipal solid waste located in the karst zones of the Chud village affect the chemical composition and increase the total salinity of groundwater used for decentralized water supply. The results can be used to improve the regional model for assessing the resources of vulnerability and protection of groundwater and predicting the activation of destructive karst processes in the karst zone of the Oka River basin, Nizhny Novgorod Region.