Gravitational Processes Research Articles

Геоморфометрический анализ цифровой модели рельефа Верхнеангарской котловины для выявления и оценки опасных гравитационных процессов

The article presents the results of a comprehensive geomorphological analysis of the relief types of the Verkhneangarskaya depression (Lake Baikal basin) for geoinformation diagnostics of dangerous gravitational processes. The physical and geographical characteristics of the study area are given, tectonic and geological features of relief formation are designated. For metric assessment and subsequent mapping of the relief in the ArcGIS software environment, a digital elevation model (DEM) of the study area and raster coverages of morphometric parameters of slope and aspect were created on the basis of isolines and elevation marks of the topographic base at a scale of 1:100 000. For geomorphometric analysis of the relief model, five representative polygons were selected that characterize similar relief types of arched-block mountains and have the same physical and geographical conditions for the formation and development of gravitational processes. To visualize each polygon, slope and aspect mapping was performed, and a space image was presented. In the process of analysis and geomorphological interpretation of representative polygons, the planned-altitude metric parameters of relief types with similar morphometric characteristics were established, contributing to the formation and development of dangerous gravitational processes and determining the conditions and risks of economic activity in mountainous areas: high-mountain erosion-exaration, high-mountain denudation-erosion, mid-mountain erosion-denudation, mid-mountain denudationerosion, low-mountain denudation.

GRAVITATIONAL GEOLOGICAL PROCESSES (KARST)

The article presents karsts, as one of the gravitational geological processes, developing in rocks (limestone, dolomite, gypsum, anhydrite, sodium and potassium salts) dissolving in natural surface and groundwater. For the first time, an attempt was made to study karsts, changes in hydrogeological conditions during their development and the influence on internal and external hazardous geological phenomena. The main purpose of this article is to draw attention to the need for further study of the Dvin earthquake source, associated with the possible collapse of underground voids (in this case, karst halls) characteristic of this territory.

The effect of tectonic boudinage and folding in a subducted mélange of the Alpine orogenic belt (Zermatt–Saas Zone, Italian Western Alps)

The Zermatt–Saas Zone is an eclogite-facies meta-ophiolite unit representing the fossil oceanic lithosphere of the Jurassic Tethys. In the Italian Northwestern Alps, the Zermatt–Saas Zone includes a chaotic rock unit, or mélange, c. 40 m thick, interposed between serpentinites and calcschists. The mélange consists of decimetre-scale ultramafic layers and boudins embedded in a serpentine + carbonate-rich matrix showing a block-in-matrix fabric. The mélange has the same Alpine tectonometamorphic evolution as the surrounding rocks, starting with a prograde path developed under high-pressure (HP) conditions followed by a retrograde path during exhumation. The kinematic and metamorphic relations between inside- and outside-boudin foliations indicate that boudinage and shearing developed during the prograde HP path. Fluid–rock interaction enhanced shearing and focused ductile and brittle–ductile deformation along lithological contacts between rigid blocks and boudins and flowing carbonaceous matrix. Despite a pervasive orogenic evolution, the primary tectonosedimentary features of the mélange are still recognizable in some outcrops and are attributed to an intra-oceanic (Jurassic) setting characterized by mass-transport processes. The present-day fabric of the studied mélange unit thus results from the superimposition of the Alpine processes, responsible for fluid-assisted stratal disruption and mixing in the subduction channel, on the original stratigraphy formed during intra-oceanic gravitational processes. Supplementary material : Supplementary figures and tables are available at https://doi.org/10.6084/m9.figshare.c.6924080 Thematic collection: This article is part of the Ophiolites, melanges and blueschists collection available at: https://www.lyellcollection.org/topic/collections/ophiolites-melanges-and-blueschists

Combined Methodology for Rockfall Susceptibility Mapping Using UAV Imagery Data

Gravitational processes on cut slopes located close to infrastructure are a high concern in mountainous regions. There are many techniques for survey, assessment, and prognosis of hazardous exogenous geological processes. The given research describes using UAV data and GIS morphometric analysis for delineation of hazardous rockfall zones and 3D modelling to obtain an enhanced, detailed evaluation of slope characteristics. Besides the slope geomorphometric data, we integrated discontinuity layers, including rock plains orientation and fracture network density. Cloud Compare software 2.12 was utilised for facet extraction. Fracture discontinuity analysis was performed in QGIS using the Network GT plugin. The presented research uses an Analytical Hierarchy Process (AHP) to determine the weight of each contributing factor. GIS overlay of weighted factors is applied for rockfall susceptibility mapping. This integrated approach allows for a more comprehensive GIS-based rockfall susceptibility mapping by considering both the structural characteristics of the outcrop and the geomorphological features of the slope. By combining UAV data, GIS-based morphometric analysis, and discontinuity analysis, we are able to delineate hazardous rockfall zones effectively.

Conservative binary dynamics from gravitational tail emission processes

Conservative binary dynamics from gravitational tail emission processes

Little Ado about Everything: ηCDM, a Cosmological Model with Fluctuation-driven Acceleration at Late Times

We propose a model of the Universe (dubbed ηCDM) featuring a controlled stochastic evolution of the cosmological quantities that is meant to render the effects of small deviations from homogeneity/isotropy on scales of 30–50 h −1 Mpc at late cosmic times associated with the emergence of the cosmic web. Specifically, we prescribe that the behavior of the matter/radiation energy densities in different patches of the Universe with such a size can be effectively described by a stochastic version of the mass–energy evolution equation. The latter includes, besides the usual dilution due to cosmic expansion, an appropriate noise term that statistically accounts for local fluctuations due to inhomogeneities, anisotropic stresses, and matter flows induced by complex gravitational processes. The evolution of the different patches as a function of cosmic time is rendered via the diverse realizations of the noise term; meanwhile, at any given cosmic time, sampling the ensemble of patches will create a nontrivial spatial distribution of the various cosmological quantities. Finally, the overall behavior of the Universe will be obtained by averaging over the patch ensemble. We assume a simple and physically reasonable parameterization of the noise term, gauging it against a wealth of cosmological data sets in the local and high-redshift Universe. We find that, with respect to standard ΛCDM, the ensemble-averaged cosmic dynamics in the ηCDM model is substantially altered by the stochasticity in three main respects: (i) an accelerated expansion is enforced at late cosmic times without the need for any additional exotic component (e.g., dark energy), (ii) the spatial curvature can stay small even in a low-density Universe constituted solely by matter and radiation, (iii) matter can acquire an effective negative pressure at late times. The ηCDM model is Hubble tension–free, meaning that the estimates of the Hubble constant from early- and late-time measurements do not show marked disagreement as in ΛCDM. We also provide specific predictions for the variance of the cosmological quantities among the different patches of the Universe at late cosmic times. Finally, the fate of the Universe in the ηCDM model is investigated to show that the cosmic coincidence problem is relieved without invoking the anthropic principle.

Reasons for Low Fraction of Arctic Stratospheric Cloud in 2014/2015 Winter

AbstractPolar stratospheric clouds (PSCs) play a key role in Arctic amplification and stratospheric ozone destruction in polar regions. In this paper, we used the CALIPSO data to analyze the spatiotemporal distribution of Arctic PSCs from 2006 to 2021. We found that Arctic PSCs mainly appear in December, peak in late December and early January, disappearing in late February and early March. PSCs can extend from heights near the tropopause to over 25 km. However, there is the lowest fraction of PSCs in the 2014/2015 winter. This study found that the temperature in the 2014/2015 winter was warmer than the 15‐year average temperature, with the lowest temperature slightly below the PSCs formation temperature of about 5 K. The formation of the Ural blocking high accompanied by the poleward propagation of the planetary wave caused a sudden stratospheric warming (SSW) event on 3 January 2015, during which the warm air entered the polar vortex and divided it into two lobes. Additionally, a reduction in SO2 column mass density before the SSW event resulted PSCs occurring with a frequency of only 0.148 and dissipating rapidly in December. Moreover, the concentration of H2O and HNO3 in the gravitational settling process of PSCs decreased by 20–50%, the reduction of condensation nuclei made PSCs with the highest frequency of 0.074 in February appear briefly and then disappear. The chemical and dynamic analysis of PSCs formation is needed to further understand the spatiotemporal distribution of Arctic PSCs and to better predict future Arctic amplification and ozone destruction.

Gravitational resedimentation as a fundamental process in filling fjords: Lessons from outcrops from a late Palaeozoic fjord in Namibia

AbstractThe stratigraphic architecture of fjords is complicated due to the delicate interplay between ice dynamics, sediment supply, relative sea‐level fluctuations and slope failures. Glaciogenic sediment is prone to failure and to be carried downslope to the fjord floor through the entire spectrum of mass movements and subaqueous density flows, as the unstable paraglacial submarine landscape moves towards stability. Palaeofjords formed by Gondwanan glaciers during the late Palaeozoic Ice Age contain a compelling record of gravitational resedimentation in fjord depositional systems. This paper showcases the geomorphology and depositional history of a glacial cycle in the Orutanda fjord in north‐western Namibia as an example of an overdeepened fjord basin fill dominated by products of subaqueous gravitational processes. During glaciation, the Orutanda glacier carved a 20 km long by 3.7 km wide glacial trough that embodies an overdeepened basin. Ice thickness during terminal glacial occupation of the fjord is estimated to had been up to 200 m based on the fjord geomorphology. The progressive retreat of the tidewater glacier, concomitant with marine flooding, increased accommodation space in the overdeepened basin during deglaciation. During this stage, proglacial sedimentation through iceberg rafting and settling of turbid plumes was outpaced by intense paraglacial downslope resedimentation of glacially‐transported debris. Successive failures from the fjord walls and downslope resedimentation resulted in coalescing debrite–turbidite lobes on the fjord floor. Slide deposits, composed entirely of deformed debrites and turbidites, indicate that these resedimented facies were prone to renewed mass wasting. As the Orutanda glacier melted, the fjord experienced the axial progradation of a fjord‐head delta registered only by turbidites and slide deposits derived from its collapse. The Orutanda fjord sheds light on the relevance of paraglacial mass wasting in overprinting glaciogenic deposits. This insight is key to understanding the role of glaciers versus non‐glacial processes in producing the glacial deep‐time record.

Formation processes, fire use, and patterns of human occupation across the Middle Palaeolithic (MIS 5a-5b) of Gruta da Oliveira (Almonda karst system, Torres Novas, Portugal).

Gruta da Oliveira features a c. 13 m-thick infilling that includes a c. 6.5 m-thick archaeological deposit (the "Middle Palaeolithic sequence" complex), which Bayesian modelling of available dating results places in MIS 5a (layers 7-14) and MIS 5b (layers 15-25), c. 71,000-93,000 years ago. The accumulation primarily consists of sediment washed in from the slope through gravitational processes and surface dynamics. The coarse fraction derives from weathering of the cave's limestone bedrock. Tectonic activity and structural instability caused the erosional retreat of the scarp face, explaining the large, roof-collapsed rock masses found through the stratification. The changes in deposition and diagenesis observed across the archaeological sequence are minor and primarily controlled by local factors and the impact of humans and other biological agents. Pulses of stadial accumulation-reflected in the composition of the assemblages of hunted ungulates, mostly open-country and rocky terrain taxa (rhino, horse, ibex)-alternate with interstadial hiatuses-during which carbonate crusts and flowstone formed. Humans were active at the cave throughout, but occupation was intermittent, which allowed for limited usage by carnivores when people visited less frequently. During the accumulation of layers 15-25 (c. 85,000-93,000 years ago), the carnivore guild was dominated by wolf and lion, while brown bear and lynx predominate in layers 7-14 (c. 71,000-78,000 years ago). In the excavated areas, conditions for residential use were optimal during the accumulation of layers 20-22 (c. 90,000-92,000 years ago) and 14 (c. 76,000-78,000 years ago), which yielded dense, hearth-focused scatters of stone tools and burnt bones. The latter are ubiquitous, adding to the growing body of evidence that Middle Palaeolithic Neandertals used fire in regular, consistent manner. The patterns of site usage revealed at Gruta da Oliveira are no different from those observed 50,000 years later in comparable early Upper Palaeolithic and Solutrean cave sites of central Portugal.

Raincloud conditioning by thunder

AbstractThis article considers the role of thunder in the production of rain by gravitational processes. A previous numerical work has shown that a thunder event consisting of four consecutive thunderclaps can alone produce small but significant droplet growths in a lean cumulus cloud in less than 2 s. Here we consider, also numerically, the coalescence effects produced by both thunderclaps and gravity in a cumulus congestus cloud that had more than four times the liquid content of that lean cloud. Those effects are studied separately and in tandem, using the same set of assumptions. Therefore, the results presented here provide a basis for the comparison of the effectiveness of each type to produce droplet growth in thunderclouds. For thunder alone, these results show that a small number of thunderclaps can in less than 2 s produce mean size growths larger than 50%. For gravity alone, it is found that after 60 s, the longest time considered, gravitational coalescence increases the mean diameter of the original droplet size distribution by 20%. The tandem study considers the effects produced by gravitation on the droplet size distribution that resulted after the original distribution was modified by four or five thunderclaps. Significant increases are found in both cases. For four claps it was found that the mean size increased by 71% in 60 s. The corresponding growth for five claps was slightly larger than 100%. These substantial increases also show that the growths produced by the thunderclaps are not simply additive, but significantly accelerate those produced by gravitation. This acceleration implies that the droplet size growths produced by thunderclaps can substantially decrease the time required by gravitational coagulation to produce raindrops in rainclouds.

Physics of gravitational processes as a key to understanding the properties of Achimov deposits

The article is devoted to the development of a methodology for predicting the properties of Achimov reservoirs based on cause-and-effect relationships such as the source of shelf sedimentary material, the geometry of clinoforms and the distance of alluvial fans to the slope. The technique was developed on the basis of physical laws, namely the conditions of disturbance of the gravitational equilibrium of sediments on the shelf edge – the moment of the beginning of the removal of sedimentary material and the process of cone formation caused by the deposition (braking) of sediments on the bottom of the basin. The methodology includes two stages for step-by-step theoretical justification and ease of understanding. At the first stage, the problem of disturbing the gravitational equilibrium of shelf sediments depending on the geometry of the clinoforms is solved. At the second stage, the problem of dependence of the distance of the blades on the slope and the properties of promising objects is considered. Based on theoretical concepts, the main conclusions about the dependence of the characteristics of alluvial fans (properties and volume of sandstone) on the geometric parameters of clinoforms and on the distance to the slope are outlined, and a complex parameter characterizing the properties of promising objects is derived. The methodology developed by the author makes it possible to predict, compare and rank Achimov objects according to their prospects both within one formation and as a whole in one or several fields.

FEATURES OF GEOMORPHOLOGY STRUCTURE OF THE GNIVAN GRANITE QUARRY (VINNYTSIA REGION)

The Hnivan granite quarry is located in Vinnytsia district of Vinnytsia region. Geomorphologically, territory belongs to the western edge of the Dnieper Upland. Geostructurally, the quarry is located on the western edge of the Ukrainian shield, within the Podilsky megablock. Since the beginning of development, 7 rock horizons have been fully opened. As of today, the 8th horizon is being developed, and the development of the 9th horizon is planned in the future. The Hnivan quarry is a deep polygonal trapezoidal quarry in plan with many steps in profile. Morphometric characteristics of the Hnivan quarry and dump complex: the maximum length from north to south (including dumps of overburden strata) is 1 800 m; the maximum length of the quarry pit from north to south is 1 400 m, the maximum width from west to east is 900 m. The absolute heights within the mining are 230–255 m, the absolute height of the mine floor is 130 m. The depth of the quarry pit is currently about 105 m. The bottom is 97 meters below the level of the Southern Buh river. Quarry landforms are divided into produced relief forms, caused by anthropogenic denudation and bulked relief forms, created as a result of anthropogenic accumulation. The produced relief of the Hnivan quarry is represented by the bottom and walls. The bottom has a complex geometric shape of an elongated polygon from north to south. It consists of the bottom of the seventh developed horizon and the eighth horizon, where mining operations are carried out. Between these horizons, there is a step 15 m high. The surface of the bottom is flat, there are no internal dumps. The walls of the quarry are characterized by a multi-step shape in profile. They are approximately the same in height, steepness and nature of the processes. The structure of the walls in the upper parts, which are represented by ledges of overburden horizons, is different. The ancient steps of the mine walls are significantly disturbed by weathering, water erosion and gravitational processes. The produced relief forms of the quarry are represented by overburden dumps and processing plant dumps. All of them are located outside the quarry and are external dumps. Dumps of overburden strata are recultivated - stable and artificially forested. This example of carrying out reclamation works of a part of the quarry and dump complex can be a model for the improvement of anthropogenically disturbed territories. Key words: granite quarries; geomorphological structure; excavated relief; heaped relief; Hnivan.

The lower Barra Velha formation (Aptian) in the Atapu field, Santos basin: Geological model for a pre-salt succession

The lower Barra Velha formation (Aptian) in the Atapu field, Santos basin: Geological model for a pre-salt succession

ANTHROPOGENIC TRANSFORMATION OF TERRAIN IN THE NORILSK INDUSTRIAL DISTRICT

The scale of anthropogenic terrain transformation within the Norilsk industrial region was quantified and a classification of its consequences has been elaborated. The work is based on the results of 2021 expeditionary geomorphologic studies, interpretation and analysis of remote sensing materials and digital elevation models. It has been established that the total area of direct terrain transformation during the territory development was about 122,4 km2, and that of indirect transformation - 23,6 km2. The volume of anthropogenic landforms is at least 1,8 billion m3; accumulative forms account for 93% of the area and 72,6% of the volume of direct landform transformations. The types of anthropogenic landforms were identified, it was found that the largest area is occupied by embankments for industrial development and tailings, and the largest volume is characteristic of slope dumps. Indirect terrain transformation is mainly activation of gravitational processes, linear erosion, suffusion, thermokarst, heaving and deflation. The mass displacement of slope dumps by landslides or stone glaciers are the most dangerous for infrastructure facilities. Separate areas of indirect transformations are mainly limited to the lacustrine-alluvial lowlands and the bottoms of river valleys. Among them, the largest area (up to 20 km2) is occupied by segments of river valleys affected by spills of oil products and tailings. It has been established that the accumulation of pollutants in river valleys of the Norilsk industrial region occurs within the internal deltas and ice glades where the longitudinal slope decreases. Three stages of anthropogenic development of the territory are distinguished (I - 1920-1953; II - 1953-1986; III - 1986-2021); the most significant increment in the area of anthropogenic terrain occurred from 1953 to 1986. The average rate of anthropogenic terrain area increment over the past 36 years amounted to 0,81 km2/year. The highest rates of area growth are characteristic of the Kayerkan and Talnakh regions, which is associated with ongoing mining.

Landslide susceptibility evaluation in Alpine environment: 1. 3D Finite Element modeling of the Ruinon (IT) case study

Landslide susceptibility evaluation in Alpine environment: 1. 3D Finite Element modeling of the Ruinon (IT) case study

Fluvial reorganization in mountain landscapes: preliminary analysis of the interaction between gravitational and fluvial processes in Serra da Prata, coast of Paraná (southern Brazil)

Corridas de lama e detritos são eventos que podem resultar em expressivas mudanças nos sistemas fluviais. Apesar desses eventos serem frequentemente relatados na literatura, sobretudo, na Serra do Mar, a abordagem da interação processos gravitacionais e processos fluviais ainda é tema em aberto no campo da Geomorfologia. Assim, considerando a Serra da Prata (litoral do Paraná) como recorte de estudo, objetiva-se analisar as reorganizações fluviais impostas pelas corridas de lama e detritos ocorridas em março de 2011, a partir da análise temporal da forma em planta de três canais fluviais (rios Jacareí, Tingidor e Santa Cruz) obtidos por dados de sensoriamento remoto. Para tal, foi proposta uma classificação de processos de reorganização fluvial considerando a interação entre processos fluviais e gravitacionais. Foram identificados 12 pontos de reorganização fluvial, divididos entre os processos de formação de canais (7), corte/desvio (4) e captura (1). O rio Jacareí apresentou o maior número de pontos de reorganização fluvial (7). Os processos de formação de canais e corte/desvio ocorreram tanto em porções elevadas do relevo (com alta declividade) como em trechos da planície de inundação. O processo de captura ocorreu na porção média das vertentes da Serra da Prata em função do rompimento de margens pelas corridas de lama e detritos. Recomenda-se que sejam realizados estudos visando identificar estes processos em outros rios da Serra do Mar afetados por corridas de lama e detritos, bem como os debates sobre os conceitos empregados para analisar estas mudanças resultantes da interação de processos gravitacionais e fluviais.

MODELING OF THE CORIUM AND METALS – COOLERS INTERACTION IN A CORE CATCHER OF A LIGHT WATER REACTOR

The core catcher is one of the mandatory elements of the reactor safety system, which prevents the release of reactor core materials in a severe accident. The core catcher is steel vessel filled with sacrificial materials (SM) and forming a tank where a corium melt coming from the core is formed. The trap is a steel body filled with sacrificial materials (LM) and forming a vessel where a corium bath is formed coming from the core. The melt formed in the core catcher is cooled by heat removal to the cooling water through the shell of the steel vessel, as well as by water supplied directly to the surface of the melt after the dissolution process of the SM in corium (gravitational inversion). The delay in the water supply to the melt is associated with the features of the component structure of corium and its interaction with water (the formation of explosive hydrogen and the possibility of its detonation, as well as the threat of a steam explosion). However, a certain amount of time is spent on the implementation of gravitational inversion, and it is desirable to start the water supply to the melt immediately at the moment when the corium enters the core catcher due to the danger of the system going beyond the permissible limits (the beginning of boiling of uranium dioxide) due to decay heat in the corium. In this regard, the authors have an idea – to use a fusible metal for additional cooling of the surface of the corium in order to organize heat removal and reduce the temperature of the corium in the period before the end of the gravitational inversion process. The article presents the results of modeling the interaction of corium with candidate low-melting metals – coolers. The modeling was conducted using the ANSYS software package. As a result of the conducted work, the time for which each of the considered cooling metals will reach the points of phase transitions of melting and boiling is determined. The analysis of the results allowed us to draw appropriate conclusions about the possible practical implementation of the proposed method of cooling corium.

Geomorphology of Abandoned Underground Slate Mines in Czechia

We conducted one of the first complex geomorphological investigations of underground abandoned slate mines in Czechia, Central Europe. Sixty types of subterranean geomorphic forms were described from 114 abandoned underground slate mines in the Nízký Jeseník Upland. The forms, evaluated according to their type, scale, frequency, and fragility, are independent of each other or embedded. Their cascades occur in large multilevel mines affected by fluvial and gravitational processes. Analysis of the microforms revealed mine pearls enriched with titanium, calcareous soda-straw stalactites, amorphous calcareous-sulphurous piles, and quartz veins. Forty-seven of the identified mines were affected by gravitational failures. Four-year measurements of cracks revealed both negligible oscillations and distinct displacement of rock blocks up to 4 mm. The range of described geomorphic forms together with identified cascades and measured crack displacement point to rich geodiversity and high dynamics within the abandoned mines. Compared to other subterranean geosystems, the geomorphology of abandoned underground slate mines remains poorly investigated, although knowledge of subterranean geomorphic systems is crucial for future natural evaluation, risk assessment, remediation, or tourist management of abandoned mining sites. The recent results are applicable to other types of abandoned mines in the world. However, we should expect new findings and investigation of as yet undescribed geomorphic forms.

Bioactive compounds recovery by freeze concentration process from winemaking by-product

Grape pomace is the main solid residue of wine industry, containing high amounts of phenolic compounds. Considering its high potential, an extraction procedure was optimized for maximal recovery of anthocyanins from grape pomace (Vitis vinifera L.) using citric acid as a generally recognized as safe (GRAS) acidulant in water. Volume of solvent (3.2-36.8mL), time (14.4-165.6min) and pH of solvent (1.12-4.48) were the studied variables. Furthermore, the best condition to obtain extract rich in anthocyanins was submitted to the gravitational block freeze concentration process. The performance of the process was evaluated and cryoconcentrated and ice fractions were analyzed for physicochemical properties, bioactive compounds content, and antioxidant activity. Interaction, linear, and quadratic effects for volume and pH of solvent were significant by analysis of variance (ANOVA). The experimental design allowed the prediction for maximal recovery of anthocyanins (10mL of solvent at pH 1.8). The bioactive composition of the optimized grape pomace extract was influenced by the cryoconcentration process. After three cycles using gravitational block freeze concentration, the total phenolics and monomeric anthocyanins were approximately 4 and 5 times higher than the initial condition of the extract, respectively. Consequently, an increase in antioxidant activity was observed. The increase in the concentration of bioactive compounds reached a process efficiency of 93% (stage 1) for phenolic compounds and 91% (stage 2) for anthocyanins. Therefore, the final water-based optimized method is safe and has a low cost and the concentrated extract certainly showed higher concentrations of total phenolics and anthocyanins, compared to the initial extract. The proposed clean extraction method and cryoconcentration technique can be considered important strategies for recovering and valuing grape pomace components, improving the approach to the circular economy concept in the wine industry.

Comparison of two 2-D numerical models for snow avalanche simulation

Snow avalanches are gravitational processes characterised by the rapid movement of a snow mass, threatening inhabitants and damaging infrastructure in mountain areas. Such phenomena are complex events, and for this reason, different numerical models have been developed to reproduce their dynamics over a given topography. In this study, we focus on the two-dimensional numerical simulation tools RAMMS::AVALANCHE and FLO-2D, aiming to compare their performance in predicting the deposition area of snow avalanches. We also aim to assess the employment of the FLO-2D simulation model, normally used in water flood or mud/debris flow simulations, in predicting the motion of snow avalanches. For this purpose, two well-documented avalanche events that occurred in the Province of Bolzano (IT) were analyzed (Knollgraben, Pichler Erschbaum avalanches). The deposition area of each case study was simulated with both models through back-analysis processes. The simulation results were evaluated primarily by comparing the simulated deposition area with the observed one through statistical indices. Subsequently, the maximum flow depth, velocity and deposition depth were also compared between the simulation results. The results showed that RAMMS::AVALANCHE generally reproduced the observed deposits better compared to FLO-2D simulation. FLO-2D provided suitable results for wet and dry snow avalanches after a meticulous calibration of the rheological parameters, since they are not those typically considered in avalanche rheology studies. The results showed that FLO-2D can be used to study the propagation of snow avalanches and could also be adopted by practitioners to define hazard areas, expanding its field of application.