Slope Zone Research Articles

Nearshore Wave Propagation Characteristics in Steep Slope Zone of South Java Sea

NCEP provided the ocean wave long term data, one year nearshore wave surveyed at -20m water depth of South Java coast, the relation between two series synchronous data were analyzed, the wave direction are all prevailing from S to SSW. The wave in India Ocean is mostly swell, the significant wave height and period changed obviously and disorder while it is propagating on steep slope from deep water to shallow water. The wave spectrum were calculated, H0 and Tp were adopted for analyzing wave propagation characteristics from global wave position to survey position. The survey wave H0 and Tp have good relation with global wave. The reason of statistic Hs and Ts decreasing is dispersion on shallow water, which is shown from water surface elevation process.

Metamorphism of the Dizi Series Rocks (the Greater Caucasus): Petrography, Mineralogy and Evolution of Metamorphic Assemblages

The Dizi Series is exposed within the Southern Slope zone of the Greater Caucasus, in the core of the Svaneti anticlinorium. It is mainly composed of terrigenous, volcanogenic and carbonate rocks faunistically dated from the Devonian to the Triassic inclusive. Regional and contact metamorphism of the Dizi Series rocks was studied. It is stated that the degree of regional metamorphism corresponds to the chlorite-sericite subfacies of the greenschist facies, occurring at a temperature of 300–350°C and a pressure of 1.5–2.3 kbar. As a result of the action of the Middle Jurassic intrusive rock bodies, the regionally metamorphosed rocks of the Dizi Series underwent contact metamorphism. Three zones of contact metamorphism were distinguished corresponding to albite-epidote-hornfels, andalusite-biotite-muscovite-chlorite-hornfels and andalusite-biotite-muscovite-hornfels subfacies. Contact metamorphism took place at a significantly higher temperature and lower pressure than the preceding regional metamorphism. The maximum temperature of the contact metamorphism reached ≈ 570°С, while pressure varied within the range of ≈ 0.3–0.8 kbar. The evolution of rock associations of regional and contact metamorphism of the Dizi Series was studied. The fields of facies and subfacies of regional and contact metamorphism are shown in the Ps-T diagram. Three age populations of zircons were identified using U-Pb LA-ICP-MS dating of the diorite-porphyrite intrusion in the Dizi Series: Zrn1 (ca. 2200 Ma) and Zrn2 (458 ± 29 Ma) that were captured by the diorite-porphyrite magma from the ancient magmatic and metamorphic rocks of the crystalline basement, and Zrn3 (166.5 ± 4.6 Ma) that corresponds to the age of diorite-porphyrite crystallization.

五墩凹陷北部斜坡带储层沉积特征及油气勘探意义

五墩凹陷北部斜坡带储层沉积特征及油气勘探意义

BLACK SEA SUBMARINE VALLEYS – PATTERNS, SYSTEMS, NETWORKS

The article presents a detailed analysis of the underwater morphology of the entire Black Sea basin beyond the shelf break. The focus is on submarine valley systems on continental slope and rise zones, and partially in the abyssal plain area. The present research is among the very few studies that have undertaken a morphological analysis on a regional scale, for an entire marine basin. This achievement was possible by using the publicly available EMODnet bathymetric map of the Black Sea. The Black Sea submarine valleys networks are presented in a map-sketch. It includes 25 valley systems, 5 groups of simple first order channels, and other number of simple, not associated channels. The 25 valley systems are adding up more than 110 main channels and tributaries. Morphological description and analysis of each of the mapped systems is given – shape and plan view morphology, dimensions (length and surface) and slope gradient. Some considerations about the amount of sediments supplied by the valleys from the shelf to the basin floor, forming the deep-sea fans, are presented. For a more detailed and precise image of the Black Sea network of submarine valleys additional work would be necessary to cover the entire basin with a minimum standard network of modern bathymetric mapping and of high resolution seismic survey lines. To take into account the composition and geological structure of different sectors, as factors that influence significantly the morphology of the seabed, would be also particularly useful.

Adaptive neural asymptotic control for uncertain nonlinear multiagent systems with a fuzzy dead zone constraint

A consensus control scheme is developed for a class of leader-follower multiagent systems with a fuzzy dead zone constraint. Differently from previous work, the method developed implements a predefined convergence of tracking errors for multiagent systems; especially, the dynamic model for each follower has a fuzzy dead zone input. To solve the problem, not only a set of smooth functions are used within the control design to increase the stability of the systems but also the unfuzziness and center-of-gravity method are used to analyze and process the actuator constraint model, where each slope of the dead zone is uncertain and fuzzy. It is verified that the method developed effectively guarantees that the tracking errors of multiagent systems can converge to a predefined interval; that is, the problem of better asymptotic consensus performance for nonlinear multiagent systems is solved. Simulation illustrates the results obtained.

Investigating the effect of carbon interfacial layer on the elastoplastic response of ceramic particle-reinforced metal matrix composites

Titanium-based composites with their desirable and great mechanical properties are in high demand. One of the main problems that arise in this field is the chemical reactions that appear between strengthening the material and the matrix that usually undermines the integrity of the composite. This problem will result in dangerous defects such as debonding or degradation of the properties. In this work, a coating solution is presented; a similar process as discussed in the literature yet analytically different. The coating is commonly used for protecting and preserving the reinforcing material’s surface which is in contact with the matrix. Herein, a titanium metal matrix composite reinforced with carbon-coated SiC particles is discussed. Mori-Tanaka method was utilized to firstly determine the properties of the inclusion which is the carbon-coated SiC particle and then using the results based on the thickness of the coating and volume fraction of inclusions, calculating the overall properties of the composite. An incremental method was employed to then calculate the stress-strain curve of the said material. The results obtained were in good agreement with the experimental data. The negative effect of the carbon coating on the elastic properties of the SiC/titanium composite was observed as the coating layer thickness increased. The same thing was observed in the stress-strain curve in the slope of the elastic zone and work hardening growth in the plastic zone.

Optimization of a storm drainage network using the storm water management model software in different scenarios

The research developed was based on the design and optimization of a storm drainage network, with the objective of finding solutions to possible flooding events. For this purpose, three study areas of different topographic conditions were defined in the city of San Jose de Cucuta, Colombia, with an extension of 16.82 ha (high slope zone), 12.85 ha (medium slope zone) and 12. 10 ha (low slope zone); subsequently, a storm drainage network was designed for each of the study areas based on the current specifications of Colombian standards; the storm drainage network was modeled using the storm water management model software of the Environmental Protection Agency of the United States of America, a cost-benefit comparison was developed for the two alternatives. At the conclusion of the investigation, it was found that by elaborating the cost structure for the different conditions from both the initial and optimized designs, a savings of 17.8% was obtained in the high slope, 22.4% in the medium slope and 24.6% in the low slope, mainly in activities such as excavation and pipe diameters.

Composition of low molecular weight impurities in dimethylmethylpheylsiloxane rubbers with terminal hydroxyl groups

Synthesis of dimethylmethylphenylsiloxane rubbers with terminal hydroxyl groups by copolymerization of cyclosiloxanes can be accompanied by formation of low molecular weight compounds, impurities, which are difficultly removed (due to target product affinity) and can lead to rubber opalescence. Identification of the impurities (the content of each impurity ≥ 10 –4 wt.% in 1 μ l of the sample) can be carried out using a sensitive gas chromatography-mass spectrometric method. The method allows separation of the analyzed mixture into individual components on a capillary column. These components enter a mass analyzer and undergo electron ionization which leads to their dissociation into pairs «cation – neutral fragment». Only positively charged ions are observed in the mass spectra, which provides the possibility of predicting the structure of the analyzed siloxane impurities. Rearrangement of linear and cyclic molecules occurring upon mass spectrometric fragmentation result in their transformation into cyclic and bicyclic cations. The structure of the cations formed under ionization conditions depends on the number of silanol bonds and their location in the molecule. To prove the presence of compounds with hydroxyl groups in the composition of impurities and to demonstrate the effect of electron ionization on the fragmentation of compounds with silanol bonds, a sample of oligomethylsiloxane with terminal trimethylsiloxy groups was synthesized in a similar way using the copolymerization method. Compounds with silanol bonds present in the composition of the impurities appear as chromatographic asymmetric peaks with ascending and descending gently sloping zones. Those compounds are rearranged either when passing through a chromatographic column due to sorption-desorption and enter the detector in a modified form or drift through the column and undergo rearrangements already under conditions of electron ionization. The impurities contained linear and cyclic methylsiloxanes with silanol and phenyl bonds. The chromato-mass spectrometric method provide a reliable control of the composition and content of undesirable impurities which cause rubber opalescence.

Applying Automatic Mapping Processing By GMT to Bathymetric and Geophysical Data: Cascadia Subduction Zone, Pacific Ocean

AbstractThe Cascadia Trench is stretching along the convergent plate boundaries of Pacific Plate, North America Plate and Juan De Fuca Plate. It is an important geomorphological structural feature in the north-east Pacific Ocean. The aim of the paper is to analyse the geomorphology of the Cascadia Trench west of Vancouver Island (Canada and USA) using the GMT cartographic scripting toolset. The unique geomorphological feature of the Cascadia Trench is that the thick sediment layer completely obscures the subduction zone and abyssal hills. This results in the asymmetric profile in the cross-section of the trench. Bathymetric data were extracted from the GEBCO 2019 dataset (15 arc-second grid), sediment thickness by the GlobSed dataset. Due to the dominance of high sedimentary rate and complexity of the tectonic processes and geologic settings, Cascadia Trench develops very specific asymmetric geomorphic shape comparing to the typical V-form. The results of the geomorphic modelling show that eastern side of the trench has a gentle curvature (slope: 35.12°), partially stepped, due to the tectonic movements and faults. The opposite, oceanward side is almost completely leveled. The trench is narrow with maximal depth at the selected segment -3489 m and for the whole dataset -6201 m. The most repetitive depth is in a range -2500 to -2400 m (267 samples) and -2500 to -2600 m (261 samples). The bottom is mostly flat due to the high sedimentation rates indicating the accumulative leveling processes. Marine free-air gravity anomalies along the Cascadia Subduction Zone are characterized by weakly positive values (20 mGal) increasing rapidly in the zone of the continental slope (>200 mGal), which is associated with a decrease in thickness of the Earth’s crust.

Geochemistry of light petroleum from the North of Dongying Depression

With ever-increasing exploration for oils, exploration has inevitably extended into deep layers. Considerable quantity of light oil is discovered from deep Es4 lower layer in the northern steep slope zone of Dongying Depression, Bohai Bay Basin. The oils are characterized by high content of saturated hydrocarbon and low concentration of biomarker and sulphur content. Eleven oil samples and forty-five source rock samples are finely analysed. According to the results of monomer hydrocarbon isotope analysis, carbon and oxygen isotope composition analysis and light hydrocarbon analysis, it is confirmed that the oils in deep strata of northern steep slope zone reach high mature lever. The light oils in the northern steep slope zone have a relationship with deep Es4 lower hydrocarbon source rocks by the results of monomer hydrocarbon isotope and light hydrocarbon analysis. Thermal evolution studies show the top Es4 lower hydrocarbon source rocks have a high thermal evolution level. The top Es4 lower hydrocarbon source rocks have relatively high organic abundance and are dominated by types I-II1 kerogen. This research is helpful for unravelling deep petroleum resources evaluation in this area. The viewpoint will be of great significance in future exploration. Moreover, the views in this paper can also be applied to other basins to explore for deep oil reservoirs.

Assessment of Soil Erosion Using the RUSLE Model for the Epworth District of the Harare Metropolitan Province, Zimbabwe

Urban development without adequate soil erosion control measures is becoming a major environmental concern in developing urban areas across Africa. These environmental disturbances encompass rampart Land Use and Land Cover changes (LULC) due to a high population growth rate and increased economic activities. To understand the influence of accelerated LULC changes and urban expansion as major drivers in landscape degradation in the Epworth district of the Harare Metropolitan Province, the RUSLE model was employed. This considers land use, soil, climate and topography as input parameters in the assessment of the extent and impact of these drivers on soil erosion. The Revised Universal Soil Loss Equation (RUSLE) was used to predict the potential erosion between 1984 and 2018 and soil erosion risk for the years 2000 and 2018. The mean rate of the predicted potential soil erosion was 13.2 t ha−1 yr−1 (1984–2018); areas especially vulnerable to erosion were predicted for foot slope areas with direct tributaries to the major streams and steep sloping zones. The average soil erosion risk was estimated at 1.31 t ha−1 yr−1 for the year 2000 and 1.12 t ha−1 yr−1 for 2018. While the overall potential soil loss decreased between 2000 and 2018, the potential soil loss was observed to increase tremendously in residential areas, which doubled in extent between 2000 and 2018. The findings reveal that about 40% of the Epworth district was threatened by unsustainable soil loss resulting from increased soil erosion risk within the built-up areas.

A comparative study of soil processes in depletion and accumulation zones of permafrost landslides in Siberia

Landslides are one of the main reasons for permafrost degradation in high latitudes. Any landslides consist of different top-down slope zones: removal, transit-depletion, and accumulation zones. These slope parts can demonstrate different successional behavior of plant community and carbon (C) cycling during post-sliding seral stages. To address this issue, soil respiration (SR), hydrothermal conditions (mineral soil temperature at a depth of 5 cm (ST5, °C), and gravimetric soil water content at a depth of 0–5 cm in mineral soil horizon (SWC5, %)), total soil C (TC) and nitrogen (TN) contents, and soil microbial activity at the middle (depletion zone) and lower (accumulation zone) slope parts of the landslides with different history have been studied. The most significant differences between the middle and lower slope positions were found at the ground microsites (or G-plots) of the L2001 landslide. Thus, here, a midslope part occurred to be a high source of C compared to the lower part. Midslope of L2001 was characterized by significantly higher SR at G-plots as well because of better hydrothermal conditions and more intensive vegetation regeneration. The accumulation zone of L2001 characterized by the lower SR despite significantly higher microbial activity due to the high nutrient level of the soil moved from the top, likely favored to promotion of the soil C stabilization processes. Despite the registered ST5 differences in the E-plots and the G-plots between middle and lower slope positions of the L1972 landslide, SR, TC, TN, and soil microbial activity did not differ significantly.

Geological characteristics and shale oil potential of the lacustrine immature to low mature shale oil system: a case study of the second member of Kongdian Formation in Cangdong Sag, Huanghua Depression, Bohai Bay Basin, China

ABSTRACT The Second Member of Kongdian Formation (Ek2) shale oil system is a set of thick organic-rich lacustrine shales with great shale oil resources potential. The shales are oil-prone with high organic matter abundance (samples with TOC > 2% accounting for 72.6%) and low maturity (the Ro of samples between 0.42% and 0.84%). The Ek2 shale system is dominated by shales, sandstones, and carbonate rocks, which can be subdivided into various-mixed lithologies. The shales are primarily composed of clay minerals, quartz, feldspar, calcite, dolomite, pyrite, siderite, and zeolite, with no obvious predominant minerals. The brittle mineral content is high with an average content of 73.86%, which is conducive to reservoir stimulation. Physical properties and oil saturations vary significantly among different lithologies. Tight sandstones (average porosity 8.66%, average permeability 2.207 × 10−3 μm2) and dolomites (average porosity 5.26%, average permeability 1.910 × 10−3 μm2) have better exploration potential than shales (average porosity 2.46%, average permeability 0.937 × 10−3 μm2). Considering Ro distribution, the slope zones are more favorable than Kongdian Structure Belt laterally and the lower intervals of the Ek2 shale are more potential for shale oil accumulation than the upper interval vertically.

Origin of crude oils from the paleogene Xingouzui formation in the Jiangling depression of Jianghan basin, central China

The Paleogene Xingouzui Formation is one of the exploration targets in the Jiangling Depression from Jianghan Basin, Central China. However, the origin and source of crude oils remains controversial. In the present work, a total of 16 fresh source rocks and 23 oil samples were collected and geochemically investigated to clarify the source of organic matters, sedimentary environment and evolution degree. The Xingouzui Formation source rock samples are mainly of fair−good source rocks, with the TOC content, S1 and S2 of 0.36%–1.36% (mean of 0.74%), 0.14–0.38 (mean of 0.27 mg HC/g rock) and (mean of 1.12 mg HC/g rock), respectively. And these rocks are dominated by type Ⅱ2 kerogen within “oil window” maturity stage, with the Ro value of 0.6%–1.2% (mean of 0.9%). The biomarker results indicate that the source rocks of the Xingouzui Formation are mainly deposited in anoxic reducing environment, which main source materials are the mixture of terrestrial higher plants and lower marine organisms. The Pr/Ph values of the oils and source rocks range of 0.47–0.64 and 0.23–1.07, respectively. And the δ13C values of the oils and source rocks range from −34.93‰ to −26.41‰ and from −28.3‰ to −23.8‰, respectively. Family-I and family-Ⅱ oils were separated based on the results of biomarkers and stable carbon isotope, indicating that family-I oils, mainly occurring in the Wancheng fault zone and Gonggan slope zone, are characterized by relatively lower homohopane series, higher mature, and less input of terrestrial higher plants. Comparatively, family-Ⅱ oils mainly occur in the Jingzhou anticlinal zone, with the characterization of small amount of homohopane series, less mature and more terrigenous organic matter input. Family-I oils mainly originate from of the Ⅲ and Ⅱ groups of the lower Xingouzui Formation (Ex1-Ⅲ and Ex1-Ⅱ) source rocks in the Wancheng fault zone and less contribution from Ex1-Ⅱ source rocks of the Shiqiao monoclinal zone; while family-Ⅱ oils are mainly derived from the Ex1-Ⅲ source rocks in the north of Jingzhou anticlinal, and a small amount comes from the Ex1-Ⅱ source rocks of the Shiqiao monoclinal zone. In addition, Ex1-Ⅱ and Ex1-Ⅲ source rocks in the Wancheng fault zone show some contribution to family-Ⅱ2 oils. This work could provide scientific theoretical guidance for petroleum exploration and exploitation in the Jiangling depression.

ЭРОЗИЯ ПОЧВЫ ВОДОЙ И МЕРЫ БОРЬБЫ С НЕЙ

The factors causing water erosion have been investigated, an influence of erosion on soil fertility, agrophysical and agrochemical features, complications and economic losses, and also measures against erosion have been offered in this article. It was known that the last results of the erosion process was vividly shown in plants productivity. So, in areas where erosion is developing the plants productivity is 2-5 times lower in comparison with the areas where erosion isnꞌt observed and areas which are cultivated with the high agrotechnical rules. Thus, the agriculture suffers damage. During the research the raindrops and irrigation erosion were widely investigated. It was determined that as a result of the raindrops erosion the soil structure is obliterated, porosity decreases, penetration of water and air into the soil becomes difficult. To prevent from raindrops erosion it is recommended to determine rainfall quantity and intensity on seasons and to provide coverage of soil with the plant. It was determined that the zone slope, granulometric and structural composition, coverage percentage, not following the irrigation norms and rules caused formation and development of irrigation erosion. The research results show that while an amount of the muddy flow is 51,40 g/l in one liter of the flood water, this quantity is 43,50 g/l in the area, where the water consumption is 2,5 l/sec., it is 30,10 g/sec. in 2 l/sec. of water consumption.

Optimal Design of a High Slope for Ice World & Water Park (IWWP) Built Over an Abandoned Quarry: A Case Study in Changsha of China

The Ice World & Water Park (IWWP) is a huge recreational building that stands on the Dawangshan Pit which is an abandoned limestone quarry in Changsha, China. The effective reinforcement of slope is imperative to ensure the slope stability and the safe operations of IWWP project. In this paper, we present a numerical and field testing study on the optimal design of slope in Zone C. First, a comprehensive comparison and analysis of three different types of retaining structures (anchored sheet pile wall, cantilever and anchored double sheet pile walls) behavior under excavation and earthquake conditions are performed using a finite element model. In the meantime, the uncertainty in strength and deformation parameters are considered in the numerical calculations. On this basis, the parametric study was conducted via varying the row distance, pile diameter, pile spacing, coupling beam section and the number of anchor cables to obtain the optimum design parameters of the anchored double sheet pile wall structures. The numerical results and measured data show that the supporting structures were in a safe working state. The pile spacing, pile diameter, the number of anchor cables are the primary factors influencing the performance of the retaining system, and can be regarded as several critical parameters for the optimal design of the anchored double sheet pile wall structures. While the row distance and coupling beam section have insignificant effect on the retaining structures behavior. The conclusions of this paper will help professional when designing the anchored double sheet pile walls system of similar projects.

Does land use type impact the demographic and spatial structures of Adansonia digitata L. in the Pendjari Biosphere Reserve in Northern Benin?

Changes in land use type (LUT) are a major driver of biodiversity loss and species decline. Responses to changes in LUT are species-specific, which may in turn be context-dependent. Understanding such responses is essential for the management of socio-economically important wild tree species. The baobab, Adansonia digitata L., is an important traditional agroforestry tree species in Sub-Saharan Africa. This study assesses how LUT affects the demographic and spatial structure of baobab stands. Using data from a census and mapping of baobab trees in 12 plots of 250 m × 250 m each, the study compared baobab tree density, total height and diameter, diameter size-class distribution (SCD), stand stability, and spatial relationships in a strictly protected area (national park), a buffer zone and farmlands (Matéri and Boukombé) in the Pendjari Biosphere Reserve in Benin. The results show that the highest young and adult tree densities are in farmlands (particularly in Matéri), followed by the buffer zone and the national park. No significant differences in tree diameter and total height of baobab trees were found among the different LUT. The SCD had a reverse J-shape with a better negative slope and population stability metrics in farmlands (particularly in Matéri) but a flattened slope in the buffer zone. The spatial distributions of juvenile and adult baobab trees were random, and independent of each other. The spatial distribution of juvenile and adult baobabs was also independent of the other tree species, irrespective of LUT. It was concluded that baobab conservation is better in farmlands than in the national park but that the difference between park and farmlands may be context-dependent, probably linked to local environmental conditions, the socio-ecological context and interactions with baobab trees.

An indicator based approach for assessing the vulnerability of riparian ecosystem under the influence of urbanization in the Indian Himalayan city, Dehradun

Riparian ecosystems are critical biological habitat that needs to be preserved. These systems face multiple stresses of altered water regime, increased human interference and biological invasion, climate change, land developments and other site-specific issues that may include eutrophication and urbanisation. In due course of urbanisation, riparian vegetation is replaced by both impervious and less permeable surfaces causing more frequent floods, greater total surface runoff, and decreased time to produce runoff. This may result in flooding of the city when a substantial rain is received. In this study, we evaluated the vulnerability of riparian zones in Dehradun city of India due to urbanisation using a series of indicators extracted from remote sensing data. The changes in the landscape pattern of the riparian zones were examined by analyzing and manipulating Landsat-8 and Sentinel-2 datasets using Google Earth Engine, ArcGIS 10.1 and ERDAS IMAGINE 2014 software. Factors influencing the changes within the riparian area were identified using higher resolution image, existing base maps and reconnaissance surveys to qualify them as one of the indicators. Anthropogenic activities such as new residential buildings, infrastructure (such as roads), farming activities and commercial activities (industrial set up) were some of the factors contributing to the vulnerability of riparian zones. The final indicators in the form of riparian zone slope, extent of the riparian area, vegetation cover, human disturbance were mapped as raster layers and were integrated in a GIS environment to obtain final vulnerability map. This was intersected with settlement density map to categorize the vulnerability levels for three settlement density classes of low, medium and high. The findings reveal a significant land cover change within the riparian zones over a period of twenty years (2000 to 2019) with various levels of human encroachment. It was observed that 26.15% of the riparian area falls under low, 47.68% under medium, 12.98% under high, and 13.19% under very high vulnerability classes. Furthermore, the coverage percentage of high vulnerability class was largest in the low and high settlement density areas of riparian zones accounting for 36.96% and 51.48%, respectively. The majority of the area (74.36%) falls under medium vulnerability class under medium settlement density class. The study provides an opportunity to map riparian zone vulnerability considering predominant indicators of vulnerability that could be mapped using remotely sensed data and application of GIS tools.

Slope stability analysis of man-made soil body surrounding the abandoned hydraulic dump

Introduction. Pit slope sections directly adjoining hydraulic dumps are characterized by the higher risk of landslide, especially in case of storing dry overburden rock over the hydraulically filled overburden. It is contributed to by the combination of the following factors: increase of the total height of the slope, development within the slope of a waterlogged zone of weakness with complex footprint map and depth configuration; excessive pore pressure within this zone which grows by means of adding dry dump to hydraulically filled rock. To reduce risks connected with man-made soil body slope stability violation, slope stability analysis is carried out based on the results of geological survey, hydrogeological observations and geophysical sounding. Research aims to analyze the stability of the Krasnobrodsky coal pit man-made mass adjoining the Bakhtykhtinsky hydraulic dump based on the 3D geological-geophysical model. Methodology. The authors of the article offered and realized the algorithm of analyzing the stability of slopes based on 3D geological and geophysical models formed by integrating geological, hydrogeological and geophysical data. Results. Based on geological survey data analysis, hydrogeological survey and electric sounding, 3D geological-geophysical model of a man-made soil body adjoining Bakhtykhtinsky hydraulic dump has been built. Slope stability analysis of an actual state of the man-made soil body has been carried out. ISSN 0536-1028 «Известия вузов. Горный журнал», № 5, 2020 55 Summary. In order to develop a 3D geological-geophysical model, in addition to slope geometry, it is necessary to set the boundaries of waterlogged rock in a footprint map and in depth, and monitor pore pressure within this zone. To determine slope section with minimum safety factor it is necessary to carry out cyclic calculation with gradual reduction of approach and design section rotation increment.

Sandbar dynamics in microtidal environments: Migration patterns in unprotected and bounded beaches

Novel observations of bar features and migration patterns at three Italian sandy beaches in Senigallia (central Adriatic Sea) and Terracina (central Tyrrhenian Sea) are presented. While two of these beaches are unprotected, one is artificially embayed through the presence of a concrete jetty. Bar locations and motions are analysed with video imagery data sets from coastal monitoring stations. Wave climate from the Copernicus oceanographic model is used to correlate hydrodynamics and beach morphology. Clear net offshore migration (NOM) patterns are identified at all beaches, although exhibiting different response scales. At the low-slope beach of Senigallia (mean surf zone slope of 0.009) bars are more sensitive to seasonal changes in wave climate, with offshore shifts in winter and inactivity in summer. Mean annual migration rates of up to 0.26 m/day and 0.09 m/day are observed for outer and inner bars, respectively. No significant response to single storms is observed, except during a single NNE storm. No distinct erosive or accretive trend for the shoreline is evidenced. At the steep beach of Terracina (mean surf zone slope of 0.018), conversely, bars are strongly responsive to single storm events, with displacements of up to 25–50 m across a single storm. The mean inter-annual migration rate is 0.08 m/day for the single/outer bar, whereas a slight onshore trend (-0.02 m/day) for the newborn inner bar is established. The presence of an artificial jetty at the Misa river mouth in Senigallia, finally, leaves the bar system, typically oscillating around an equilibrium position, susceptible to larger seasonal oscillations and strong offshore migration due to two ESE storm events. Numerical simulations of nearshore circulation for two storms from different directions predict the birth of longshore currents, higher ratios of significant wave height to water depth, and stronger bottom orbital velocities over bars in case of the ESE storm, suggesting a greater tendency for offshore-directed sediment transport.