Average Slope Angle Research Articles

Frontal Bone Morphology in Different Age and Gender Groups Using Computed Tomography.

The shape of the forehead is primarily determined by the frontal bone, which holds significance for health and aesthetics. This study evaluated the morphology of the frontal bone in different age groups and genders using computed tomography (CT). This cross-sectional study was conducted on CT scan results of 220 patients divided into three age groups: 20-29.27, 29.27-47.54, and 47.54-95 years. The investigation explored the lower and upper angles compared with the Sella-Nasion (SN) line, the maximum frontal projection with Nasion in the SN plan, and the variations in frontal thickness across different angles (15, 30, 45, 60, 75, and 90 degrees) relative to the SN plane. All data were analyzed using R software, considering the significance level p < 0.05. Of 220 patients, 119 were men, and the mean age of the participants was 41.09 ± 18.06 years. The average upper frontal slope (UFS) angle was 56.96 ± 8.17 degrees, which was 59.35 ± 7.92 degrees in females and 54.94 ± 7.86 degrees in males. The mean lower frontal slope (LFS) angle was 86.30 ± 7.96 degrees, which was 90.71 ± 6.67 degrees in females and 82.55 ± 7.00 degrees in males. The average contour nasion (C-N) distance was 7.51 ± 3.72 mm. Also, the frontal thickness at an angle of 15 degrees had the highest value of 13.08 ± 2.68 mm and at 30 degrees had the lowest value of 5.81 ± 1.56 mm. A significant difference was observed between the UFS and LFS among males and females (p < 0.001). Across all age groups, men exhibited a steeper angle, indicating a greater posterior inclination than women. Moreover, males with upper ages reported a significant increase in C-N distance and frontal projection (p < 0.05). Our findings emphasize the importance of considering gender-specific variations in frontal bone structure when planning cosmetic or reconstructive procedures involving the forehead.

Exploiting the land use to predict shallow landslide susceptibility: A probabilistic implementation of LAPSUS-LS

Due to the significant role of land use on the occurrence of rainfall-induced shallow landslides, this factor is commonly employed as a landslide susceptibility predictor. However, the land use classification is oftentimes very broad, neglecting the proven mechanical and hydrogeological role of the land management on slope stability. Given the necessity of including spatially distributed and management-specific inputs, the process-based landscape evolution model LAPSUS-LS was chosen and adapted to achieve a probabilistic approach which takes into account land management as an input by adopting management-specific values of root cohesion. The model was applied to four test sites in the Oltrepò Pavese (Italy), where different vineyard management techniques play a significant role in triggering landslides. The results for the four test areas had, cumulatively, an Area Under the Roc curve greater than 0.73, with false negative cells being < 1 % of the total for all simulations. In the model’s application, land use practices characterised by higher root cohesion proved to benefit slope stability, whereas tilled vineyards, shrublands and abandoned vineyards were more prone to the formation of shallow landslides. In addition, we found that the inclusion of management-specific input parameters produced more accurate outputs and that in catchments characterised by average slope angles lower than 15°, varying the vineyard management, did not appear to affect the landslide susceptibility. Due to the model’s high dependency on the land use and its ability to include land management, it can take into account the spatial variability of input values such as the root cohesion. Additionally, it can be applied i) to manage current conditions, ii) to explore future land use change, iii) to study less invasive yet beneficial land use management change scenarios and iv) provide farmers of at-risk areas insight on how to improve slope stability.

Influence of tidal asymmetry on local scour near the offshore platform

An in-situ mooring measurement was conducted using a profiling sound of navigation and ranging (SONAR) system to reveal the influence of tidal asymmetry on the local scour near an artificial offshore platform, Southwest Offshore Windfarm Complex, Korea. During the mooring period, the flood tide was significantly dominated by positive tidal duration asymmetry and skewness. The lengths of scour hole were 9.8m and 5.1m along the flood and ebb directions, respectively. Flood-dominated currents intensified the horseshoe vortex, resulting in an approximately 10% deeper scour hole on the flood face than the ebb face. The periodic occurrence of bidirectional currents generated vortices that facilitated the mixing and redistribution of seabed sediments, forming a gentle slope within the scour hole. The average slope angles ranged from 14° to 16° on the flood face and 6° to 8° on the ebb face. Despite the strong influence of local scour, variations in scour depth (Ds) consistently remained around −2.15m, suggesting the exposure of the underlying consolidated sediment layer. During the intermediate period from spring to neap tide, the Ds on the lower slope of scour hole increased by 0.12m, while it decreased by 0.11m from neap to spring tide, suggesting that the net Ds gradually approached zero over the tidal cycle. These findings underscore the importance of understanding tidal impacts on the local scour morphology to enhance the stability and design of offshore wind turbine foundations.

Collapse caldera walls: Mechanical controls on slope failure and morphology

Volcanic calderas are enclosed topographic depressions that are commonly delimited by steep annular cliffs (caldera walls). The walls represent degraded scarps of ring faults that accommodated caldera collapse. Here, we assess the mechanical controls on caldera wall morphology and failure by: (i) analysing slope properties of recently formed calderas; (ii) examining analytical solutions for slope failure; and (iii) simulating progressive slope failure via Distinct Element Method (DEM) numerical modelling. Average slope angles of the caldera walls in nature range from 20° to 65° and slope heights range from 99 m to 1080 m. Smaller slope heights are weakly tied to greater slope inclinations. Almost 60% of sampled caldera wall profiles show a steeper upper section and a gentler lower section, which in numerical models are reproduced as an upper slope comprising intact wall rock and a lower slope comprising failed material inclined at the angle of repose. Moreover, modelled material with a low angle of internal friction and low cohesion exhibits shear failure, whereas material with high friction and high cohesion shows tension cracking, buckling and toppling. The slope height and inclination data from the numerical models agree well with those in nature. The numerical model data correspond more closely to analytically-predicted failure planes than critical (i.e. limit equilibrium) slopes because they are short-lived and therefore unlikely to be sampled in either model or nature. If rock mass cohesions or friction angles constrained analytically from natural slopes are determined by assuming the slope is critical, they are likely to be underestimates. The homogeneous numerical models here give an estimated natural rock mass cohesion of 0.5 MPa or less. This is much lower than typical laboratory-scale cohesion values, and it highlights the importance of strength reduction when upscaling mechanical parameters from laboratory experiments for modelling slope stability and volcano deformation.

Geomorphological significance of the morphometric characteristics of first-order basins in the Siwalik Hills in the Himalayas, Nepal

ABSTRACT First-order basin morphology is important for the functioning of the whole hydrologic system. This study examines the geomorphology of three areas in the tectonically active Siwalik Hills, Nepal, using morphometric variables. Twenty variables for 11,200 first-order basins were obtained from maps and Digital Elevation Models (DEMs) of three areas (the Machheli, Banganga and Binai river basins). Principal component analysis of each area condensed these into 6 major components, which accounted for 78–82% of the total variance in each data set. Rotated principal components were remarkably consistent between the three areas. The average slope, area, elevation range, valley angle, shape index, hypsometric integral, basin asymmetry factor and drainage density were identified as the eight most important morphometric variables defining these components. Ordinal grouping and k-means clustering led to recognition of eight basin types, distinguished predominantly by elevation range, average slope, area and valley angle. Shallow and steep basins are predominant in all three areas. The spatial distribution of first-order basin types exhibits a distinct pattern of geomorphic regions. The study demonstrated that a first-order basin is a suitable unit to demonstrate the morphological characteristics of a geologically complex area, and the study approach can be applied more broadly.

Perancangan Alat Penentuan Koefisien Gesek Statis Menggunakan Sensor IR FC-51 dan Potensiometer Berbasis Arduino Uno

An Arduino Uno-based static friction coefficient (µs) determination tool equipped with an IR sensor module FC-51 has been created. This µs determination tool is made to reduce the possibility of observation errors when doing physics labs. The µs determination tool consists of an FC-51 IR sensor component to detect precisely when an object is moving. The potentiometer measures the angle of the base surface, and an Arduino Uno device transmits data from the hardware to the computer in real time. The work test of the µs determination tool starts with the base surface with a slope of 0o, and then the object is placed on the base surface and precisely above the surface of the FC-51 IR sensor. When the base surface is tilted slowly, the potentiometer also rotates, showing the plane angle's size. As long as the object is not moving, the IR FC-51 sensor is in low condition. When the object moves, the IR FC-51 sensor is in high condition. The change in signal from low to high indicates that the object is moving when the plane reaches the slope angle, and the slope angle shows the value of µs. The µs are measured on a wooden base with wooden blocks and a glass base with glass blocks. The results obtained for a wooden base with wooden blocks µs = 0.73 with an average slope angle = 36.16o and a glass base with glass blocks µs = 0.4 with an average slope angle = 22.1o. The results show that the µs level of the wood surface with wood is greater than the µs level of the glass surface with glass.

Compilation of Parameter Control for Mapping the Potential Landslide Areas

Batu Tourism City is located in a mountainous area, so based on information from the BNPB, it has quite a large potential for landslides. Landslide hazards can frequently disrupt public traffic due to road cuts. Landslide mapping digitally will contribute to handling and mitigation activities since the database can be updated in real time to anticipate landslide hazards. This study aims to map landslide-prone areas located in the Payung zone, Songgokerto Village, and Batu City. Landslide areas can be determined by mapping analysis using GIS software. GIS can determine the classification level for a landslide susceptible area. Some input data that will influence landslides, such as rainfall, wind, earthquakes, etc., was collected as the control parameters. All parts of the study area could be classified as areas with minor, medium, and major potential for landslides. Primary data are collected from geo-surveying (aerial images) using drone devices for interpretation of landslide susceptibility areas, geophysical to identify the type of soil or rock layers that completed their behavior, and slip planes as well using geo-electric, geotechnical engineering to predict slope stability with the correlation from cone penetration test (CPT) data, and geo-hydraulic to observe the rainfall and the catchment area model using the available secondary data. Geometrically, measurement data found that the average slope angle at the upper and lower of the East Java Province highway is around 40–50o. Studies from geophysical data identified that the hilly terrain in the object study area has been dominated by the weathered rock layer. Geotechnical data obtained shows the soil layers at the slope location will be stable with the water content under 35% during the dry season and may become unstable with the water content reaching over 50% due to the increase in saturation during the rainy season. The landslide that occurred was more caused by seepage behavior from surface water flow towards the sloping plane, and then the safety factor during the rainy season reached the critical values at SF = 0.58. During the dry season, the unsaturated process due to the temperature change generates a safety factor (SF) of more than 1.2. The compilation data produced maps of susceptible landslides and surface flow distribution. Doi: 10.28991/CEJ-2023-09-04-016 Full Text: PDF

Which Factors Determine the Distribution of Low-Impact Horse Logging in the Hungarian State-Owned Forests?

Nowadays, forest management focuses on nature- and environmentally-friendly methods in Europe with less fossil fuel use; however, animal-powered logging is rarely covered by scientific papers despite the fact that it is considered to be less harmful to topsoil, wood stands, saplings, and natural values than heavy machines. The main goal of this study is to determine its characteristics, advantages, and disadvantages based on structured and semi-structured interviews with loggers and foresters in every Hungarian state-owned forest area. Our results show that while 39 out of the total 116 Hungarian forest districts hired teams that applied horses for logging in 2013, their number fell to 24 in 2021. Despite this negative tendency, 34 out of the 44 forest districts that operate in hilly and mountainous areas still find horses to be useful for timber extraction. Five forest districts own horses, but none of them use animal power for logging (only for touristic and hunting activities). The productivity of a logging team depends on the timber extraction distance, terrain slope, number of workers, and cut timber volume per turn. The average logging capacity of a brigade with horses is 0.78 m3 per load, 15 m3 per day, and 2413 m3 per year. The average terrain slope angle is 15°, situated 350–450 m above sea level. The average timber extraction distance is 185 m, and the width of a track made by a horse is 96 cm. The average distance from the barn to the cut-block area is 11 km. Lower impact of horse logging on the affected area is more important than the amount of the harvested wood. Therefore, from a nature conservation aspect, it is essential to maintain animal logging and promote it with training and financial incentives.

Delineation of sensitive coastal zone of northern Ramanathapuram coast, Tamilnadu, India, using a GIS approach

This research aims to assess the sensitive coastal zones by analyzing the shoreline changes such as accretion and erosion in the eastern coastal part of Ramanathapuram District, Tamil Nadu, India. The study focused on Mandapam, Pirappanvalsai, Enmanamcondam, Nagachi, Terbogi, Athyuthu, Chitrakkottai, Pathengal, Attangarai, Alagankulam, and Devipattinam villages. Some of these areas are distinguished as highly sensitive ecological zone. The erosion of an area leads to irreplaceable disturbances to nature. Hence, erosion and accretion studies are top priorities when studying the coastal area. In addition to GIS technology, which has been widely used in the past 20 years, the End Point Rate (EPR) and Linear Regression Rate (LRR) analyses were conducted to better understand the shoreline changes. The stability of the coastal region was analyzed by observing the slope variations of the beach during the profile survey. In the study, we analyzed that the Quaternary deposits of sand are the dominant geological feature of the study area. Coral reefs and salt pans are highly distributed along the coastal stretch. The coast of Mandapam village has been detected as a highly sensitive region, with an average erosion rate of −3.1 m/yr and an average accretion rate of 1.22 m/yr, resulting in high erosion and low accretion. The coast is a steep coast with an average slope angle of 0.24°. This study provides insight into sustainable coastal zone management.

Satellite detection of snow avalanches using Sentinel-1 in a transitional snow climate

Snow avalanches endanger lives and infrastructure in mountainous regions worldwide. Consistent and accurate datasets of avalanche events are critical for improving hazard forecasting and understanding the spatial and temporal patterns of avalanche activity. Remote sensing-based identification of avalanche debris allow for the acquisition of continuous and spatially consistent avalanches datasets. This study utilizes expert manual interpretations of Sentinel-1 synthetic aperture radar (SAR) satellite backscatter images to identify avalanche debris and compares those detections against historical field records of observed avalanches in the transitional snow climates of Wyoming and Utah, USA. We explore and quantify the ability of an expert using Sentinel-1 (a SAR satellite) images to detect avalanche debris on a dataset comprised exclusively of dry slab avalanches. This research utilized four avalanche cycles with 258 field reported avalanches. Due to individual avalanches appearing in multiple overlapping Sentinel-1 images this resulted in 506 potential detections of avalanches in our SAR images, representing the possibility of multiple detections of a single avalanche event in different images. The overall probability of detection (POD) for avalanches large enough to destroy trees or bury a car (i.e., ≥D3 on the destructive size scale) was 65%. There was a significant variance in the POD among the 13 individual SAR image pairs considered (15–86%). Additionally, this study investigated the connection between successful avalanche detections and SAR-specific, topographic, and avalanche type variables. The most correlated variables with higher detection rates were avalanche path lengths, destructive size of the avalanche, incidence angles for the incoming microwaves, average path slope angle, and elapsed time between the avalanche and a Sentinel-1 satellite image acquisition. This study provides a quantification of the controlling variables in the likelihood of detecting avalanches using Sentinel-1 backscatter temporal change detection techniques, as specifically applied to a transitional snow climate.

Topographic Controls on the Distribution of Coseismic Landslides: A Case Study Using the Coefficient of Variation of the 2014 Ludian, Yunnan, China, Ms6.5 Earthquake

Abstract Identifying the locations of potential landslide areas is fundamental for disaster prevention and mitigation. Considering the close relationship between landslides and geomorphic evolution, a new approach is proposed to predict which areas are prone to landslides based on the analysis of topographic features in the area affected by the 2014 Ludian, Yunnan, China, Ms6.5 earthquake. In our method, the expected slope angle (ES), which is related to the local relief in a grid cell, is defined to describe the terrain features within grid cells. Based on the relationship between the expected slope angle and the average slope, the cells in the study region can be classified into 3 different terrains. Our study shows that large landslides triggered by the Ludian earthquake are prone to occur in regions where the expected slope angle and average slope angle show obvious differences, which means that the region has sharp changes in relief and slope. In comparison with the coseismic landslides triggered by the 2017 Jiuzhaigou, Sichuan, China, Ms7.0 earthquakes, preliminary analyses infer that the distribution of coseismic landslides follows the general mass transportation features of a special region and that their occurrences are the kind of simultaneous adjustment of excess geomorphicity of hill slopes to a steady state.

Геоинформационная оценка пространственного распределения и функционирования орошаемых земель Светлоярского района Волгоградской области

Geoinformation assessment of spatial data is carried out in order to establish the condition and location of irrigated lands on the territory of the Svetloyarsky District of the Volgograd region, as well as their geomorphological characteristics using remote sensing data, digital terrain models, soil maps. The results of the study make it possible to develop a system of socio-economic measures for the effective use of agricultural land and land management. The objectives of the study included: establishing the spatial position, geometric, soil characteristics of irrigated arable land in the study area, as well as developing a map of the distribution of irrigated land, taking into account their use. The boundaries of 1423 plots of irrigated arable land with an area of 52,300.1 hectares have been determined, with the specification of their configuration, spatial placement, relief, exposure based on remote sensing data. The average slope angle of irrigated arable land is 1.16°, the average size of the irrigated arable land plot is 36.6 hectares. The largest area of distribution (33,637.1 hectares) was received by irrigated lands on a slope steepness of 0.5°–1.0°. To a greater extent—60.8 % of irrigated lands are located on chestnut salt flats with light chestnut salt complexes. The proportion of light chestnut salty with chestnut salt is 13.5 %. On other types of soils, irrigated lands occupy from 0.6 % to 7.4 %. The calculated value of potential soil flushing in the areas of irrigated arable land most susceptible to the spread of erosion processes ranges from 6.4 t/ha to 35.1 t/ha. Obtaining data on the condition and functioning of irrigated lands on the basis of geoinformation technologies is aimed at preserving soil fertility and maintaining the conditions for the functioning of the agricultural landscape as a whole.

Hilltop curvature as a proxy for erosion rate: wavelets enable rapid computation and reveal systematic underestimation

Abstract. Estimation of erosion rate is an important component of landscape evolution studies, particularly in settings where transience or spatial variability in uplift or erosion generates diverse landform morphologies. While bedrock rivers are often used to constrain the timing and magnitude of changes in baselevel lowering, hilltop curvature (or convexity), CHT, provides an additional opportunity to map variations in erosion rate given that average slope angle becomes insensitive to erosion rate owing to threshold slope processes. CHT measurement techniques applied in prior studies (e.g., polynomial functions), however, tend to be computationally expensive when they rely on high-resolution topographic data such as lidar, limiting the spatial extent of hillslope geomorphic studies to small study regions. Alternative techniques such as spectral tools like continuous wavelet transforms present an opportunity to rapidly document trends in hilltop convexity across expansive areas. Here, we demonstrate how continuous wavelet transforms (CWTs) can be used to calculate the Laplacian of elevation, which we utilize to estimate erosion rate in three catchments of the Oregon Coast Range that exhibit varying slope angle, slope length, and hilltop convexity, implying differential erosion. We observe that CHT values calculated with the CWT are similar to those obtained from 2D polynomial functions. Consistent with recent studies, we find that erosion rates estimated with CHT from both CWTs and 2D polynomial functions are consistent with erosion rates constrained with cosmogenic radionuclides from stream sediments. Importantly, our CWT approach calculates curvature at least 103 times more quickly than 2D polynomials. This efficiency advantage of the CWT increases with domain size. As such, continuous wavelet transforms provide a compelling approach to rapidly quantify regional variations in erosion rate as well as lithology, structure, and hillslope sediment transport processes, which are encoded in hillslope morphology. Finally, we test the accuracy of CWT and 2D polynomial techniques by constructing a series of synthetic hillslopes generated by a theoretical nonlinear transport model that exhibit a range of erosion rates and topographic noise characteristics. Notably, we find that neither CWTs nor 2D polynomials reproduce the theoretically prescribed CHT value for hillslopes experiencing moderate to fast erosion rates, even when no topographic noise is added. Rather, CHT is systematically underestimated, producing a power law relationship between erosion rate and CHT that can be attributed to the increasing prominence of planar hillslopes that narrow the zone of hilltop convexity as erosion rate increases. As such, we recommend careful consideration of measurement length scale when applying CHT to estimate erosion rate in moderate to fast-eroding landscapes, where curvature measurement techniques may be prone to systematic underestimation.

Effect of viscosity on the avalanche dynamics and flow transition of wet granular matter

The dynamic behaviour of granular flows is important in geo-mechanics and industrial applications, yet poorly understood. We studied the effects of liquid viscosity and particle size on the dynamics of wet granular material flowing in a slowly rotating drum, in order to detect the transition from the avalanching to the continuous flow regime. A discrete element method (DEM) model, in which contact forces and cohesive forces were considered, was employed to simulate this flow behaviour. The model was validated experimentally, using glass beads in a wooden drum and water–glycerol mixtures to tune the liquid viscosity. The DEM simulations showed comparable results to the experiments in terms of average slope angle and avalanche amplitude. We observed that the avalanche amplitude, flow layer velocity and granular temperature decrease as the liquid viscosity increases. This effect is more pronounced for smaller sized particles. The increase in viscous forces causes the flowing particles to behave as a bulk, pushing the free surface towards a convex shape. In addition, avalanches become less pronounced and the granular flow transitions from the avalanching regime to the continuous regime. The avalanching flow regime is marked by intermittent rigid body movement of the particulate bed and near-zero drops in the granular temperature, while no rigid body movement of the bed occurs in the continuous flow regime. We identified the avalanching-continuous flow transition region as a function of a dimensionless granular Galileo number.

Safe Exploitation Solution and Reduction of Resources Loss for the L7 Seam at the West Wing Area of the 790 Open Pit Site of the Mong Duong Coal Mine

In the next time, deepening exploitation and increasing capacity in underground mines are extremely necessary to meet the demand of using coal for developing economies. This problem is not only done in underground mines but also in areas that cannot be exploited by open-pit methods such as the open-pit edge. When exploiting deep underground mines, there are many difficulties for tasks such as: controlling ground pressure; ventilation; drainage, transportation etc. When cutting coal in longwall, it will create a goaf, causing a natural imbalance of stress in the ground, leading to the phenomenon of displacement of rock deformation and destruction of roadways, which creates a risk of unsafety labour. The L7 seam at the west wing area of the Mong Duong coal mine has an average thickness of 7m, an average slope angle of 15o, located near the edge of the 790 open pit site. According to the production plan, this mine will exploit this reservoir with blasting-drilling technology, longwall support by the semi-mechanized shield (self-moving hydraulic frame GK/1600/16/24/HTD). The preliminary assessment of hydrogeological conditions of the mine shows that this is a potential area with a high risk of water burst into the longwall. Until nowthis mine has not yet given a specific solution to this problem. Finding a reasonable mining solution to ensure production safety and reduce resources loss is extremely important problem not only for the Mong Duong coal mine but also for mines that have similar mining conditions of Vietnam National Coal – Mineral Industries Holding Limited (Vinacomin), Vietnam.

Rock slope stability analysis using Slope Stability Rating (SSR) method

Nupabomba village roads frequently undergo landslides, so that detain transportation access flow pattern as a result of rock slope stability problem, which has become the landslides trigger. Furthermore, to find out landslides prone area slope stability level, an analytical study using a scientific approach is required to reveal this question in the study area. The slope elevation in this area is ± 75 meters, with an average slope angle of 60°, where its lithology consists of Schist, Greenschist, Filite, and Granite. Some of these rocks have different weathering levels (e.g., slightly - high weathering), and there are lots of discontinuity. Moreover, its geological strength index (GSI) value showed around 15-75 with the surface shape of blocky and disturbed. Besides, the uniaxial compressive strength (UCS) value was obtained based on the compressive strength carried out in the field, and slope stability rating (SSR) values have gained the range of 9-81.

Thickness Determination of a Solid Oxide Fuel Cell Blocking Layer Prepared by Atomic Layer Deposition Considering the Non-uniform Surface Geometry of Porous Substrate

The thickness of an ultrathin blocking layer for anodic aluminum oxide (AAO)-supported thin-film solid oxide fuel cells is determined. The atomic layer-deposited (ALD) ultrathin yttria-stabilized zirconia (YSZ) blocking layer for gadolinia-doped ceria (GDC) electrolyte cell is deposited on 300 nm-thick Pt anode-coated AAO substrates. The surface of AAO substrates is examined to be non-uniform in terms of pore size and bump inclination by field emission scanning electron microscopic analysis. While the average pore size is 130 nm, the pore size ranges from 36 to 207 nm. While the average slope angle is 42°, the slope angle ranges from 9° to 79°. A growth modelling result considering the pore sizes and the slope angles presents that highly reliable ALD-deposited YSZ blocking layers need to be thicker than 93 nm. This prediction well corresponds to the evolution of open circuit voltages for 400 nm-thick GDC electrolyte cells with 60 nm-thick and 120 nm-thick ALD-deposited YSZ blocking layers.

Comparison of Debris Flow Modeling Results with Empirical Formulas Applied to Russian Mountains Areas

Construction of debris flow protection structures is impossible without studying the processes first. Therefore, the purpose of this research was to calculate the magnitude of debris flows in three study areas. Initial information was provided by JSC Sevkavgiprovodkhoz and the Research Center “Geodinamika”. The first object of this research was the river Ardon and its tributary the Buddon, because of disastrous consequences for Mizur village of passed debris flows and floods. Modeling of unsteady water movement was carried out for estimation of potential flooding. During modeling, 5 cases of flash floods and debris flows of various probabilities from 0.5% to 1% percent were considered. Therefore, maximum floods for the cross-sections above and in the Mizur village itself were obtained. The second study area was the Chat-Bash stream, which is also situated in the north of Caucasus mountains. For this stream, the maximum discharge that could impact the mining complex at Tyrnyauz was determined. The third study area was the Krasnoselskaia river due to frequent floods in Yuzhno-Sakhalinsk. Applying three cases of various probabilities from 10% to 0.1%, the model determined maximum discharge and water level for the last cross-section above confluence into the Susuya river. Numerical experiments for all study areas with different roughness values were conducted to identify optimal ones. Comparing the model results for all study areas with empirical formulas (Golubcov V.V., Herheulidze I.I., Kkhann, Sribnyj and ASFS of EMERCOM of Russia) revealed that formulas contain only average depth slope angle and empirical coefficients and do not allow estimating flood areas and maximum characteristics of the event with a certain degree of accuracy.

Modelling of an accidentally triggered shallow landslide in Northern Italy

The paper presents a case study of a landslide event, accidentally triggered by an unexpected and extraordinary infiltration in an otherwise stable slope. The work aims at modelling the slope failure mechanism with a simplified two-dimensional framework based on the formation of a perched water table. The landslide occurred in Val Venosta/Vinschgau Valley, in Northern Italy, in April 2010 and produced catastrophic consequences. It took place on a hillside with average slope angle 36° and affected an area of about 200 m2; the slip surface was located approximately 1.0 m below the slope profile, in the uppermost layers of a predominantly coarse, well-graded soil. A series of numerical simulations were performed to back-analyse the event, using a commercial computer program. The artificial water infiltration and water content evolution were modelled with a two-dimensional finite element model (FE) of the unsaturated/saturated domain with appropriate infiltration boundary conditions. The slope stability analyses were conducted with a classic limit equilibrium method (LE) and were performed at different time instants during the infiltration process. The soil-water retention curves and conductivity functions were defined according to the van Genuchten-Mualem model. The combined FE and LE simulations showed the gradual formation of a perched water table, whose associated localized pore pressure distribution resulted in the loss of the suction stabilizing effect and thus in the reduction of the safety factor. Although supported by basic soil mechanical and hydraulic characterization, the numerical simulations allowed to perform a back-analysis which effectively captured the timing of the event and the location and depth of the slip surface along the slope.

Terrain Morphometry and Mudflow Features in the Northern Slope of the Great Caucasus

Morphometric terrain parameters such as slope angles and altitudes make a considerable contribution to the features of mudflows. In order to assess the contribution of these factors, this study analyzes their characteristics in the Western, Central, and Eastern Caucasus on the basis of an original digital terrain model. The average slope angles in the Western Caucasus are higher by 0.5° than those in the Central and Eastern Caucasus, thus contributing to more active mudflow. On the other hand, the Western Caucasus is distinguished by lower altitude differences. From the standpoint of this factor, the Central Caucasus is the most mudflow hazardous. Hence, the absolute altitude distribution and high forestation neutralize the factor of more significant slope angles and ensure the less considerable mudflow danger in the Western Caucasus relative to the Central and Eastern Caucasus.