Fourth EAGE Workshop on Assessment of Landslide Hazardsand impact on communities

The applied technique for considering the dynamic effects on geotechnical structures in the compacted urban development conditions with the direct dynamic calculations and taking into account the experimentally obtained accelerograms is developed. The method includes the visual and vibrodynamic inspections of the new building in the existing geotechnical environment and of the vibrodynamic influence sources. The determination of the soil and building structures dynamic characteristics is based on their free vibrations with small amplitudes caused by natural or man-made microseisms and includes the vibrations recording by means of the highly sensitive (in our case - accelerometric) sensors; the Fourier spectra calculations and analysis in order to isolate the resonance peaks corresponding to the various forms of the free vibrations; the inverse Fourier transform use for obtaining the impulse implementations of the selected resonance peaks for each form of the design free vibrations; the identification and graphical representation of the various forms vibrations of the investigated soil, geotechnical structures, etc. The vibrodynamic investigations of the soil and individual buildings structures at the Poshtova Square for the determination of the actual dynamic loads on the soil and pit retaining walls at the construction site are exemplified.

The methodology for calculating the stability of the base of reinforced concrete slabs of bank slopes is proposed. For slabs facing slopes, the main and temporary loads and influences include the self-weight of the fastener; water pressure directly on the surface of the slope, the force of filtration water at a normal supported level; the pressure of deposited sediments; temperature effects of the construction and operational periods; wave pressure, determined by the average multi-year wind speed; ice pressure, which is determined by the average multi-year ice thickness; wind loads. Special loads are considered to be the force of filtration water on the boundary of the waterproof section of the building; loads caused by excess pore pressure under forced water level; temperature effects, which are determined for the year with the largest amplitude of fluctuations in the average monthly air temperature; wave pressure, which is determined by the maximum calculated wind speed; ice loads determined by the maximum multi-year ice thickness; and seismic effects. Such hydro-technical constructions are used, usually, in case of significant deformation of the soil at the base of the slope to prevent landslides and protect the slopes of the banks of water bodies from destruction by currents and waves, to reduce the roughness of the live section of water bodies.

The combination of natural and man-made factors is a prerequisite for the formation of man-made cracks. The short duration of the generator and the high leading edge of the excited pulse create good prerequisites for using acoustic emission effects to study rock samples. The use of a sensitive acoustic emission method makes it possible to establish the main features of cracks development in the stress-deformed state of rocks. Therefore, this study aimed to demonstrate the effectiveness of the acoustic emission method from the perspective of establishing the main genetic types of cracking, the dynamics of their formation, and, if possible, the quantitative ratios between them. These characteristics provide information regarding the dangers of landslide processes. The determination of crack-pore zones using the acoustic emission method is of great interest when assessing the residual technical condition of various types of structures. In particular, hydrotechnical and land reclamation due to regular water infiltration processes, which leads to an increase in the risk of landslides. In addition, many opportunities are available for the prediction of the strength and stress states using the acoustic emission method.

The publication provides the results of research on the effects of the earthquake in Indonesia on 28 September 2018 using satellite images. A very powerful earthquake with a magnitude of 7.5 on the Richter scale occurred in Indonesia near the city of Palu on the island of Celebes (Sulawesi). The earthquake caused a tsunami and landslides in the densely populated city, leading to widespread destruction and casualties. The research was conducted using the EO Browser platform ( Sentinel-hub, 2015 ) from the European Space Agency and available online satellite images of the Sentinal-2 optical satellite for two dates: before the earthquake (27.09.2018) and after (02.10.2018). The use of multi-temporal imagery has enabled us to compare the conditions of the area before and after the disaster, and to assess, in the short and long term, the impact of the devastating earthquake and the resulting negative effects, such as tsunamis and landslides.

Landslide susceptibility maps are essential in sustainable land planning and landslide risk management. In recent years, remote sensing data and GIS have been commonly used to map landslide morphology and estimate landslide activity. The research presents processing the digital elevation models (DEMs) by geoinformation technologies, which in turn makes it possible to analyze the conditions of landslides within study areas of Poland and Ukraine and build analytic maps.

The distribution of various types of landslides of the Slavska Verkhovyna of the Vododilno-Verkhovyna Ukrainian Carpathians was investigated. The methods of own field observations over many years, analysis of aero- and space materials, reports of a geological exploration expedition, GIS analysis were used. The morphometric parameters and conditions for the development of large, medium and small landslides were studied. Analyzing morphometric maps of the localization of landslides in QGIS, the number of landslides by mode of movement was calculated. Earthflow together with the transitional types (translational & earthflow) predominate and make up 66% of all landslides. Landslides are located on slopes with a steepness of 15–20°. According to the exposure, the largest landslide areas are located on the slopes of the northeastern and southwestern exposures. 60% of earthflow and transitions, 19% of block-slide and 15% translational is located on the lower parts of the ridge slopes and valley slopes. We have determined that the most dangerous frontal block-slide and circus-shaped translational large landslides, their activation mostly occurs in the lower parts of the mountain slopes also, where economic activities are conducted.

In the research, the use of numerical simulation of the loss of slope stability and the analysis of warning factors of the landslide hazard is proposed to identify the unstable and potential landslide hazard areas. The study area is the slopes of the Far-caves Hill, in the soil massif of which the Far and Varyaz caves of the Kyiv-Pecherska Lavra are located. The initial data were the scheme of engineering protection of the territory (scale 1:1000); the plan of the current state of the Reserve (scale 1:1000); the geodetic plan (scale 1:500); data of engineering and geological investigations, etc. Numerical methods were used to calculate slope stability under boundary conditions on geological profiles above the Varyaz Caves. Slope stability calculations were performed for two soil conditions – natural and predicted water-saturated states. The results of the calculations show that the slope is stable in the natural state of the soil (kst = 1.302, with a standard value of 1.25) and loses stability when water is saturated (kst = 0.988 and 1.100). The obtained contours of the possible manifestation of landslide hazards are necessary for the development of design solutions for the protection of UNESCO cultural heritage sites both into the slope massives and on the surface of the Far-caves Hill.

The mechanism of discharge of excess surface water in the geological environment is considered on the example of a quarry in the south of Kryvbas. They can lead to dangerous landslide processes in the form of collapses of the sides of pits, dumps, slurries, causing significant damage to the enterprises, to agricultural lands and the population.

In 2021, field observations were carried out to assess the impact of mining operations in the quarry on the Ingulets River (the right tributary of the Dnipro River) using the methods of electrical exploration (various modifications), natural field and gravity method. Processing of the results of field geophysical observations was carried out by the method of comparative statistical analysis of previously obtained and current data.

In the course of research, the impact of the release of huge volumes of water from the Karachun Reservoir into the Ingulets River was recorded and studied, which caused a significant and rapid rise in the water level in the river and waterlogging of the quarry slopes with ground water. The obtained results showed how the hydrogeodynamic process in underground waters occurs during significant surface water irrigation of the sedimentary cover in areas with open and closed fault systems.

The obtained results confirmed the possibility of conducting research using the method of natural field to study the mechanism of rapid water saturation with waters of the geological section and ways of their discharge. The method showed the prospects of its application in areas with open and closed fault systems.

The NF method is not expensive and operational, which makes it possible to use it at the initial stage of monitoring to identify the zone of detected landslide development.

The mechanism of discharge of excess surface water in the geological environment is considered on the example of a quarry in the south of Kryvbas. They can lead to dangerous landslide processes in the form of collapses of the sides of pits, dumps, slurries, causing significant damage to the enterprises, to agricultural lands and the population.

In 2021, field observations were carried out to assess the impact of mining operations in the quarry on the Ingulets River (the right tributary of the Dnipro River) using the methods of electrical exploration (various modifications), natural field and gravity method. Processing of the results of field geophysical observations was carried out by the method of comparative statistical analysis of previously obtained and current data.

In the course of research, the impact of the release of huge volumes of water from the Karachun Reservoir into the Ingulets River was recorded and studied, which caused a significant and rapid rise in the water level in the river and waterlogging of the quarry slopes with ground water. The obtained results showed how the hydrogeodynamic process in underground waters occurs during significant surface water irrigation of the sedimentary cover in areas with open and closed fault systems.

The obtained results confirmed the possibility of conducting research using the method of natural field to study the mechanism of rapid water saturation with waters of the geological section and ways of their discharge. The method showed the prospects of its application in areas with open and closed fault systems.

The NF method is not expensive and operational, which makes it possible to use it at the initial stage of monitoring to identify the zone of detected landslide development.

SUMMARY. The paper presents the findings of a study focused on assessing soil erosion risk within the agro-landscapes of the Forest-Steppe of Ukraine, specifically within the Buziv Head Dstrict of the Dmytriv Territorial Community of the Kyiv oblast. The methodology employed in this study involved the utilization of remote sensing data and geoinformation technologiesas well as the application of the Revised Universal Soil Loss Equation (RUSLE) model.

It has been established that the implementation of the RUSLE model makes it possible to obtain complex geospatial data on the differentiation of agricultural landscapes in the study area, which is based on the calculation of soil erosion intensity over a one-year period. The analysis reveals that: (1) approximately 37.7% of the soil cover area is associated with minimal risk of soil erosion loss (≤ 0.5 t/ha per year); (2) roughly 48.2% of the area experiences insignificant erosion rates (0.5 – 5.0 t/ha per year); (3) about 5.7% of the land exhibits moderate erosion (5.0 – 15.0 t/ha per year); (4) approximately 6.7% of the terrain faces significant erosion (15.0 - t/ha per year); (5) a smaller portion, constituting 1.7% of the area, is subjected to severe erosion (> 50.0 t/ha per year).

Notably, the areas with the highest levels of erosion risk are predominantly found within agrolandscapes characterized by complex topographical features and situated in close proximity to Buzova river floodplain.

The application of the RUSLE model has enabled the identification of land parcels with varying degrees of erosion risk over a defined time frame. This information holds significant value for forecasting potential alterations in erosion processes within the region. Furthermore, it can serve as a valuable resource for farmers, aiding them in the strategic localization of erosion control efforts.

This paper focuses on landslide monitoring to detect landslide-prone areas using remote sensing data. We exploited the Differential Interferometry Synthetic Aperture Radar (DInSAR) methodology to assess the distribution of potentially dangerous landslide areas under conditions of intensification of precipitation and the influence of the temperature regime on soils. The study area is located in dissected loess-like upland within the right bank of the Kaniv Reservoir, which belongs to Rzhyshchiv urban hromada. Taking into account the geological data of the studied region, we can assess the stability of the slopes and determine the potential risks of landslides. The obtained research results will improve the understanding of geological processes and the distribution of potentially dangerous landslide-prone areas in the studied region. Our study will make it possible to develop effective safety measures and prevention of landslide risks to ensure the safety of residents and infrastructure in this region.