Second EAGE Workshop on Assessment of Landslide Hazards and impact on communities

The development and prevalence of landslides within territories of the southwestern outskirts of the East European Platform, the Pre-Carpathian Deflection and the Carpathian region of Ukraine are explained by geological, structural-tectonic, lithological-stratigraphic and geomorphological features, neotectonic, hydrogeological and seismic regimens, as well as the degree of technogenic impact. The activity of the landslide process is closely related to precipitation and temperature regimes, changes in groundwater levels, etc. Activation of landslides is often associated with the development of other exogenous processes (erosion, flooding).

Within the abovementioned geostructural regions, geological processes differ in intensity, dynamics and area of distribution, which is associated with conditions of their development.

Forecasting changes of the state of geological environment consists of forecast estimates of separate geological processes, on the one hand, and forecast estimates of the stability of geological environment as a result of technogenic changes in natural-technogenic systems of different ranks, on the other hand. Landslide forecasting is conducted from the standpoint of systematic approach. The implementation of this approach allows to identify a complex of links that reflect the direction of development of natural-technogenic systems according to the following aspects: stability of the geological environment (subsurface part of the lithosphere) under the influence of external agents, including technogenic activities; adaptation of natural-technogenic systems in their development; self-regulation of the natural-technogenic system given changes or stability of external influence.

The consideration is given to the results of application of a complex of geophysical methods for the purpose of local forecasting of landslide hazards within the flooded quarry, named Glynka Lake (Kyiv, Ukraine). One of the regions of active development of landslides in Ukraine is Kyiv, where the mass movement processes have significant impact on people’s livelihoods and infrastructure. These landslide processes occur on slopes of different structure and morphology. Currently, the territory of the starboard side of the Glynka Lake is one of the most dangerous landslides in Kyiv and poses a threat to infrastructure facilities on the towards Akademika Filatova Street and Mendeleeva Street. Electrical Resistivity Tomography, Self-potential, Infrared Thermography and ground penetrating radar (GPR) techniques were applied to investigate the lithostratigraphic sequences, the geometry of landslide body and potential mass movement. These methods allowed to define the composition and structure of the landslide, as well as to identify moisture or a seepage zones on the landslide slope. GPR method was showed borders between different deposits layers and possible surface of rupture. This study demonstrates the potential of using an integrated approach for landslide characterization in the regions with complex geological structure.

Due to global warming, the glaciers and ice systems of Antarctica and the Antarctic peninsula have undergone significant changes in shape and size in recent decades. Therefore, it is necessary to constantly monitor and analyze changes in the basic parameters of glaciers and ice systems to control, predict and prevent such processes. This study presents preliminary results of the analysis of changes in the marine-terminating part of Trooz Glacier (West Antarctica) during 2001–2020. The study used freely available satellite images from different times (Mapper Plus Landsat-7 and Landsat-8 Operational Land Imager). As a result of analysis, filtering and processing of the original data obtained in part of Trooz Glacier in different periods of research. It has been established that the marine-terminating part of Trooz Glacier is exposed to systematic landslide processes that have a north-westerly direction.

Purpose of the work has been to reveal spatial and temporal regularities of micro-block geodynamics to bring down engineering and construction risks on landslide slopes of Odesa coast. Methodology. The results of the slope landslide mapping (1953), geodetic monitoring (1966 – 1992) and instrumental measurements of deformations (2018) of constructive elements of an offtake drift in Odesa coast landslide protection works have been used as the source data. Data processing comprised determination of benchmarks’ movement and horizontal displacement, incline parameters of the offtake drift water-sink and deviation of the drift cross sectional diameters from the standard one. Results. It has been established that the drift could be divided into separate segments (blocks of rock massif), which experience rises, inclinations and differentiated movements. The deformations of the drift water-sink and constructive elements that have accumulated during service life are well pronounced. They have the form of zones of local creepage formed as the result of micro-blocks differentiated movements. Conclusions. The structural and geological basis of landslide processes is permanently active as the result of micro-blocks constant movements creating conditions for the slopes stability decrease. Optimal construction solutions should be tailored for current engineering geodynamics of landslide slopes.

The Department of Earth Science and Geomorphology of the Faculty of Geography of the Taras Shevchenko National University of Kyiv from the 90’s of the 20th-century has been conducting systematic field and semi-stationary studies of the natural system of the upper part of the Chorna Tysa River basin (Halahan et al, 2019). In the winter and spring of 1999, due to the natural and natural-anthropogenic factors, there was a natural disaster at the local level. It affected the natural complex of the territory including morphosystem as its most stable element.

Studies of morphosystems of the upper part of the Chorna Tysa River basin allowed us to draw a number of conclusions. Basin morphosystems continue to persist within their spatial boundaries. They continue to build their structure which combines modern and ancient morphological elements. Basin geomorphosystems show the “ability” to withstand external influences. The stage of quiet evolutionary development (bifurcations) was replaced by the stage of stabilization of one stable position of the channel. Transportation and accumulation on the slopes at the bottom often depended on random causes (eg, the presence of fallen trees, man-made structures). They also depended on the genetic types of slopes and their attachment to vegetation (forest or grass). If the genetic types of slopes did not change much in the hypsometrical higher areas (often covered with shrubs, grass, moss), then in the case of thalweg there are many such cases, especially in the lower part of the basin. In particular, in the starboard side near the exit to the valley of the Chorna Tysa River, a case of replacement of the defluxion slope (covered with forest) with a bare landslide was recorded. The basin geomorphosystems of the Apshinets River, in contrast to other basin formations, has practically recovered in a few years and, thanks to new morphological qualities, will be able to withstand future natural disasters.

Landslides, volcanic debris and mud flows are the most frequently occurred common geohazards in the Region of Great Ararat Volcano. Most geohazards are triggered or re-activated by earthquakes. This Region well known in literature as Turk-Iran High Volcanic Plateau (TIHVP) which located in front of Arabian-Eurasian Collision Suture. High seismicity and high relief due to young volcanism influenced mass movements. Landslides are frequently triggered by seismic shocks and developed by decreased slope stability due to active fault displacements. Telceker Landslide has been studied first by remote sensing and near surface geophysical techniques, by a joint research team from US-Los Alamos National Laboratory. Detailed geology, morphotectonic features and active tectonics of a landslide and surrounding area were studied. Telceker landslide subsidence started at the Turk-Iran border, water-divide line. Collapsed debris flowed northwards down along the valley and deposited near Telçeker Village at Doğubayazit Plain. The dominant character of the landslide mass is dominantly debris flow and currently active Mud Flow, at upper stages. The western margin is defined by a north-northeast striking left slip oblique Maşer Fault. Several ponds, swamp areas, longitudinal ridges, and transversal cracks, concave scarp structures have formed. Three segments of landslide are distinctly recognized along flow-direction. At the center, a Mud Flow continues through a narrow channel-like corridore, leaving lens-shaped huge fragments behind at the entrance to the corridor, 350 m wide and approximately 2.0 km long. A third segment is represented by deposition-accumulation of debris at the foot (toe) which crosses the Doğubeyazit Fault scarp where turns East (at sharp angle) resulted by right lateral displacement of the DB fault zone. Coarse debris spread down into the Doğubeyazit Plain in a fan-like geometry due to the high slope angle. Three stages of landslide activity are recongized, particularly at the lower part of corridor and at foot area. These stages are recognized by ground data based on textureal difference in topography, morphology, and degree of consolidation.

Consideration is given to newest geodynamics and related geological hazards in the Middle Dnieper Region (Ukrainian Shield). Reconstruction of the tectonic movements is based on the complex structural-morphometric techniques, remote sensing data and GIS-analysis. Three structures (Kyiv, Obukhiv, Kaniv-Trakhtemiriv blocks) have been identified and characterized. Quantitative indicators of landforms during each stage are determined, the total amplitudes of oscillations are analyzed both for short time intervals and for the whole Neogene-Quaternary period. In general, the amplitude of vertical tectonic movement within the Middle Dnieper region in the Neogene-Quaternary period in the northern part was 100 m, in the southern part was 135 m. It was confirmed that the northern part of the region had an active upward dynamics of movements in the Neogene period, and the southern part had the same dynamics in the Quaternary period. The obtained data is the basis for the analysis of the influence of tectonic movements on the activation of natural hazards processes within the Middle Dnieper area and the prediction of their development in the future.

The choice of the Western part of Polonyna Borzhava for the construction of wind farms stems from the highest wind energy potential in Ukraine in the Carpathian region, which was mentioned in the planning scheme of the Transcarpathian region. Determinants of the complexity of engineering and geological conditions in the study area are mountainous terrain, its high absolute marks - from 1100 to 1700 m above sea level, significant steepness of slopes, seismicity of the Carpathian region and proximity to the Vrancea zone, heterogeneity and mostly monoclinic occurrence of flysch. Selected areas for the construction of 34 wind turbines are characterized by minimum values of the thickness of Quaternary sediments from a few centimeters to 3.5 m, with most future construction sites not exceeding 1 m. The project of construction of a 120 MW wind farm, laying of high-voltage cable, reconstruction of the road will be developed based on the principles of minimizing the negative impact on the environment, maximum preservation of soil and vegetation layer using ecomat technology, trenchless cable laying technology and maximum removal and preservation is technically possible to do, namely the removal and temporary storage of turf in 34 allotted areas with industrial turf, which can cut the turf into strips to a depth of 8–10 cm, suitable for twisting into rolls and temporary storage in the area of 10x30 m on the periphery of each plot.

Comprehensive engineering-geological and hydrogeological surveys conducted by Geol-Tech LLC showed that the geological factor influences as the main protector from possible unfavorable scenarios of landslides and mudflows, which together with the envisaged engineering protection measures, practically prevents negative consequences.

One of the biggest challenge all over the world is assessment of the natural and anthropogenic hazards. Landslides are one of the most dangerous processes, which is related to the accelerated linear erosion and hydromorphism of the soil. Magnetic method is low cost and rapid instrument for the soil erosion identification. The main parameter to access soil erosion is magnetic susceptibility χ (MS). The soil erosion was studied on the example of the agro-physical observation point “Slobozhansky” (Balakliysky district, Kharkiv region). Study area is characterized by significant vertical dissection of the terrain and the spread of erosion processes. We registered the decrease in MS values, which correspond to the eroded areas, the lower part of the slope and the runoff basin. Much more complicated is the interpretation of the magnetic characteristics of soils in cases of the combined impact to the soil degradation. Among the main factors, which have strong impact on soil magnetism, are combined hygromorphic and halomorphic processes. Such processes were studied at the area of the valley of the Sula River (Lokhvytskyi district, Poltava region). The MS of chernozem deep-leached soil at the depression is much lower (over 60%) than the background MS of the chernozem deep residual-deep-saline soil.