Research into landslide processes in the coastal zone of the Takhtakorpureservoir using vertical electrical sounding method (the southeastern slope of the Great Caucasus)

Landslide-prone areas on the coastal zone of the downstream of the Takhtakorpu reservoir located on the arid-hilly part of the southeastern slope of the Great Caucasus mountain system (Azerbaijan) were investigated using vertical electrical sounding (VES) method. The entire research area is geologically active. It is complicated by seismicity (with an intensity of 8—9 points on the MSK-64 scale), vertical (uplift of the Earth’s crust about +6 mm/year) and horizontal (4 ± 1 mm/year, generally north-north-east) movements, landslides (in more than 5 centers) as well as the Gaynarja mud volcano, in the form of hill ≥100 m in diameter with griffins. Tectonically, the mud volcano is timed to the consolidated part of the anticline of the same name, which currently is located in the right-bank zone, closer to the water of the Takhtakorpu reservoir. Therefore, the erupted products of the mud volcano come into contact with the aquatic environment. The geological structure of the territory is dominated by rocks of the Pliocene Productive Stratum (N2). With respect to lithology, they consist of clays and argillaceous rocks. Groundwater occurs sporadically, with a total salinity of 7 g/l and a filtration coefficient of 4 m/day. Geological sections of the area were studied to a depth of 40 m, the thickness and composition of individual layers of rocks were described. 3D models of the study area were developed completely in an arbitrary cut and also along the X, Y and Z axes. It was revealed that the layers composing the geological section of the region are subject to the impact of plicative dislocations due to the geodynamic processes. It is assumed that landslides in the study area are mainly formed at the contact of eluvial-deluvial deposits with bedrocks. One of the main reasons for the formation of landslide phenomena, apparently, is also associated with the steepness of the slopes and their constituent rocks, which absorbing atmospheric precipitation become waterlogged. The depths of the assumed slip planes in individual landslide blocks were revealed and the thickness and direction of the landslide body were determined.