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The mountainous region of Greater Sochi, including the Olympic ski-jump complex area, located in the northern Caucasus, is always subjected to landslides. The weathered mudstone of low strength and potential high-intensity earthquakes are considered as the crucial factors causing slope instability in the ski-jump complex area. This study aims to conduct a seismic slope instability map of the area. A slope map was derived from a digital elevation model (DEM) and calculated using ArcGIS. The numerical modelling of slope stability with various slope angles was conducted using Geostudio. The Spencer method was applied to calculate the slope safety factors (Fs). The pseudostatic analysis was used to compute Fs considering seismic effect. A good correlation between Fs and slope angle was found. Combining these data, sets slope instability maps were achieved. Newmark displacement maps were also drawn according to empirical regression equations. The result shows that the static safety factor map corresponds to the existing slope instability locations in a shallow landslide inventory map. The seismic safety factor maps and Newmark displacement maps may be applied to predict potential landslides of the study area in the case of earthquake occurrence.

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Justification of seismic triggering of large prehistoric rockslides that originated on the slopes of anticlinal ridges armoured by thick carbonate units has been performed by examples of the gigantic Seimareh rockslide in Zagros (Iran) and two structurally similar, though much smaller rockslides in Dagestan (Greater Caucasus, Russia). Such structural and geomorphic conditions allow precise reconstruction of the pre-slide topography of the studied sites that increases reliability of their back analysis significantly. Linear dimensions of landslides are much larger than thickness of the siding block that makes the simplified 2D numerical modelling of these slopes quite realistic. The pseudostatic analysis performed at the first step confirmed that the study slopes could not fail without strong earthquakes. However, further dynamic analysis performed by use of the Newmark method allowed estimating characteristics of strong motions that could result in formation of rockslides that had converted in long runout rock avalanches. Possible uncertainties and open problems are discussed as well.

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