Stability Analysis of a Large-Volume Block in the Historical Rock-Cut City of Vardzia (Georgia)

The rock-cut city of Vardzia (Fig. 1) is a cave monastery site in south-western Georgia, excavated inside the volcanic and pyroclastic rock layers of the Erusheti mountain on the left bank of the Mtkvari river (Gillespie and Styles 1999). The main period of construction dates back to the second half of the twelfth century. The site has been affected by frequent instability phenomena along the entire volcanic cliff (Margottini et al. 2016) that, because of their rapid evolution, are deemed dangerous to the visitors that daily crowd the site to discover its beauties. In consideration of this high risk, the National Agency for Cultural Heritage Preservation of Georgia (NACHPG) promoted, with the support of Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Geological survey of Italy, an assessment of the landslide hazard for the entire area. This paper focuses on the stability of a large rock block located in the eastern section of the site. Since this case can be considered representative of many instability phenomena at Vardzia, it is believed that the results of the present study can be beneficial to all the activities aimed to improve the safety of the area.