remote sensing Article Applying Close Range Non-Destructive Techniques for the Detection of Conservation Problems in Rock-Carved Cultural Heritage Sites William Frodella 1,2,* , Mikheil Elashvili 3, Daniele Spizzichino 4, Giovanni Gigli 1,2, Akaki Nadaraia 3, Giorgi Kirkitadze 3, Luka Adikashvili 3, Claudio Margottini 2, Nikoloz Antidze 5 and Nicola Casagli 1,2, 1 Earth Science Department, University of Florence, Via G. La Pira 4, 50121 Florence, Italy; giovanni.gigli@unifi.it (G.G.); nicola.casagli@unifi.it (N.C.) 2 UNESCO Chair on Prevention and Sustainable Management of Geo-Hydrological Hazards, University of Florence, Largo Fermi 1, 50142 Florence, Italy; claudio.margottini@unifi.it 3 Faculty of Natural Sciences and Engineering, Ilia State University, Kakutsa Ave 3/5, 0162 Tblisi, Georgia;
[email protected] (M.E.);
[email protected] (A.N.);
[email protected] (G.K.);
[email protected] (L.A.) 4 Institute for Environmental Protection and Research (ISPRA), ia V. Brancati 48, 00144 Rome, Italy;
[email protected] 5 Georgian the National Agency for Cultural Heritage Preservation of Georgia (NACHPG), 27 Atoneli Street, 0105 Tbilisi, Georgia;
[email protected] * Correspondence: william.frodella@unifi.it; Tel.: +39-055-275-5979 Abstract: Rock-carved cultural heritage sites are often developed in slopes formed by weak rocks, Citation: Frodella, W.; Elashvili, M.; which due to their peculiar lithological, geotechnical, and morpho-structural features are character- Spizzichino, D.; Gigli, G.; Nadaraia, ized by excellent carvability, which at the same time makes them prone to weathering, deterioration, A.; Kirkitadze, G.; Adikashvili, L.; and slope instability issues.