Stability Analysis of the Volcanic Cave El Mirador (Galápagos Islands, Ecuador) Combining Numerical, Empirical and Remote Techniques

El Mirador de los Túneles is a tube-shaped volcanic cave with sinuous structure in the Galápagos Islands formed due to cooled near-surface lava flows. Since this natural formation considered tourist site, large number of people frequent it daily; however, its safety conditions have not yet been defined by comprehensive geotechnical study. In research, stability analysis was carried out combining both empirical methodologies based on geomechanical classifications using Barton’s Q Index and recently created Cave Geomechanical (CGI), numerical modeling through finite element method. addition, three-dimensional modelling performed remote photogrammetric technique Structure from Motion (SfM) create calculation sections dimensions different critical parts cave. The results showed that there evidence instability subsidence along tunnel. Furthermore, parameters obtained methods complemented each other, resulting more realistic engineering representation subsurface environment. Finally, graph showing two CGI, addition Factors Safety (FoS) presented.