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

Geological lineaments are linear or curvilinear surfaces that are considered a superficial expression of discontinuities on the earth’s surface. The extraction of lineaments from remotely sensed satellite data is one of the most frequently used applications of remote sensing in geology. This study focuses on the semi-automatic extraction of lineaments in the Girón–Santa Isabel basin using a Topographic Position Index (TPI). The lineaments were extracted in the PCI Geomatics 2016 software and analyzed in the ArcGIS and Rockworks software. Statistical and density map analyses of the lineaments were performed; then, these results were interpreted to obtain the geological lineaments. Finally, a bibliographic verification was carried out, and structures such as faults and folds were defined. The total number of geological lineaments was 76, and 71 of them were defined as faults, the longest with a length of 33 km. It was determined that the preferential orientation of the lineaments is NE–SW, which is consistent with the axis of the Girón–Santa Isabel basin. This methodology can be useful to optimize time and reduce costs when gathering the structural information of the study area in the first stage of geological and mining prospecting or the educational field.