ABSTRACT
Güímar and La Orotava valleys in Tenerife were originated by mega rockslides. The resulting slided masses, deposited on the ocean floor, cover areas of hundreds of square kilometers. These paleo-landslides have been considered as ones of the largest known in the world by their volume. Both constitute exceptional examples due to their geomorphological features and the fact that the slided deposits have been identified in the ocean floor and inside the galleries excavated in the island (Navarro & Coello, 1989). In spite of their importance, only few investigations have been carried out to analyze these processes under a geomechanical point of view. The authors are carrying out detailed studies on the geomechanical properties of the materials involved, including in situ testing and geophysical surveys, to evaluate the instability processes of the volcanic islands flanks (Ferrer et al., 2007, 2008).
