Landslide Susceptibility Analysis Using 3D Modeling: A Case Study in San José de Maipo, Chile (33°38′S)

Massive landslides are rock and soil movement processes that have social, economic, and environmental impacts. Their study contributes to the balance of human settlements with the ecosystem and dynamics to mitigate and prevent risk. The intervention zone’s geomorphology, geology, precipitation, and geometry must be quantitatively considered to establish a susceptibility model. A methodology is proposed to analyze the susceptibility of mass removal with a 3D model built from aerial photogrammetry. The first step considers planning and executing a photogrammetric flight. Then, the photographic and topographic data are processed to generate a 3D model. At the same time, a map overlay is made from ortho mosaics, Digital Elevation Models, and layers. Finally, a model of transverse slope profiles is generated to determine the safety factor in San José de Maipo, Chile (33°38′S). The site presents traces and evidence of a landslide. Surface measurements of constructions, vegetation, and tension cracks were obtained. The main structural trends and depth of contact between bedrock and surface deposits detected are described. The generated models contribute to the susceptibility analysis by characterizing the landslide morphologies. Currently, it is possible to characterize undetectable removals only with Landsat imagery. The methodology is scalable to other geographic zones with geological evidence of rockslides, thus reducing uncertainty.