A Case Study of a Macro-Landslide in the High Mountain Areas of the Ecuadorian Andes: “La Cría” at the Azuay Province (Ecuador)

Abstract

Large landslides, known as macro-landslides, pose a significant threat to the safety and stability of communities living in mountainous areas. In this work, an evaluation of a macro-landslide that occurred in the La Cría community (Azuay province, Ecuador) is conducted. This macro-landslide covered an extensive area of approximately 443 hectares and affected a population that is mainly dedicated to agriculture. Historically, a landslide was already identified in the area in the 1973 geological map. However, there has recently been a significant increase in the speed of the landslide, causing damage to infrastructure and homes, and directly affecting 97 homes of various structural typologies. The study area is characterised by its geological instability, influenced by the presence of reservoirs for agriculture. In addition, the community of La Cría within the landslide has experienced considerable population growth. The study conducted combines the use of a landslide susceptibility map with a multicriteria analysis (which considers the interactions of geological, hydrological and land use) and a stability evaluation based on limit equilibrium methods. The results show that most of the territory assessed, approximately 55%, presents with a very high susceptibility to landslides, and reveal that the geology and the interactions between local geology and water resource management are needed to prevent and mitigate the risks associated with mass movements in the area.