Identification of the affected areas by mass movement through a physically based model of landslide hazard combined with a two-dimensional flood routing model for simulating debris flow

Natural disasters are one of the world´s greatest socioeconomic problems and one of the most notable of which is that of mass movements, which are natural phenomena that change the relief and cause great damage to mankind. Mass movements can be classified by: type of material involved, velocity and mechanism of movement, type of deformation, geometry of the displaced mass and water content. Among them, the shallow landslides stand out. These movements are triggered during intense rainfall, frequently in the summer. Shallow landslides transform into debris flow mainly due to water infiltration. They reach long distances, velocity and high transport capacity, including large boulders. It is essential not only to predict shallow translational landslides but also to predict debris flow occurrence and runout as a secondary effect. The aim of this study is to develop a methodology which combines a model to predict landslides with another one that determines debris flows pathways and depositions. The study area is located in the west slope of Macico da Tijuca, involving the Quitite and Papagaio river basins, in the Jacarepagua neighbourhood of Rio de Janeiro, Brazil.