Mass Movements susceptibility in the micro basin of ribeirão Máximo, Luis Alves Municipality, SC

This dissertation aims to analyze the mass movements susceptibility in the micro basin of ribeirão Máximo, which is located at the southwest of Luis Alves municipality, in the low Itajaí Valley, northeastern Santa Catarina State, with coordinates 26°43 23.22 and 26°47 17.83 S and 48°53 16.02 and 48°57 27.96 W. The mass movements are phenomena of the earth natural morphodynamics and work in sculpture and evolution of the relief, through the detachment and transport of soil and/or rock material downward slope, by gravity action. However, the great focus on these processes takes place due to the increase of occurrences involving occupied areas with big social and environmental losses. The environmental disaster occurred in 2008 in Santa Catarina State, which affected mainly Itajaí Valley, has joined forces of the scientific community (GTC, FAPESC) in the search for understanding these phenomena that have caused so much damage and losses. In this context, Luis Alves municipality was one of the most affected, motivating the development of this research. Only in the micro basin of ribeirão Máximo were mapped 18 mass movements scars resulting from this period of intense precipitation. The work method proposed is based on the systemic analysis, adopting the watershed as the unit of analysis, with the use of theoretical work, field and lab methods, through the study and integration of local environmental specificities, climatology, geology, geomorphology, pedology, land use, in the quest for the conditioners involved in the mass movements occurrences in the micro basin of ribeirão Máximo. The environmental characteristics of the micro basin of ribeirão Máximo, humid subtropical climate with high precipitation indexes, high grade metamorphic lithologies of the Granulitic Complex of Santa Catarina State with structural lineaments and marked discontinuity plans, rugged and sloping relief with steep hillsides and deep valleys, and thick soils, added to inadequate antropic actions in hillsides, as cuts for construction of houses and roads, predispose the development of erosion and destabilizing processes. The results point the structural lineaments, the geomorphologic features, the slope and the land use as the main conditioners involved in the mass movements occurrences in the micro basin of ribeirão Máximo. The integration of these conditioners in SIG environment enabled the generation of the mass movements susceptibility map of the micro basin of ribeirão Máximo, with the hierarchization of the area in five susceptibility classes: very low, low, medium, high and very high. The detailed study of one of the 18 mass movements scars mapped in the micro basin of ribeirão Máximo allowed a wider understanding of the actuation of the conditioners involved in the occurrences of mass movements, mainly the soil behavior, confirming the low resistance of C horizon and indicating that the ruptures occur mainly in this horizonCoordenação de Aperfeiçoamento de Pessoal de Nível Superio