Morphological and geological characterization of drainage basins: contribution to landslides studies in Caraguatatuba city

Abstract

Landslides makes part, jointly with the earthquakes and floods, the natural disasters that most brings damages to humanity. The number of victims is directly related with the prepare that the city or the country has for events with this magnitude. The general object of this research is the morphological characterization of two drainage basins in the city of Caraguatatuba, in Sao Paulo State, as support for understanding landslides processes on the region. The city was chosen because of its historical occurrence of landslides, the most important being the 1967 event. Such event was triggered, between another factors, for the high rain rate on the region in a short space of time, leaving the town isolated, without communication and electric power, and thousands of people affected, having their houses destroyed, besides losses for the local economy and infrastructures. To reach the main objective of this research, it were chosen two drainage basins, the Santo Antonio's basin and the Massaguaçu's basin, once some importants morphological parameters in landslides initiation are defined in this scale of analysis (e.g. contribution area). To evaluate the influence of the morphological parameters in landslides distribution, it were selected a basin with large occurrence of landslides and another basin with less occurrence of landslides, using as criterion the volume of scars from landslides. For the confection of the morphological maps, Curvature, hypsometric, slope angle, aspect and contribution area, will be used the Digital Elevation Model (Scale 1:10.000). To assess the influence of morphological parameters in the distribution of landslides, will be used maps scars of landslides of 1967. The main products generated in this project will be maps of susceptibility to shallow translational landsliding, in scale of watersheds, based on the evaluation between geological and morphological parameters, and this processes. (AU)