Morphometric parameters and debris flow: susceptibility and magnitude index to watersheds in Serra do Mar

Abstract

Debris flows are one of the most frequent types of mass movement in the region of Serra do Mar, Brazil. Thus, the goal of this study was the evaluation of the relation between the morphometric characteristics of watersheds with the occurrence of debris flow and classification using a susceptibility and magnitude index. To achieve this goal, it was used the Digital Elevation Model (DEM) Alos Palsar with 12,5 m of resolution to map the morphometric characteristics of watersheds followed by the statistical analysis and the application of a susceptibility and magnitude index. The results highlighted the parameters altimetric gradient, relief ratio, ruggedness number, basin relief, and Melton ratio in the watersheds affected by recent debris flows. The classification of the watersheds through the susceptibility and magnitude index shows similarities with the occurrence of debris flows and the susceptibility estimated, allowing its use in other susceptible areas.

Keywords:
Mass movement; Morphometric index; Debris flow.