Utilização do geoprocessamento como subsídio para análise morfométrica e de risco geológico das serras da porção sul do Maciço Central do Ceará

Abstract

The dissertation in question treats about GIS techniques applied to morphometric and erosion risk analysis used on ridges located in the southern portion of the Massif Central of Ceará. The ridges in question are located in the South Central region of Ceará State, between the towns of Acopiara, Piquet Carneiro, Mombaça and Catarina. This area contains a set of topographic reliefs between 500 meters to a little more than 800 meters high. These riges are supported by varios lithologies - quartzites, gnaisses, migmatites and granites, this region also features a tectonic/structural context with many deformations related to shear zones. The slopes of these relifes are all very steep, a fact that denotes concern about erosion and stability in these slopes. The use and occupation of these lands are basically applied to traditional agriculture. To better understant the geomorphological behavior of the evolution of these ridges and to determine the risks inherent to the rugged topography of the study are we used geoprocessing techiniques, such as using multi-data remote sensing and GIS tools. To better understand the geomorphological behavior of the evolution of these ridges and to determine the risks inherent to the rugged topography of the study area we used Geoprocessing techniques, such as multi-data remote sensing and GIS tools. For that four morphometric variables, through ArcGIS 10.1®, were analyzed (slope, vertical and horizontal curvatures) from DEM distinct data (ASTER-GDEM, SRTM and Topodata). The first results were presented in an article, accepted by the Brazilian Journal of Cartography, which brings the discussion about the best data/scale ratio for morphometric variables analysis. This allowed to direct the choice of MDE Topodata to generate the morphometric variables used in erosion risk analysis performed in the study area. These variables before being used as calculation basis for the erosion risk map, passed through a validation performed by field survey.