A relação entre os padrões de lineamentos e os movimentos de massa no município de Vitória (Espírito Santo, sudeste do Brasil)

Abstract

The main objective of this research is to analyze and relate the patterns of lineaments with the occurrence of mass movements in the municipality of Vitória (Espírito Santo, Brazil). The methodology was organized in cabinet and field analyses. In a cabinet, Lineament maps were made using the manual extraction technique, using ArcGIS 10.5 tools, on a Digital Elevation Model (DEM) with different artificial lighting (scale 1:110000) and Digital Orthophotos (scale 1:25000) and generated orientation rosettes. A Mass Movement Susceptibility Map was also produced, based on the variables density of geological structures, slope, horizontal curvature and surface coverage. In the field, the geological structures and mass movements were identified and analyzed, using the lineaments identified in the office and measurements of geological structures and lineaments (brunton compass). These data were integrated and analyzed from the records of mass movements of the Municipal Civil Defense, referring to the period between 2006 and 2020. It was possible to verify the orientation patterns of dominant geological structures in the area (NNW-SSE and NW-SE, followed by by NE-SW). On the regional scale, there were more mass movements in the vicinity of lineaments of NNW-SSE, NW-SE and NE-SW orientations, on the regional scale these processes occurred more frequently in the vicinity of lineaments of orientations NNW-SSE, NNE-SSW and NE-SW. The analysis of structural data, at the local or regional scale, with the occurrence of mass movements was carried out by studying their relationship with lineament data, lineament density and geological structures, Faixa Colatina, Araçuai Orogen and neotectonic faults. In the mass movement susceptibility map produced, 78.72% of the recorded mass movements occurred in areas of Very High, High or Medium susceptibility. The variable density of geological structures proved to be of great value for the elaboration of mappings of susceptibility to mass movements, since the increase in density is directly proportional to the occurrence of these processes, with the exception of Very High density, which has low spatial representation.