Carta de suscetibilidade a movimentos gravitacionais de massa do município de Ubatuba-SP
Arquivos
Data
2022-02-10
Autores
Leal, Augusto Henrique Ribeiro 
Orientadores
Soares Junior, Adilson Viana
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O crescimento desordenado dos centros urbanos geralmente culmina na ocupação irregular de áreas consideradas suscetíveis a movimentos gravitacionais de massa, como as encostas. O estabelecimento de comunidades humanas nestas áreas põe em risco a vida das pessoas e promove a depreciação do compartimento do solo e consequentemente da paisagem. Desta forma, o mapeamento de áreas suscetíveis é imprescindível para nortear o Poder Público na elaboração do planejamento urbano e na execução de políticas públicas. Este trabalho trata da elaboração de uma Carta de Suscetibilidade a Movimentos de Massa para o município de Ubatuba, localizado no litoral norte do estado de São Paulo, realizada através de imagens de sensoriamento remoto e de informações geológicas, e processadas por meio de ferramentas de geoprocessamento. Foram utilizadas imagens de satélite óptico (Landsat 8), imagens de radar (Shuttle Radar Topography Mission – SRTM) e mapas geológicos. Existem diversos fatores condicionantes que podem interferir no grau de estabilidade das encostas, sem dúvida o mais importante é a declividade, entretanto, a litologia, o uso do solo, curvatura vertical e a densidade de lineamentos também são importantes. Neste estudo, foi elaborado um mapa para cada um dos fatores condicionantes considerados, de modo que, cada pixel de cada mapa foi reclassificado com valor numéricos entre 1 e 5, sendo que, o valor numérico 1 classifica a área como de risco baixo e 5 como de risco alto. Desta forma, a carta de suscetibilidade foi elaborada a partir da álgebra dos mapas elaborados para cada fator condicionante, sendo que, os resultados obtidos foram classificados em três classes de suscetibilidade: baixa, moderada e alta. Os resultados mostraram o predomínio de áreas de suscetibilidade alta com 48%, e baixa com 30% do território do município. Áreas com suscetibilidade moderada ocupam 22% do total do território. As áreas de suscetibilidade baixa estão relacionadas com declividades baixas que variam entre 0 e 5%, associadas às regiões suportadas por sedimentos marinhos e às áreas urbanas consolidadas. As áreas com grau de suscetibilidade moderada e alta estão relacionadas com declividades acima de 12%, suportadas por rochas metamórficas, sendo predominante os migmatitos, e áreas de mata densa.
The disorderly growth of urban centers usually culminates in the irregular occupation of areas considered susceptible to gravitational mass movements, such as slopes. The establishment of human communities in these areas puts people's lives at risk and promotes the depreciation of the soil compartment and consequently the landscape. In this way, the mapping of susceptible areas is essential to guide the Public Power in the elaboration of urban planning and in the execution of public policies. This work deals with the elaboration of a Mass Movement Susceptibility Chart for the municipality of Ubatuba, located on the northern coast of the state of São Paulo, carried out through remote sensing images and geological information, and processed through geoprocessing tools. . Optical satellite images (Landsat 8), radar images (Shuttle Radar Topography Mission – SRTM) and geological maps were used. There are several conditioning factors that can interfere with the degree of stability of the slopes, undoubtedly the most important is the slope, however, lithology, land use, vertical curvature and the density of lineaments are also important. In this study, a map was prepared for each of the conditioning factors considered, so that each pixel of each map was reclassified with numerical values between 1 and 5, with numerical value 1 classifying the area as low risk and 5 as high risk. In this way, the susceptibility chart was elaborated from the algebra of the maps elaborated for each conditioning factor, and the results obtained were classified into three susceptibility classes: low, moderate and high. The results showed the predominance of areas of high susceptibility with 48%, and low with 30% of the territory of the municipality. Areas with moderate susceptibility occupy 22% of the total territory. Low susceptibility areas are related to low slopes that vary between 0 and 5%, associated with regions supported by marine sediments and consolidated urban areas. Areas with moderate and high degree of susceptibility are related to slopes above 12%, supported by metamorphic rocks, predominantly migmatites, and areas of dense forest.
The disorderly growth of urban centers usually culminates in the irregular occupation of areas considered susceptible to gravitational mass movements, such as slopes. The establishment of human communities in these areas puts people's lives at risk and promotes the depreciation of the soil compartment and consequently the landscape. In this way, the mapping of susceptible areas is essential to guide the Public Power in the elaboration of urban planning and in the execution of public policies. This work deals with the elaboration of a Mass Movement Susceptibility Chart for the municipality of Ubatuba, located on the northern coast of the state of São Paulo, carried out through remote sensing images and geological information, and processed through geoprocessing tools. . Optical satellite images (Landsat 8), radar images (Shuttle Radar Topography Mission – SRTM) and geological maps were used. There are several conditioning factors that can interfere with the degree of stability of the slopes, undoubtedly the most important is the slope, however, lithology, land use, vertical curvature and the density of lineaments are also important. In this study, a map was prepared for each of the conditioning factors considered, so that each pixel of each map was reclassified with numerical values between 1 and 5, with numerical value 1 classifying the area as low risk and 5 as high risk. In this way, the susceptibility chart was elaborated from the algebra of the maps elaborated for each conditioning factor, and the results obtained were classified into three susceptibility classes: low, moderate and high. The results showed the predominance of areas of high susceptibility with 48%, and low with 30% of the territory of the municipality. Areas with moderate susceptibility occupy 22% of the total territory. Low susceptibility areas are related to low slopes that vary between 0 and 5%, associated with regions supported by marine sediments and consolidated urban areas. Areas with moderate and high degree of susceptibility are related to slopes above 12%, supported by metamorphic rocks, predominantly migmatites, and areas of dense forest.
Descrição
Citação
LEAL, A. H. R., 2022