Uso de imagens do OLI/Landsat 8 no estudo de desastres ambientais: estudo de caso do rompimento da barragem em Brumadinho – MG

• Autor(a) principal: Lucchetta, Beatriz Cirino
• Data de Publicação: 2021
• Outros Autores: Oliveira, Fernanda Silva
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/216304
• topic: Remote sensing; Geoprocessing; Spectral indexes; Environmental disasters; Dam rupture; Sensoriamento remoto; Geoprocessamento; Índices espectrais; Desastres ambientais; Rompimento de barragens

The rupture of the B1 dam of iron ore tailings at the Córrego do Feijão mine, in Brumadinho - MG, associated with the mining company Vale SA, was one of the biggest environmental disasters in Brazil, causing hundreds of deaths and devastating with its mud of tailings an area of almost 297 ha, contaminating the Paraopeba River, affecting several municipalities, flora and fauna. In this work, the objective was to identify the area affected by mining tailings mud through techniques of digital image processing and geoprocessing. We analyzed the performance of different spectral indexes: Normalized Vegetation Difference Index (NDVI), Simple Ratio Index Ferrous Minerals and Simple Ratio Index Clay Minerals. Two images of the Operational Land Instrument (OLI) sensor, from the Landsat 8 satellite, were acquired on a date before and after the dam burst. These indexes were selected due to the removal of vegetation from the site by the tailings sludge composed of iron ore, silt, silica and clay, ensuring that the image after the rupture could identify the affected area. After applying the indices, a slicing operation was carried out to delimit the affected area through intervals that adequately showed the region. After delimiting the region, the area and perimeter of the polygon resulting from the slicing of each index was calculated. Finally, a comparison was done with the polygon of the delimited area provided, by the Brazilian Institute of Geography and Statistics (IBGE), to verify which index obtained the best performance and it was determined that the NDVI and the Simple Ratio Index Ferrous Minerals showed the best performances.