Analysis of Sentinel-2A orbital imagery for the detection of deforested areas caused by artisanal mining activities in the Tapajós Environmental Protection Area, northern Jacareacanga municipality, Pará State, Brazil

Abstract. This study analyzed the advance of deforestation associated with artisanal mining in the Tapajós Environmental Protection Area (APA), north of Jacareacanga, Pará State, Brazil, for 2017 and 2024. The National Institute for Space Research (INPE) monitors deforestation in the Amazon using remote sensing, and the Tapajós APA stands out among protected areas for high rates of mining-related deforestation. Sentinel-2A images were used to generate the Normalized Difference Vegetation Index (NDVI) and RGB composites, assigning the 2017 NDVI to the red channel and the 2024 NDVI to the green and blue channels. Auxiliary data, including active mining processes in 2024 and the hydrographic network, were integrated for analysis. This approach enabled the identification of two distinct spectral responses: (i) cyan areas corresponding to regions that were non-vegetated in 2017 but exhibited regenerated vegetation in 2024; and (ii) red areas corresponding to regions that were non-vegetated in 2024. The results enabled visualization of the spatial progression of deforestation, particularly along drainage networks and in relation to active mining areas, revealing a pronounced expansion associated with artisanal mining across multiple waterways, with an upstream progression consistent with alluvial gold and cassiterite deposits. The data corroborate deforestation alerts issued by the Real-Time Deforestation Detection System (DETER) and the Deforestation Alert System (SAD)/Imazon, indicating the continuity of artisanal mining pressure in the Tapajós APA. The methodology demonstrated efficiency in detecting environmental changes and can be replicated in other areas under mining pressure, contributing to territorial monitoring and environmental management.