Avaliação do MDE gerado pelo sensor Palsar/Satélite Alos, como alternativa para o zoneamento de áreas de risco a escorregamentos em locais com deficiência de dados.

Abstract

The contributions from the use of geotechnical tools for the analysis of phenomena in the terrestrial surface are diverse for geographic studies. In addition to enabling a broader and more in-depth study of a particular area or process, these tools provide the basis for and provide knowledge and research in areas of data deficiencies or deficiencies. Therefore, due to the difficulties inherent in the collection and acquisition of data and physical elements, defined by the high cost, lack of infrastructure and resources, geotechnologies find a solution to meet the needs of this type of problem. In this sense, the research was structured through two main objectives, which went parallel and complement each other at the end. The first one was the comparison between the altimetric products from the PALSAR (lower resolution) and LiDAR (higher resolution) sensors in order to assess the quality of the results generated by the PALSAR sensor altimetry product in the identification of areas that are likely to occur landslides. The second objective was based on the application of the altimeter product of the PALSAR sensor for the Zoning of Risk Areas to Sludge in the Ribeirão dos Henriques (BHRH) and Ribeirão dos Palmares (BHRP) Hydrographic Basins located in the municipality of São João Nepomuceno- MG, this area has a lack of database. In general, it was found that despite the PALSAR product, not having the same accuracy and detail of the LiDAR, both presented several similarities. However, the evaluation of the homogeneity of data through the application of Coefficient of Determination (R²) and Pearson's Correlation Coefficient (r), as well as of the errors by Mean Absolute Error (MAE), Mean Relative Error (MRE) and the Root Mean Square Error (RMSE), demonstrated that both products show strong similarity. It should be noted that the Zoning of Risk Areas, generated from the Weighted Overlap method, between the Stability Index map and the Use, Coverage and Occupancy map of the surface, presented strong responses in the identification of risk areas to landslide in the Watershed Basins investigated, since, when analyzing the scars of past landslides in the area, a great part of them were evidenced on regions considered "High" or "Highest" Risk the occurrence of landslides. In view of the above, it was considered that the existing MOU in PALSAR / ALOS presents acceptable and convincing results to be applied in identifying areas susceptible to landslides, especially in places that do not have a satisfactory database. Finally, of the materials used, and of the methodology that was applied for the development of this study, it is believed that it is a model with several contributions for the identification of areas of risk to landslides.