Avaliação da retração no curto prazo da falésia marinha ativa da Barreira do Inferno com o uso do Laser Escâner Terrestre

Abstract

This research aims a short-term multi-temporal evaluation of the seacliff retreat of the Barreiras Formation, in the Barreira do Inferno Launch Center (CLBI, in Portuguese) located in the eastern coast of Rio Grande do Norte (RN), Brazil. The studies were conducted between August 2016 and February 2017 through a Terrestrial Laser Scanning (TLS), which is equipment that utilizes a pulsed laser to map seacliffs face. The first phase of the study used the point cloud generated on August 21, 2016, for the construction of 10 Digital Elevation Model (DEM) via four different softwares for selecting the interpolation method that best represents the studied surface. The second phase was the description of the seacliff according to its main erosive cause through 30 transversal seacliff face profiles obtained through the DEM generated in the previous phase. It led to a subdivision of the seacliff in 5 segments according to its description. The evaluation and quantification of the net erosion and the retreat rate were conducted through comparing the DEMs with the transversal profiles generated. The results expressed that the seacliff had a retreat of approximately 6 centimeters with a net erosion of 333 m³ during the study period. It was also observed the importance of evaluating the reliability of the point cloud because of the presence of blanks due to the shading during the data collection, which may cause significant errors. The evaluation of this seacliff was relevant not only because it was the first to be done through TLS in this type of formation, but also because it represents a new way for understanding the coast dynamic.