Morfologia submersa do cânion Apodi-Mossoró baseado em dados in situ e geotecnologias multifontes

Abstract

The continental shelf adjacent to the city of Areia Branca in the state of Rio Grande do Norte has different forms of seabed, including the incised valleys of Apodi-Mossoró. The interest to characterize this feature was given by to host the facilities of the salt terminal of Areia Branca, known as Harbor Island of Areia Branca, which today constitutes the only way economically viable for send flow of large volumes of salt for chemical industries of country and indications that this area can provide on morphological variations and as wel as the possibility of spreading and shelter of quantities of hydrocarbons in the submerged canyon in case of accidental oil spills due to traffic of large ships for loading and unloading salt in the area. According to this fact the overall objective of this thesis was the detection of submerged bathymetry of the Canyon Apodi- Mossoró using data "in situ" and geotechnology multi-sources, including remote sensing tools for estimating bathymetry from Landsat satellite images with sensors ETM + (2014) and OLI (2015). The methodology included the use of nautical charts, bathymetric data, data interpolation by kriging and Natural Neighbor and integration of satellite images. Statistically there were differences between the two used interpolation methods, the Kriging revealed a positive linear association and overestimation of data Bathymetric situ with data from the Nautical Chart, and an inverse association and underestimation of data by the Natural Neighbor method, but both showed bathymetric maps with good visual contours. The results obtained from bathymetric maps indicated that the incised valleys Apodi-Mossoró suffered a constant remobilization of sediment, showing areas with shallower depths for the 2009 navigation for 2010, including the evolution basin of the Island Port and main navigation sections, thus requiring periodic dredging to avoid collision and stranding of ships. The acquisition, processing, integration and interpretation of satellite images correlated with the bottom morphology map allowed to confirm that the incised valleys Apodi-Mossoró has a form letter "J" at the exit to the north, and a shift eastwards due a submerged gradient quite evident on the map. Between the middle and inner platform was possible to observe different background shapes including flat bottom, isolated reefs and submerged field of dunes, the results also indicate that the incised valleys are formed by two channels, called shallow channel and deep channel, which have distinct morphological and sedimentological characteristics. And finally, it was observed that the use of data for bathymetry estimation Landsat has several advantages, in this study the ETM + sensor provided a better continuous twodimensional coverage that the OLI sensor, and the application of this method, easy to perform, can be of great value for regions where there are no bathymetric data or they are outdated, or even without the accuracy of nautical charts, maps such as those generated in this study are useful both for planning studies and environmental modeling and as well as for security to the navigation of large ships.