Programa de Pós-Graduação em Geodinâmica e Geofísica
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Doctoral Thesis Geotecnologias de alta precisão no mapeamento de georisco a inundações frente às mudanças climáticas(2020-02-20) Araújo, Paulo Victor do Nascimento; Amaro, Venerando Eustáquio; ; ; Scudelari, Ada Cristina; ; Amaral, Ricardo Farias do; ; Lopes, Alexandre Bernadino; ; Silva, Paulo César Moura da;Flooding is the most common type of natural disaster worldwide and can have devastating consequences that affect the economy, environment and life dynamics of thousands of people. In addition, climate change and sea level rise have been accelerating and potentiating flood events, especially in coastal and riverine regions. However, are needy more studies of flood projections for the coming years, especially in local scale, with reliable geodetic references and which can guide mitigating actions. In this sense, the present doctoral thesis aimed to develop and apply methodology based on high vertical precision geotechnology in mapping flood geohazard in the front of climate change. This work was developed in two study areas in Brazil: (1) A cutout in the Piranhas-Açu estuary (study area 1), Rio Grande do Norte; and (2) a cut in the Uruguay River Basin (study area 2), Rio Grande do Sul. The choice of the two areas was because the regions has different types of floods (river flood x tidal flood) and with strong appeal scientific (social-economic-environmental). The methodology had as premise the use of high accuracy vertical ground control points, linked to the Brazilian Geodetic System and analyzed in a robust statistic for DEMs evaluation and calibration, developed and applied to the study area 1. Next, the methodology was employed for mapping the flooding geohazard in study area 2, a region under the influence of river flooding that comes with increasing trends of flood events. Finally, the methodology was applied to region 1 (region under the influence of tidal flooding). In this last stage, the current Intergovernmental Panel on Climate Change and Brazilian Institute of Geography and Statistics indicators on climate change and sea level rise for the year 2100 were taken as references. The results demonstrate high efficacy for the methodology of evaluation and calibration of DEM, obtaining evolutions in the reduction of the original DEM error by approximately 70%, as in the case of region 2 In addition, the mapping of floods, in both areas, demonstrate great robustness, validated with aerial photos and field records. The results of the flood hazard and risk mapping are alarming. The work proves that the annual fluviometric maximum level Uruguay River are in a positive trend and that the events of river floods will only increase. It was also found that approximately 118.26 km² of the Piranhas-Açú estuary is in an area of high risk and extremely high risk tidal flood, and in urgent need of mitigation measures. This thesis demonstrates that well applied techniques based on geotechnologies, such as remote sensing, GIS and high-precision geodesy, provide results that can be very effective for environmental management. The assessment of potentially floodable areas can help to reduce the negative impact of flooding events, supporting the land use planning process in areas exposed to the geo-hazard in focus.Master Thesis Análise geoambiental da plataforma continental Rasa Equatorial, por meio de sensoriamento remoto e dados sedimentológicos: parrachos de Rio do Fogo-RN, Brasil(Universidade Federal do Rio Grande do Norte, 2014-05-30) Araújo, Paulo Victor do Nascimento; Amaral, Ricardo Farias do; ; http://lattes.cnpq.br/5120081491389865; ; http://lattes.cnpq.br/4073388836947213; Amaro, Venerando Eustáquio; ; http://lattes.cnpq.br/4215328958233942; Tabosa, Werner Farkatt; ; http://lattes.cnpq.br/1313536081076361In the shallow continental shelf in Northeastern Rio Grande do Norte - Brazil, important underwater geomorphological features can be found 6km from the coastline. They are coral reefs, locally known as “parrachos”. The present study aims to characterize and analyze the geomorphological feature as well as the ones of the benthic surface, and the distribution of biogenic sediments found in parrachos at Rio do Fogo and associated shallow platforms, by using remote sensing products and in situ data collections. This was made possible due to sedimentological, bathymetric and geomorphological maps elaborated from composite bands of images from the satellite sensors ETM+/Landsat-7, OLI/Landsat-8, MS/GeoEye and PAN/WordView-1, and analysis of bottom sediments samples. These maps were analyzed, integrally interpreted and validated in fieldwork, thus permitting the generation of a new geomorphological zoning of the shallow shelf in study and a geoenvironmental map of the Parrachos in Rio do Fogo. The images used were subject to Digital Image Processing techniques. All obtained data and information were stored in a Geographic Information System (GIS) and can become available to the scientific community. This shallow platform has a carbonate bottom composed mostly by algae. Collected and analyzed sediment samples can be classified as biogenic carbonatic sands, as they are composed 75% by calcareous algae, according to the found samples. The most abundant classes are green algae, red algae, nonbiogenic sediments (mineral grains), ancient algae and molluscs. At the parrachos the following was mapped: Barreta Channel, intertidal reefs, submerged reefs, the spur and grooves, the pools, the sandy bank, the bank of algae, sea grass, submerged roads and Rio do Fogo Channel. This work presents new information about geomorphology and evolution in the study area, and will be guiding future decision making in the handling and environmental management of the region