Técnicas de Ingeniería Cartográfica empleadas en el estudio de subsidencia y movimientos de ladera: principales características y análisis comparativo

Los movimientos de ladera y los procesos de subsidencia son fenómenos que afectan a la superficie terrestre produciendo modificaciones importantes sobre ella. Los cambios que originan se manifiestan como deformaciones superficiales cuyo estudio resulta de gran importancia en el campo de la Ingeniería Geología y la Geotecnia. En el presente trabajo se lleva a cabo una descripción de las técnicas de Ingeniería Cartográfica (técnicas topográficas, geodésicas, fotogramétricas y de teledetección) empleadas para cuantificar las deformaciones causadas por movimientos de ladera y subsidencia terrestre, estableciendo sus principales características y llevando a cabo un análisis comparativo de las mismas.

Enquadramento cartográfico do Complexo de Granja (NW Ceará, Brasil) e avaliação de sistemas de referenciação geográfica

Este estudo destaca os benefícios da análise metódica da cartografia de base que suporta a produção de Cartografia Geológica. Em certas regiões, as cartas base publicadas estão ainda associadas a redes geodésicas clássicas e, com frequência, são introduzidos erros quando se desconsideram parâmetros essenciais como a Projecção Cartográfica e o Datum Geodésico. Com o uso sistemático dos dispositivos de GPS e dos Sistemas de Informação Geográfica para a elaboração das cartas geológicas, é imprescindível o conhecimento prévio do Sistema de Coordenadas ao qual devem estar ajustados os dados geo-espaciais. Neste estudo de caso, as diferenças e os erros associados à aquisição de coordenadas entre os Data geocêntricos WGS84 e SIRGAS2000 são residuais, atendendo aos parâmetros das cartas base, à região do globo, o campo de acção e a escala, minimizando assim a propagação de erros de posicionamento e georreferenciação subsequentes.

Contribuição da Geodésia ao monitoramento costeiro do Litoral Setentrional do Rio Grande do Norte, área de influência da indústria petrolífera

The general objective of this thesis has been seasonal monitoring (quarterly time scale) of coastal and estuarine areas of a section of the Northern Coast of Rio Grande do Norte, Brazil, environmentally sensitive and with intense sediment erosion in the oil activities to underpin the implementation of projects for containment of erosion and mitigate the impacts of coastal dynamics. In order to achieve the general objective, the work was done systematically in three stages which consisted the specific objectives. The first stage was the implementation of geodetic reference infrastructure for carrying out the geodetic survey of the study area. This process included the implementation of RGLS (Northern Coast of the RN GPS Network), consisting of stations with geodetic coordinates and orthometric heights of precision; positioning of Benchmarks and evaluation of the gravimetric geoid available, for use in GPS altimetry of precision; and development of software for GPS altimetry of precision. The second stage was the development and improvement of methodologies for collection, processing, representation, integration and analysis of CoastLine (CL) and Digital Elevation Models (DEM) obtained by geodetic positioning techniques. As part of this stage have been made since, the choice of equipment and positioning methods to be used, depending on the required precision and structure implanted, and the definition of the LC indicator and of the geodesic references best suited, to coastal monitoring of precision. The third step was the seasonal geodesic monitoring of the study area. It was defined the execution times of the geodetic surveys by analyzing the pattern of sediment dynamics of the study area; the performing of surveys in order to calculate and locate areas and volumes of erosion and accretion (sandy and volumetric sedimentary balance) occurred on CL and on the beaches and islands surfaces throughout the year, and study of correlations between the measured variations (in area and volume) between each survey and the action of the coastal dynamic agents. The results allowed an integrated study of spatial and temporal interrelationships of the causes and consequences of intensive coastal processes operating in the area, especially to the measurement of variability of erosion, transport, balance and supply sedimentary over the annual cycle of construction and destruction of beaches. In the analysis of the results, it was possible to identify the causes and consequences of severe coastal erosion occurred on beaches exposed, to analyze the recovery of beaches and the accretion occurring in tidal inlets and estuaries. From the optics of seasonal variations in the CL, human interventions to erosion contention have been proposed with the aim of restoring the previous situation of the beaches in the process of erosion.

Monitoramento da morfologia costeira em setores da bacia potiguar sob influência da indústria petrolífera utilizando geodésia de alta precisão e laser escâner terrestre

The objective of this Doctoral Thesis was monitoring, in trimestral scale, the coastal morphology of the Northeastern coast sections of Rio Grande do Norte State, in Brazil, which is an area of Potiguar Basin influenced by the oil industry activities. The studied sections compose coastal areas with intense sedimentary erosion and high environmental sensitivity to the oil spill. In order to achieve the general objective of this study, the work has been systematized in four steps. The first one refers to the evaluation of the geomorphological data acquisition methodologies used on Digital Elevation Model (DEM) of sandy beaches. The data has been obtained from Soledade beach, located on the Northeastern coast of Rio Grande Norte. The second step has been centered on the increasing of the reference geodetic infrastructure to accomplish the geodetic survey of the studied area by implanting a station in Corta Cachorro Barrier Island and by conducting monitoring geodetic surveys to understand the beach system based on the Coastline (CL) and on DEM multitemporal analysis. The third phase has been related to the usage of the methodology developed by Santos; Amaro (2011) and Santos et al. (2012) for the surveying, processing, representation, integration and analysis of Coastlines from sandy coast, which have been obtained through geodetic techniques of positioning, morphological change analysis and sediment transport. The fourth stage represents the innovation of surveys in coastal environment by using the Terrestrial Laser Scanning (TLS), based on Light Detection and Ranging (LiDAR), to evaluate a highly eroded section on Soledade beach where the oil industry structures are located. The evaluation has been achieved through high-precision DEM and accuracy during the modeling of the coast morphology changes. The result analysis of the integrated study about the spatial and temporal interrelations of the intense coastal processes in areas of building cycles and destruction of beaches has allowed identifying the causes and consequences of the intense coastal erosion in exposed beach sections and in barrier islands