The use of tsunami models for applications of 'now-casting', which is the prediction of the present and near future behavior, has limited exploration, and could potentially be of significant usefulness. Tsunamis are most often caused by earthquakes in subduction zones, which generates coupled uplift and subsidence, and displaces the water column. The behavior of the fault failure is difficult to describe in the short term, often requiring seismic waveform inversion, which takes a length of time on the order of weeks to months to properly model, and is much too late for any use in a now-casting sense. To expedite this length of time, a series of source models are created with variable fault geometry behaviors, using fault parameters from Northern Oceanic and Atmospheric Administration's Short-term Inundation and Forecasting of Tsunamis (SIFT) database, in order to model a series of potential tsunami behaviors using the numerical modelling package, GeoClaw. The implementation of modeling could identify areas of interest for further study that are sensitive to fault failure geometry. Initial results show that by varying the geometry of sub-faults of a given earthquake, the resulting tsunami models behave fairly differently with different wave dispersion behavior, both in pattern and magnitude. While there are shortcomings of the potential geometries the code created in this study, and there are significant improvements that can be made, this study provides a good starting point into now-casting of tsunami models, with future iterations likely involving statistical probability in the fault failure geometries. / Master of Science / Short term modeling of tsunamis generated by earthquakes is poorly explored. If an earthquake causes movement in a fault located underwater, and this movement will then cause the water column above it to be displaced. Tsunami models are sensitive to how the fault moves, and an accurate representation of this movement often takes much more time that the duration of a tsunami. This lengthy process is ineffective for short term modeling. This study instead estimates several possible scenarios of how the fault will behave, and model each of them. This will show how different locations of interest are sensitive to different geometries of fault failure. Initial results show that by varying this geometry, the tsunami wave behaves very differently, and will cause different amounts of run-up in the same location depending on which particular geometry is modeled. The automation of distinctly different earthquake sources serve as a good starting point for future work to be conducted to generate more accurate models.

O objetivo desta tese é estudar a dinâmica de mesoescala do sistema de correntes de contorno oeste ao largo da costa leste brasileira entre 10o -20o S. Esta é a área em que a Corrente Sul Equatorial (CSE) se bifurca, no escopo da circulação de larga escala forcada pelo vento associado ao giro subtropical do Atlântico Sul. Este sistema de bifurcação, somado à circulacao equatorial, tem uma estrutura tri-dimensional complexa que implica na formação de diversas correntes de contorno oeste (CCOs) que fluem ao largo da costa brasileira. Este sistema de CCOs tem sido reconhecido na literatura como de extrema importância nos últimos anos, por estar embebido nos padrões de larga escala da Célula de Revolvimento Meridional no Atlântico Sul. Transportes de calor e volume entre hemisférios em diferentes profundidades são parcialmente controlados pela média de longo termo da atividade de mesoescala na região supracitada, seja esta gerada localmente ou forçada remotamente. Esta tese objetiva estudar a dinâmica do oceano superior nesta região em dois capítulos independentes. Cada um destes capítulos são auto-suficientes em seu conteúdo, descrevendo suas hipóteses, metodologia, resultados, discussões e implicações. O conteúdo de cada um destes capítulos é sumarizado nos parágrafos seguintes. A Corrente do Brasil (CB) se origina com a chegada e bifurcação da CSE em superfície, entre 10-20o . A CB é uma CCO centrada em superfície e transporta águas quentes e salinas em direção ao pólo sul. Estudos climatológicos prévios descrevem a bifurcação da CSE como um fenômeno estratificado vertical e horizontalmente, e que o ramo sul da CSE dá origem a CB - uma corrente de contorno oeste fraca e rasa. A origem da CB é atualmente um dos aspectos menos explorados da circulação regional e sua atividade de mesoescala na parte oeste do giro subtropical do Atlântico Sul. O Capítulo 1 deste trabalho objetiva preencher esta lacuna de conhecimento descritivo na porção entre 10o-20o S ao largo da costa brasileira. A análise de três cruzeiros quase-sinóticos recentes em conjunto com padrões inferidos por altimetria e modelos de circulação global, confronta a descrição da CB como uma corrente de contorno oeste contínua. De acordo com nossas análises, o sinal da bifurcação da CSE próximo à costa não é claro, e os campos de velocidade são dominados por estruturas vorticais de mesoescala. Anticiclones recorrentes que aparentam estar associados ao meandramento da CB, nos conduzem a estabelecer um cenário de escoamento fortemente influenciado pela topografia e possivelmente instável. Diante desde cenário, sugerimos que a CB se caracteriza por um escoamento dominado por vórtices ao norte do paralelo de 20o S. O Capítulo 2 parte do pressuposto enunciado no Capítulo 1 e objetiva estudar os papéis do cisalhamento vertical e da topografia na formação dos vórtices observados na região de origem da CB. Apresentamos simulações numéricas de estudo de processo que mostram que as principais feições realísticas de mesoescala nas imediações da origem da CB podem ser reproduzidas com sucesso a partir da interação dinâmica entre versões parametrizadas do escoamento médio de dois jatos de contorno oeste e fluindo em sentido oposto (CB e Sub-corrente Norte do Brasil - SNB) e a topografia local, sem influência de dinâmica remota ou forçantes atmosféricas. Três extensos anticiclones reportados no Capítulo 1 são reproduzidos e apresentam um comportamento estacionário durante um ano de simulação. Dois experimentos de sensitividade adicionais são conduzidos. Quando a SNB é suprimida do contexto físico, a interação entre CB e topografia não é suficiente para reproduzir tais feições anticiclônicas, e em geral, o padrão obtido exibe pouca semelhança aos dados observacionais. Quando uma topografia idealizada, livre de bancos e montes submarinos é adotada, a interação CB-SNB é também insuficiente para produzir as estruturas realísticas de mesoescala. Nossa análise sugere que vórtices anticlônicos de borda de promontório ocorrem nos níveis verticais da SNB (cerca de 400 m) e que estes estão forçando o aparecimento de anticiclones em superfície (CB) cerca de 10 dias depois. Esta tese tem estrutura baseada em dois artigos científicos pré-existentes, ambos de autoria do presente aluno, com co-autoria de seu orientador, co-orientador e colegas. O Capítulo 1 destina-se aos resultados de um artigo publicado no periódico científico denominado Geophysical Research Letters [Soutelino et al., 2011] e o Capítulo 2 refere-se a um artigo atualmente submetido ao periódico científico denominado Continental Shelf Research [Soutelino et al., subm]. O conteúdo de ambos os capítulos estão expandidos em relação as versões originais para permitir maior nível de detalhamento das diversas partes que compõem o trabalho. Mais detalhes relativos às técnicas metodologicas são apresentados, bem como um maior numero de gráficos, buscando maximizar a clareza do documento. O Capítulo 3 compila e sumariza os resultados oriundos de ambos os artigos científicos, e consequentemente desta tese, finalizando com sugestões para trabalhos futuros. / This dissertation addresses the mesoscale dynamics of the western boundary current system off Brazilian coast easternmost portion (10o -20o S). This is the area where the South Equatorial Current (SEC) of the Atlantic Ocean bifurcates, in the scope of the large scale wind driven subtropical gyre. This bifurcation, summed to the Equatorial circulation, has a complex tri-dimensional structure that leads to the formation of several different western boundary currents (WBCs) flowing in different directions and in different depths off the entire Brazilian coast. This system have been recognized to have major scientific importance in the last few years, because it is embedded in the South Atlantic Meridional Overturning Circulation (SAMOC) large scale pathways. Inter-hemisphere volume and heat net transports in different depths are partly controlled by the time-averaged effect of mesoscale features occurring in the region cited above, being these generated locally or remotely. This dissertation intends to address the upper ocean regional dynamics of this area in two self-contained chapters. Each of these chapters can stand alone, independently describing the problem, the methods, the results, and their implications. The contents of each chapter are summarized in the next paragraphs. The Brazil Current (BC) originates with the arrival and bifurcation of the southernmost branch of the South Equatorial Current (sSEC) at the surface between 10-20o. The BC is a surface-cored feature and it transports warm and salty waters poleward. Previous climatological studies showed a stratified sSEC bifurcation and that the resulting southern branch formed a shallow BC - a weak western boundary current. The site of origin of the BC is currently one of the less explored aspects of regional circulation and mesoscale activity in the South Atlantic Subtropical gyre westernmost portion. Chapter 1 of this work aims to fill this gap in the 10o -20o S zone off the Brazilian coast. The analysis of three recent synoptic surveys and global model outputs challenge the description of a continuous BC. According to our analysis, The sSEC bifurcation signal near the continental margin is unclear, and the velocity fields are dominated by mesoscale eddies. Recurrent anticyclones that seem to be related to the meandering BC leads us to construct a picture of a flow strongly influenced by topography and probably very unstable. Given this new emerging scenario, we hypothesize that the Brazil Current is eddy-dominated to the north of 20o S. Chapter 2 of this dissertation assumes the hypothesis formulated in Chapter 1 to be true, and studies the roles of vertical shear and topography on the eddy formation near the site of origin of the BC. We present numerical simulations that show that the main realistic mesoscale features in the eddy-rich vicinities of the BC site of origin can be successfully modeled through the dynamical interaction between parameterized versions of two opposing mean western boundary currents (BC and North Brazil Undercurrent - NBUC) and local topography, with no influence of remote dynamics or atmospheric forcing. Three large BC-related anticyclones described in Chapter 1 are reproduced and present a steady behavior during one year run. Two additional sensitivity experiments are performed. When NBUC is removed from the physical context, BC interaction with topography is not sufficient to generate such eddies, and the overall pattern shows considerably less resemblance with real data. When an idealized flat-bottom and no-banks topography is considered, BC-NBUC interaction is also not capable of developing realistic mesoscale structures. Our analyses suggest that leeward anticyclonic eddy generation mechanism is occurring at NBUC vertical levels (around 400 m) at the lee of bathymetric promontories and that this is driving the appearance of these eddies in the surface levels (BC domain) with a 10 days time lag. This dissertation structure is based on two existing scientific papers, both having the current PhD candidate as the first author, and co-authorship of his advisor, co-advisor and colleagues. Chapter 1 refers to the results of an article published at the Geophysical Research Letters scientific journal [Soutelino et al., 2011] and the Chapter 2 refers to an article currently submitted to Continental Shelf Research [Soutelino et al., subm]. The contents of both Chapter 1 and Chapter 2 are expanded in respect to the publication versions. More details regarding the applied methods and additional graphics and computations are shown. Finally, Chapter 3 ends the dissertation with final remarks.

O objetivo desta tese é estudar a dinâmica de mesoescala do sistema de correntes de contorno oeste ao largo da costa leste brasileira entre 10o -20o S. Esta é a área em que a Corrente Sul Equatorial (CSE) se bifurca, no escopo da circulação de larga escala forcada pelo vento associado ao giro subtropical do Atlântico Sul. Este sistema de bifurcação, somado à circulacao equatorial, tem uma estrutura tri-dimensional complexa que implica na formação de diversas correntes de contorno oeste (CCOs) que fluem ao largo da costa brasileira. Este sistema de CCOs tem sido reconhecido na literatura como de extrema importância nos últimos anos, por estar embebido nos padrões de larga escala da Célula de Revolvimento Meridional no Atlântico Sul. Transportes de calor e volume entre hemisférios em diferentes profundidades são parcialmente controlados pela média de longo termo da atividade de mesoescala na região supracitada, seja esta gerada localmente ou forçada remotamente. Esta tese objetiva estudar a dinâmica do oceano superior nesta região em dois capítulos independentes. Cada um destes capítulos são auto-suficientes em seu conteúdo, descrevendo suas hipóteses, metodologia, resultados, discussões e implicações. O conteúdo de cada um destes capítulos é sumarizado nos parágrafos seguintes. A Corrente do Brasil (CB) se origina com a chegada e bifurcação da CSE em superfície, entre 10-20o . A CB é uma CCO centrada em superfície e transporta águas quentes e salinas em direção ao pólo sul. Estudos climatológicos prévios descrevem a bifurcação da CSE como um fenômeno estratificado vertical e horizontalmente, e que o ramo sul da CSE dá origem a CB - uma corrente de contorno oeste fraca e rasa. A origem da CB é atualmente um dos aspectos menos explorados da circulação regional e sua atividade de mesoescala na parte oeste do giro subtropical do Atlântico Sul. O Capítulo 1 deste trabalho objetiva preencher esta lacuna de conhecimento descritivo na porção entre 10o-20o S ao largo da costa brasileira. A análise de três cruzeiros quase-sinóticos recentes em conjunto com padrões inferidos por altimetria e modelos de circulação global, confronta a descrição da CB como uma corrente de contorno oeste contínua. De acordo com nossas análises, o sinal da bifurcação da CSE próximo à costa não é claro, e os campos de velocidade são dominados por estruturas vorticais de mesoescala. Anticiclones recorrentes que aparentam estar associados ao meandramento da CB, nos conduzem a estabelecer um cenário de escoamento fortemente influenciado pela topografia e possivelmente instável. Diante desde cenário, sugerimos que a CB se caracteriza por um escoamento dominado por vórtices ao norte do paralelo de 20o S. O Capítulo 2 parte do pressuposto enunciado no Capítulo 1 e objetiva estudar os papéis do cisalhamento vertical e da topografia na formação dos vórtices observados na região de origem da CB. Apresentamos simulações numéricas de estudo de processo que mostram que as principais feições realísticas de mesoescala nas imediações da origem da CB podem ser reproduzidas com sucesso a partir da interação dinâmica entre versões parametrizadas do escoamento médio de dois jatos de contorno oeste e fluindo em sentido oposto (CB e Sub-corrente Norte do Brasil - SNB) e a topografia local, sem influência de dinâmica remota ou forçantes atmosféricas. Três extensos anticiclones reportados no Capítulo 1 são reproduzidos e apresentam um comportamento estacionário durante um ano de simulação. Dois experimentos de sensitividade adicionais são conduzidos. Quando a SNB é suprimida do contexto físico, a interação entre CB e topografia não é suficiente para reproduzir tais feições anticiclônicas, e em geral, o padrão obtido exibe pouca semelhança aos dados observacionais. Quando uma topografia idealizada, livre de bancos e montes submarinos é adotada, a interação CB-SNB é também insuficiente para produzir as estruturas realísticas de mesoescala. Nossa análise sugere que vórtices anticlônicos de borda de promontório ocorrem nos níveis verticais da SNB (cerca de 400 m) e que estes estão forçando o aparecimento de anticiclones em superfície (CB) cerca de 10 dias depois. Esta tese tem estrutura baseada em dois artigos científicos pré-existentes, ambos de autoria do presente aluno, com co-autoria de seu orientador, co-orientador e colegas. O Capítulo 1 destina-se aos resultados de um artigo publicado no periódico científico denominado Geophysical Research Letters [Soutelino et al., 2011] e o Capítulo 2 refere-se a um artigo atualmente submetido ao periódico científico denominado Continental Shelf Research [Soutelino et al., subm]. O conteúdo de ambos os capítulos estão expandidos em relação as versões originais para permitir maior nível de detalhamento das diversas partes que compõem o trabalho. Mais detalhes relativos às técnicas metodologicas são apresentados, bem como um maior numero de gráficos, buscando maximizar a clareza do documento. O Capítulo 3 compila e sumariza os resultados oriundos de ambos os artigos científicos, e consequentemente desta tese, finalizando com sugestões para trabalhos futuros. / This dissertation addresses the mesoscale dynamics of the western boundary current system off Brazilian coast easternmost portion (10o -20o S). This is the area where the South Equatorial Current (SEC) of the Atlantic Ocean bifurcates, in the scope of the large scale wind driven subtropical gyre. This bifurcation, summed to the Equatorial circulation, has a complex tri-dimensional structure that leads to the formation of several different western boundary currents (WBCs) flowing in different directions and in different depths off the entire Brazilian coast. This system have been recognized to have major scientific importance in the last few years, because it is embedded in the South Atlantic Meridional Overturning Circulation (SAMOC) large scale pathways. Inter-hemisphere volume and heat net transports in different depths are partly controlled by the time-averaged effect of mesoscale features occurring in the region cited above, being these generated locally or remotely. This dissertation intends to address the upper ocean regional dynamics of this area in two self-contained chapters. Each of these chapters can stand alone, independently describing the problem, the methods, the results, and their implications. The contents of each chapter are summarized in the next paragraphs. The Brazil Current (BC) originates with the arrival and bifurcation of the southernmost branch of the South Equatorial Current (sSEC) at the surface between 10-20o. The BC is a surface-cored feature and it transports warm and salty waters poleward. Previous climatological studies showed a stratified sSEC bifurcation and that the resulting southern branch formed a shallow BC - a weak western boundary current. The site of origin of the BC is currently one of the less explored aspects of regional circulation and mesoscale activity in the South Atlantic Subtropical gyre westernmost portion. Chapter 1 of this work aims to fill this gap in the 10o -20o S zone off the Brazilian coast. The analysis of three recent synoptic surveys and global model outputs challenge the description of a continuous BC. According to our analysis, The sSEC bifurcation signal near the continental margin is unclear, and the velocity fields are dominated by mesoscale eddies. Recurrent anticyclones that seem to be related to the meandering BC leads us to construct a picture of a flow strongly influenced by topography and probably very unstable. Given this new emerging scenario, we hypothesize that the Brazil Current is eddy-dominated to the north of 20o S. Chapter 2 of this dissertation assumes the hypothesis formulated in Chapter 1 to be true, and studies the roles of vertical shear and topography on the eddy formation near the site of origin of the BC. We present numerical simulations that show that the main realistic mesoscale features in the eddy-rich vicinities of the BC site of origin can be successfully modeled through the dynamical interaction between parameterized versions of two opposing mean western boundary currents (BC and North Brazil Undercurrent - NBUC) and local topography, with no influence of remote dynamics or atmospheric forcing. Three large BC-related anticyclones described in Chapter 1 are reproduced and present a steady behavior during one year run. Two additional sensitivity experiments are performed. When NBUC is removed from the physical context, BC interaction with topography is not sufficient to generate such eddies, and the overall pattern shows considerably less resemblance with real data. When an idealized flat-bottom and no-banks topography is considered, BC-NBUC interaction is also not capable of developing realistic mesoscale structures. Our analyses suggest that leeward anticyclonic eddy generation mechanism is occurring at NBUC vertical levels (around 400 m) at the lee of bathymetric promontories and that this is driving the appearance of these eddies in the surface levels (BC domain) with a 10 days time lag. This dissertation structure is based on two existing scientific papers, both having the current PhD candidate as the first author, and co-authorship of his advisor, co-advisor and colleagues. Chapter 1 refers to the results of an article published at the Geophysical Research Letters scientific journal [Soutelino et al., 2011] and the Chapter 2 refers to an article currently submitted to Continental Shelf Research [Soutelino et al., subm]. The contents of both Chapter 1 and Chapter 2 are expanded in respect to the publication versions. More details regarding the applied methods and additional graphics and computations are shown. Finally, Chapter 3 ends the dissertation with final remarks.

<p>This thesis uses results of systematic numerical models to argue that externally inactive salt structures, which are potential targets for radioactive waste disposal, might be internally active due to the presence of dense layers or blocks within a salt layer.</p><p>The three papers that support this thesis use the Gorleben salt diapir (NW Germany), which was targeted as a future final repository for high-grade radioactive waste, as a general guideline.</p><p>The first two papers present systematic studies of the parameters that control the development of a salt diapir and how it entrains a dense anhydrite layer. Results from these numerical models show that the entrainment of a dense anhydrite layer within a salt diapir depends on four parameters: sedimentation rate, viscosity of salt, perturbation width and the stratigraphic location of the dense layer. The combined effect of these four parameters, which has a direct impact on the rate of salt supply (volume/area of the salt that is supplied to the diapir with time), shape a diapir and the mode of entrainment. Salt diapirs down-built with sedimentary units of high viscosity can potentially grow with an embedded anhydrite layer and deplete their source layer (salt supply ceases). However, when salt supply decreases dramatically or ceases entirely, the entrained anhydrite layer/segments start to sink within the diapir. In inactive diapirs, sinking of the entrained anhydrite layer is inevitable and strongly depends on the rheology of the salt, which is in direct contact with the anhydrite layer. During the post-depositional stage, if the effective viscosity of salt falls below the threshold value of around 10¹⁸-10¹⁹ Pa s, the mobility of anhydrite blocks might influence any repository within the diapir. However, the internal deformation of the salt diapir by the descending blocks decreases with increase in effective viscosity of salt.</p><p>The results presented in this thesis suggest that it is highly likely that salt structures where dense and viscous layer/blocks are present undergo an internal deformation processes when these dense blocks start sinking within the diapir. Depending on size and orientation of these blocks, deformation pattern is significantly different within the diapir. Furthermore, model results applied to the Gorleben diapir show that the rate of descent of the entrained anhydrite blocks differs on different sides of the diapir. This suggests that if the anhydrite blocks descent within the Gorleben diapir, they initiate an asymmetric internal flow within it.</p>

Water managers must balance the need for clean and safe drinking water with ever-increasing amounts of waste-water. A technique for treating and storing surface water called “managed aquifer recharge” (MAR) is frequently used to help maintain this balance. When MAR is used to produce drinking water, water managers must ensure that disease-causing microbial contaminants are removed from the water prior to its distribution. This thesis examined the processes responsible for removing a specific class of microbial contaminants called “enteric viruses” during MAR. Viruses are naturally removed in groundwater through adsorption and inactivation mechanisms. This thesis investigated how these virus removal mechanisms were affected by ionic strength (IS), dissolved organic carbon (DOC), and the age of the sand used in a MAR infiltration basin. This was done using batch and flow-through column experiments designed to mimic conditions characteristic of a basin infiltration MAR scheme in Uppsala, Sweden. Bacteriophage MS2 was used as a proxy for enteric viruses. All of the experiments were conducted at 4°C. Experimental data were modeled to describe the fate and transport of viruses in the infiltrated groundwater. Conventional least-squares optimization and generalized likelihood uncertainty estimation (GLUE) were compared as model fitting-approaches in order to determine how data uncertainty affects parameter estimates and model predictions. Results showed that the sand used in the infiltration basins accumulates adsorbed organic matter as it is exposed to infiltrating surface waters. This reduced the amount of MS2 that was removed due to adsorption and inactivation. Results from GLUE indicated that MS2 is more likely to inactivate in a time-dependent manner when in the presence of sand with high concentrations of organic matter. Both model fitting techniques indicated that virus attachment rates were significantly lower for sand with high organic carbon content. Neither methodology was capable of adequately capturing the kinetics of virus adsorption. Uncertainties in the experimental data had a large effect on the conclusions that could be drawn from fitted models. This study showed that the presence of natural organic matter reduces the value of the infiltration basin as a microbial barrier.

Les phénomènes d’instabilité générés par les séismes dans les pentes représentent un risque naturel majeur à l’échelle mondiale. Ce risque a, de plus, tendance à croître du fait d’une urbanisation croissante dans des zones à fort aléa, comme en témoignent de nombreux évènements catastrophique à travers le passé. Pour garantir la sécurité des personnes et des biens face à ce type d’aléa, il faut améliorer les prédictions des déplacements générés par les séismes dans les pentes.Les premiers travaux scientifiques visant à corréler les caractéristiques des instabilités dans les pentes aux paramètres sismiques sont de nature empirique et remontent aux années 1980. Ces méthodes ne permettent pas d’expliquer tous les mouvements de terrain observés à travers le monde, notamment lorsque les effets de site modifient sensiblement la distribution des mouvements dans les pentes et génèrent des déplacements plus grands ou plus petits que ceux prédits par les lois empiriques qui négligent les effets de site.La première partie de cette thèse présente une nouvelle base de données mondiale de 277 glissements de terrain d’origine sismique ou non. L’analyse statistique conduite sur les données de cette base a montré que la forme géométrique moyenne des glissements de terrain reste stable lorsque le volume des instabilités augmente.La deuxième partie de la thèse est dédiée à l’analyse de la stabilité du glissement de terrain de Diezma (Espagne) au moyen de trois méthodes : la Méthode de NEWMARK (1965) basée sur le principe de l’équilibre limite en 2D qui suppose des conditions elasto-parfaitement-plastiques ; l’analyse par différences finies dans le domaine temporel avec le code FLAC en 2D et en 3D qui suppose des conditions visco-elasto-parfaitement-plastiques ; et l’analyse par recombinaison modale dans le domaine fréquentiel avec le code CESAR-LCPC en 2D et en 3D qui suppose des conditions visco-élastiques.Situé dans une région sismiquement active, le glissement de terrain de Diezma est susceptible d’être affecté par des séismes. Une analyse des déplacements induits dans ce versant par onze signaux sismiques différents a été menée dans l’objectif d’établir des corrélations entre les paramètres macro-sismiques des scenarios sismiques appliqués et les déformations calculées par les trois méthodes.Les résultats montrent des différences marquées à la fois qualitatives et quantitatives. Les conclusions principales sont : (a) Les déplacements obtenus par les trois méthodes ont des ordres de grandeur différents et peuvent donc conduire à une surestimation ou à une sous-estimation des déplacements ; (b) Les deux méthodes numériques montrent que les déplacements sont fortement conditionnés par la géométrie des modèles ; seule la méthode par différences finies fait apparaître une réponse en termes de déplacements qui dépend du scénario sismique considéré; (c) Les résultats des simulations2D et 3D ne sont pas comparables ; des analyses complémentaires doivent encore être menées pour guider l’utilisateur dans le choix de la méthode la plus appropriée; (d) La Méthode de NEWMARK (1965), dont l’utilisation reste très répandue de nos jours, est tout à fait appropriée à l’étude de cas simples mais elle peut se révéler inexacte lorsque la structure géologique / topographique du versant conduit à un fort effet de site car ce dernier n’est pas pris en compte par cette méthode / Seismically induced slope deformation is a worldwide common phenomenon that poses an increasing and considerable threat to fast expanding urbanization, and a great number of catastrophic events throughout the past attest thereof. For this reason, displacement predictions allowing for proper slope surveillance became a major concern.Early attempts to relate slope failures to seismic parameters are of empirical nature and date back to the 1980s. Although having proven stable, these relations are frequently disturbed by site effects causing outliers in terms of smaller or greater displacements than expected.The first part of this thesis presents a newly build chronological database of 277 globally distributed seismically and non-seismically induced landslides. A comprehensive statistical analysis was conducted on the data of this database with the main result that – statistically seen – the average geometrical shapes of landslides differ only proportionally.The second part of the thesis is dedicated to a comparative slope stability analysis of the Diezma Landslide (Spain) by means of three methods: the limit-equilibrium based NEWMARK-Method (1965) in 2D under elasto-perfectly-plastic conditions; finite-difference analysis in the time domain with the code FLAC in 2D and 3D under visco-elasto-perfectly-plastic conditions; and modal recombination analysis in the frequency domain with the finite-element code CESAR-LCPC in 2D and 3D under visco-elastic conditions.Located in a seismically active region, the Diezma Landslide is likely to be affected by earthquakes and was therefore considered as a suitable model case. A broad analysis of expected displacements was conducted using eleven strong-motion seismic scenarios. Moreover, the thesis searches for potential relations between macro-seismic parameters of the applied earthquake scenarios and the predicted deformations obtained from the three methods.It appeared that – due to the functionality of the methods – results differ quantitatively as well as qualitatively, and so does their suitability. Major findings are: (a) Results from the three methods are of different orders of magnitude and, thus, can easily lead to over- or under-estimations of displacements; (b) Both numerical methods reveal a strong influence of the model-geometry on the predicted displacements, whereas a scenario-dependent slope behavior manifested itself only within the finite difference analysis; (c) The switch from 2D to 3D does not necessarily result in a similar performance in each dimension and results must be critically judged before further use; (d) The NEWMARK-Method (1965) has proven itself once more to be appropriate for first slope assessments but not for sophisticated evaluations of ground response to seismic shaking

A modelagem matemática do escoamento em duas dimensões é uma ferramenta importante para a pesquisa hidráulica e o desenvolvimento de projetos. Nesta dissertação é apresentado um estudo da hidrodinâmica bidimensional através de modelos matemáticos, sendo inicialmente introduzidas as equações básicas da mecânica dos fluídos que regem o movimento em duas direções. Em seguida são discutidas alguns modelos apresentados pela bibliografia, de onde podem ser obtidas valiosas informações sobre a técnica de modelação. Após a apresentação do método das diferenças finitas, um modelo matemático implícito é proposto para a aplicação em estudos bidimensionais onde é necessário o cálculo detalhado do campo de velocidades, evitando-se as restrições devido a estabilidade e acuracidade do método de diferenças. Como conclusão, são apresentados alguns exemplos de aplicação e comparações dos resultados com outros modelos. / Numerical modelling of two-dimensional flow is very important as a tool for hydraulic research and design. This work starts with a review of basic fluid mechanics equations of the wave motion in two-directions. Then some aspects of models proposed by several authors are discussed. The Finite Diference method is presented and na implicit model is proposed for aplication in detailed studies. The stability and acuraccy are investigated to recognize the range of model aplication. Some practical examples and comparisons are shown to test model capabilities.

O termo macro-rugosidade é empregado para caracterizar os elementos contínuos ou esparsos de formas diversas, que são aplicados artificialmente no fundo e paredes dos condutos hidráulicos, em oposição à rugosidade de grão, relacionada às asperezas das paredes destes condutos. Neste trabalho apresenta-se o estudo teórico-experimental do comportamento do escoamento livre com a presença de macro-rugosidade constituída de elementos prismáticos de seção transversal retangular, denominados travessões, que encontram aplicações práticas na estabilização de leitos e regularização de canais para navegação. O emprego da macro-rugosidade resulta na ocorrência de maiores perdas de energia quando as profundidades são pequenas e na redução progressiva deste efeito à medida que a lâmina d\'água se eleva. O estudo teórico compreende o tratamento dado pela literatura ao problema da resistência ao escoamento em canais, desenvolvido a partir da integração da tradicional lei logarítmica para o para o perfil bidimensional de velocidades. Também foi abordado o modelo de distribuição probabilística de velocidades de CHIU, baseado na maximização da entropia. Estudos específicos sobre macro-rugosidade de fundo, desenvolvidos a partir da década de 1960, foram pesquisados para orientação dos estudos experimentais desenvolvidos, notadamente os trabalhos de MORRIS & WIGGERT, SAYRE & ALBERTSON e KNIGHT & MACDONALD. Ensaios experimentais foram desenvolvidos em canal de laboratório para acaracterização das perdas de carga dos travessões de fundo, em diferentes condições de profundidade e espaçamento longitudinal. Nestes ensaios desenvolveu-se uma técnica para medição das perdas de energia e cálculo das tensões de atrito em escoamentos permanentes e gradualmente variados no espaço, situação esta usual nos canais empregados em engenharia. ) Foi também considerado o efeito de parede, resultante do emprego de um canal de laboratório de pequenas dimensões, de modo a poder-se generalizar os resultados para o caso bidimensional. Os dados experimentais permitiram o teste dos modelos para cálculo de perdas de carga de Manning e do Perfil Logarítmico, estabelecendo-se correlações entre as perdas e as características geométricas da macro-rugosidade. Como contribuição ao tema foi proposta uma adaptação do modelo logarítmico considerando a hipótese de MORRIS & WIGGERT da separação do escoamento em uma zona de interferência, denominada de zona de hiper-turbulência e outra, de turbulência normal. Os resultados obtidos indicaram a validade do modelo proposto. Ainda como contribuição ao tema, a lei de distribuição probabilística das velocidades foi aplicada, obtendo-se uma estimativa dos parâmetros para as diferentes configurações geométricas. / The designation large-scale roughness is generally employed to describe spot or continuous elements artificially disposed in channel bottom, different from wall roughness or grain roughness, associated to the wall material. This work presents a theoretical and experimental study of the free flow in channels with prismatic rectangular elements regularly disposed on the bottom, named traverse blocks, which have large application in river stabilization and navigation works. The use of the large-scale roughness results in a great head loss for small depths and a progressive reduction of these losses as the depth increases. The theoretical analysis initially focused the traditional approach considering the logarithmic velocity distribution law. It was also analyzed the probabilistic velocity distribution law by CHIU, based on the maximum entropy principle. Specific studies about large-scale roughness, developed since 1960, where considered to guide the model testes, especially those by MORRIS & WIGGERT, SAYRE & ALBERTSON and KNIGHT & MACDONALD. Experimental data where collected from a laboratory channel and a technique for computing bottom shear stress were developed allowing to consider permanent gradually varied flows, a regular situation in engineering applications. The wall interference in total channel shear stress where considered in order to make data comparable with those from real two-dimensional flow. Practical correlations using geometriccharacteristics of the traverse block roughness and flow parameters where established considering Manning\'s Formula and the Logarithmic Law model. In order to achieve a better modeling of the phenomenon, a complementary term to the Logarithmic law was proposed, considering the hyper-turbulent layer over the roughness, and fit to the data. Finally, parameter estimation for the use of the CHIU\'s law with large-scale roughness where developed as another contribution to the matter.

Over the past three decades, technological innovations with respect to cemented paste backfill (CPB) as a means of ground support has allowed for increased production within the mining industry, management mine waste costs, as well as the improvement of the overall health and safety of underground mining operations. Despite the extensive use of this relatively new ground support material, many fundamental factors affecting the design of safe and economical CPB structures are still not well understood.Recently, a significant amount of academic and industry research has been conducted to better understanding the distribution of stress with respect to primary-secondary extraction sequencing for stope-and-fill mining operations. While current, as well as past research, as provided a wealth of knowledge on the distribution of stress through the fill material itself, it lacks in providing an examination into the mechanism by which stress is able to redistribute itself through the backfill material as well as within the surrounding rockmass. The scope of this work is to optimize stope-and-fill extraction sequencing through the analysis of stress distributions as well as local and global stability of multiple narrow verticalfully-drained backfilled stopes. Scientific investigations into the behavior of the CPB material and surrounding rockmass will result in animproved understanding of how to better implement engineered paste-fill materials as a means of ground support for underground mining operations. Numerical simulations (FLAC3D and RocScience) were utilized in analyzing hypothetical (literature) as well as site-specific (field) case studies. While these simulations confirm generalized stress behaviors within the backfill material for single and adjacent stopes, stress redistributions within the surrounding rockmass as well as the rock-pillarindicate the development of tensile and compressive zones. From these results, one is able to better approximate ground and CPB instability with respect to site-specific conditions, geometries, and material properties. These simulations have been validated with respect to published analytical solutions, numerical simulations, and site-measurements for single (isolated) and adjacent narrow vertical fully-drained backfilled stopes.

The salinization of groundwater resources is a widespread problem in arid agricultural environments. In Mewat, the amount of solutes dissolved in the water has become too high to use for drinking or agriculture. The only fresh water recharge to this bowl-shaped region is through precipitation, which is focused at the foothills of the mountain. The freshest water is found closest to the mountains and the salinity of the groundwater increases as the distance from the mountains increase. The pumps that supply the region with fresh water are located in the shrinking freshwater zone. Locally-monitored wells show the movement of salinity in the region, as the saline water encroaches upon the freshwater. This study aims to answer the following questions: How long until the region runs out of fresh water? What would it take to have sustainable fresh water supplies? Is it even possible to have sustainable fresh water supplies in this environment? In order to answer these questions, we will quantify potential futures for an arid, groundwater-dependent location in rural India, using numerical groundwater modeling to quantify interactions between human water use, infrastructure, and climate. Outcomes of this modeling study will inform sustainable management of groundwater resources