Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 37 for “"Plate boundaries"”.
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Dynamic processes at submarine plate boundaries
The theory of plate tectonics provides a simplified yet powerful framework to describe the motion of lithospheric plates and the deformation that takes place at their boundaries. Although plate boundaries represent a small fraction of the earth’s surface, the localisation of stresses, resulting …
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The gravity field and plate boundaries in Venezuela
… motion between the North and South American plates. Because the Caribbean mountains are partially isostatically compensated, while the Venezuelan Andes are above isostatic equilibrium, this suggests that the relative motion of the Caribbean plate with respect to the South American plate is …
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The gravity field and plate boundaries in Venezuela
… motion between the North and South American plates. Because the Caribbean mountains are partially isostatically compensated, while the Venezuelan Andes are above isostatic equilibrium, this suggests that the relative motion of the Caribbean plate with respect to the South American plate is …
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High-resolution temporal records of magmatism, sedimentation, and faulting at evolving plate boundaries
… with its origin as an accreted oceanic plateau, possibly developed above a long-lived Yellowstone hot spot. Chapter 3 quantifies magma emplacement rates in a large, granitoid intrusive complex (Golden Horn batholith) that was emplaced during Paleogene ridge-trench interaction. Parts of …
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Seismic Tomography at Volcanic Rift Zones and Transpressional Plate Boundaries Askja Caldera and Macquarie Island
… boundary between the Australian and Pacific plates. While incipient subduction has been proposed for the northern and southern segments of the ridge, the plate configuration underlying Macquarie Island, located within the central segment, remains unclear. In this part of the study, …
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Three-dimensional thermo-mechanical modeling of deformation at plate boundaries : case study San Andreas Fault System
… the North American terranes towards the Pacific plate and the landward migration of the San Andreas plate boundary. One of the theories suggests that the Pacific plate first cools and captures the uprising mantle in the slab window, and then it causes the accretion of the continental crustal …
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Evolution of Deformation Along Restraining Bends Based on Case Studies of Different Scale and Complexity
Globally, deformation along obliquely converging plate margins produce a wide variety of complex fault patterns, including crustal pop-ups, fault duplex structures, restraining bends, and flower structures. Depending on the plate velocity, plate obliquity, crustal rheology, length-scale, and …
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Thermal Management In Friction Stir Welding of Aluminum Alloys
… conditions at tool, work piece and backing plate boundaries. </p> <p>Various thermal management methods are applied at work-piece, tool and backing plate boundaries. This is achieved by performing series of welds using various parameter sets in regular lab air, submerged under water and …
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Ps receiver function imaging of crustal structure and Moho topography beneath the Northeast Caribbean.
The Caribbean plate consists of accreted different geologic terrains bounded by a system of complex plate boundaries. We conduct P-to-S receiver function studies of the Northeast Caribbean in order to image the plate boundary and study the major forces driving tectonics and strain distribution in …
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Modeling, Visualizing, and Understanding Complex Tectonic Structures on the Surface and in the Sub-Surface
<p>Plate tectonics is a relatively new theory with many details of plate dynamics which remain to be worked out. Moving plates can interact by divergence, lateral sliding, convergence, or collision. At a convergent plate boundary, a lithospheric slab of oceanic crust and upper mantle is subducted …
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Seismic anomalies in stable continents: exploring earthquake clusters and hidden faults in Southern Africa
… geographically far removed from active tectonic plate boundaries. Nevertheless the region is experiencing ongoing seismicity, often in transient clusters rather than along lineaments. The distance of these earthquakes to plate tectonic boundaries raises questions about the mechanism leading to …
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The Mechanisms and Triggering of Earthquakes in the Ridge-Transform Environment
The theory of plate tectonics introduced a paradigm shift in the way we view and study our planet. Many of the world's plate boundaries, however, are beneath our oceans making data collection, the key to furthering our knowledge about these zones, difficult. Recent advances in research vessels, …
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Structure and Accretion at Mid-Ocean Ridges With High Magma Supply: Perspectives From Seafloor Escarpments and Iceland
… and tectonic processes beneath these divergent plate boundaries and how these processes may vary along the spreading axis. Investigations that combine geologic relationships and magnetic properties continue to yield fundamental tools for understanding and constraining seafloor spreading …
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Investigating flat-slab subduction underneath South America using 4D numerical simulations
The Nazca Plate recycling underneath South America is an ideal example of modern subduction, which provides an opportunity to study mechanisms of flat-slab subduction and the nature of mantle seismic structures. Subduction occurring at this location is characterized by along-trench variation from …
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The heterogeneity and volatile content of Earth’s mantle, magmas and crust
… transfer from crustal generation at divergent plate boundaries (e.g., mid-ocean ridges) to recycling of ocean crust at subduction zones. In Chapter 4, I use the H2O content of nominally anhydrous minerals in plutonic arc cumulates to elucidate the H2O content of the melts from which the rocks …
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Ultrasonic sensor platforms for Non-Destructive Evaluation
… capable of generating the A0 Lamb wave mode in plate specimens. An embedded Kalman filter gives the robots a positional accuracy of 10mm. A computer simulator, to facilitate the design and assessment of the reconfigurable scanner, is also presented. Transducer behaviour has been simulated using …
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The role of the Picuris orogeny in the tectonic evolution of Proterozoic North America
… gives insight into fundamental components of plate tectonics, and sheds light onto processes at work at modern plate boundaries, in which mid- and lower-crustal rocks are generally hidden from view.</p> <p>This study focuses on the growth of North America during the Proterozoic. Researchers …
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Modelling the controls on melt generation during continental extension and breakup
… oceanic floor between the two continental<br/>plates. Although the concept of continental rifting is accepted within the scientific<br/>community, it is still debated what controls the volume and composition of igneous<br/>material generated at these constructive plate boundaries. Here I …
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Contractional tectonics : the Himalayan orogen and Perdido fold-thrust belt
… of collisional orogenic belts along convergent plate boundaries. It is commonly structurally defined as three stacked units separated by two fault systems: the Main Central thrust (MCT) and South Tibet detachment (STD). The development and emplacement of the middle unit, the Himalayan …
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Insights into the edifice stability of oceanic volcanoes from direct shear experiments and numerical models
Volcanoes are mainly related to plate boundaries but can also be found at intraplate settings related to mantle hot spots. Moreover, volcanoes can be located on land or in the ocean, i.e., coastal and ocean island volcanoes (oceanic volcanoes). Beyond the primary hazards commonly associated with …
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