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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 385 for “"Subduction"”.
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Advances in Subduction Zone Processes
Subduction zones are an important recycling center at which material from the exterior of the Earth is transported to Earth's interior. The processes that occur along subduction zones have important implications for elemental cycles, geodynamics, and material mass transport. The cold, dense …
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Subduction zone wave guides : deciphering slab structure using intraslab seismicity at the Chile-Peru subduction zone
Subduction zones are regions of intense earthquake activity up to great depth. Sources are located inside the subducting lithosphere and, as a consequence, seismic radiation from subduction zone earthquakes is strongly affected by the interior slab structure. The wave field of these intraslab …
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Halogens and trace elements in subduction zones
… field strength elements in aqueous fluids in subduction zones was addressed by in-situ zircon solubility measurements in a hydrothermal diamond anvil cell. The zircon solubilities in aqueous fluids at 865-1025 oC and 6-20 kbar buffered by quartz are very low, ranging from 1.0 to 3.3 ppm Zr, …
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Liquefaction Triggering Model for Subduction Zone Earthquakes
… inaccurate results for megathrust earthquakes in subduction interfaces. To overcome this drawback and to achieve better prediction of liquefaction cases in subduction zones, this research intends to develop new empirical models that could be used for the prediction of liquefaction triggering in …
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Two-dimensional, viscous flow modeling of roll-back subduction : numerical investigation into the role of slab density in subduction dynamics
Observations of retreating subduction systems in the Mediterranean region suggest the density of subducting lithosphere is dynamically related to trench retreat rate and upper-plate deformation. Most numerical and analog studies of retreating subduction systems have not explored the effects of …
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Mass transfer and chemical interactions in subduction zones
Subduction zones are important sites of material recycling on Earth, with volatiles playing key roles in mass transfer processes and magma formation. This thesis investigates outstanding questions associated with a continuum of interrelated processes that occur as oceanic plates descend in …
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Mass Transfer and Chemical Interactions in Subduction Zones
Subduction zones are important sites of material recycling on Earth, with volatiles playing key roles in mass transfer processes and magma formation. This thesis investigates outstanding questions associated with a continuum of interrelated processes that occur as oceanic plates descend in …
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Compressible Convection and Subduction: Kinematic and Dynamic Modeling
Subduction is a dynamic and time-dependent process which requires time-dependent models for its study. In addition, due to the very high pressures within the Earth's interior, an evaluation of the role of compressibility in subduction studies should be undertaken. However, most subduction studies …
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Imaging subduction zones: slab structure, fluids, and fault slip
… what depth it is released during eventual plate subduction. The location of this fluid release has a profound impact on subduction zone processes, modulating megathrust fault slip, driving the production of arc magmas, and controlling the deep Earth water cycle. The magnitude of hydration depends …
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Early Water on Mars Hindered Subduction-Driven Plate Tectonics
… understanding why plate tectonics, particularly subduction-driven plate tectonics, failed to develop on Mars. Here, I investigate the possibility of subduction initiation in early Mars with both dry and hydrated scenarios to see if crustal hydration could have prevented the initiation of …
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Imaging of the Hellenic subduction zone by seismic tomography
The Hellenic subduction zone is a complicated tectonic boundary, along which transitions in the nature of subducted material are believed to occur. The objective of this study was to better constrain the subsurface geometry of the Hellenic subduction zone by increasing the resolution of an existing …
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Lithospheric dynamics of Earth’s subduction zones and Martian tectonic provinces
… investigates lithospheric dynamics of Earth’s subduction zones and Martian tectonic provinces on multiple time scales. In Chapter 2, I use geodetic observations to constrain the post-seismic viscoelastic deformation following the 1960 M9.5 Valdivia, Chile earthquake and quantify its stressing …
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Controls on earthquake rupture and triggering mechanisms in subduction zones
… triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M ≥ 7.5 earthquakes with fore-arc geological structure suggests that …
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Boron as a tracer for material transfer in subduction zones
Spät-miozäne bis quartäre Vulkanite der vulkanischen Front und der Back-arc Region der Zentralen Vulkanischen Zone in den Anden weisen eine weite Spannbreite von delta 11B Werten (+4 bis –7 ‰) and Borkonzentrationen (6 bis 60 ppm) auf. Die positiven delta 11B Werte der Vulkanite der …
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Seismic anisotropy and microseismicity: from crustal formation to subduction termination
… to, and re-equilibration with, the mantle in subduction zones. I investigate the structure of the crust and upper mantle of the Earth in two regions that represent different endmembers in this cycle through the analysis of microseismicity and seismic anisotropy, seeking to learn more about the …
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Controls on earthquake rupture and triggering mechanisms in subduction zones
… triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M 7.5 earthquakes with fore-arc geological structure suggests that …
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Lithospheric dynamics of Earth's subduction zones and Martian tectonic provinces
… investigates lithospheric dynamics of Earth's subduction zones and Martian tectonic provinces on multiple time scales ranging from short-term earthquake deformation to long-term tectonic loading. In Chapter 2, I use geodetic observations to constrain the postseismic viscoelastic deformation …
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Seismic Constraints on Slow Slip Events within the Cascadia Subduction Zone
… of geodetic GPS time series from the Cascadia subduction zone have revealed at least 30 resolvable slow slip events along the megathrust, ranging from northern California to southern British Columbia, since 1997. Many of the smaller and more recent events are barely resolvable with GPS, but …
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Investigating flat-slab subduction underneath South America using 4D numerical simulations
… 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 flat- to steep-dipping slabs, as …
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