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 95 for “"Subduction zones"”.
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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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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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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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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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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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Thermal Control on the Location of the Volcanic Arc at Subduction Zones
At subduction zones, where oceanic plates are recycled into the Earth’s interior, water released by the subducting plate initiates partial melts that form volcanic arcs. Partial melts can be present in a broad melting zone below a narrow volcanic arc. The second melting zone can be formed by mantle …
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The origin and behaviour of carbonate minerals in diverse environments: from subduction zones to asteroids
… and behaviour in three distinct environments: subduction zones in Earth’s mantle, a clay- rich near-surface terrestrial environment, and the CM parent asteroid(s). Subduction zones play an important role in the deep carbon cycle that includes the transport of carbon-bearing phases in subducting …
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Earthquake nucleation and rupture at a range of scales : laboratories, gold mines, and subduction zones
We measured spectral and time-domain properties of seismic events over a size range that spans magnitudes M [approx.] -2 to 8 in order to study earthquake source processes. In addition, we conducted laboratory experiments to study interseismic behaviors that can influence earthquake nucleation and …
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Volatile chemistry, and nitrogen sources and fluxes, in subduction zones : insights from the Izu-Bonin-Mariana Arc
… an ideal location to study volatile recycling in subduction zones as it is an intra-oceanic convergent margin (IOCM), where the entire sedimentary sequence is subducted and where a number of parameters, including sediment composition, slab dip and slab age, vary systematically along strike of the …
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A model of the crust and upper mantle structure of the Hellenic and Cyprus subduction zones constrained by gravity and seismic data
… of this region is dominated by the African plate subduction along the Hellenic and Cyprus trenches and collision between the Anatolian and Eurasian plates. The region is characterized by active volcanism, large-scale continental extension, uplift, slab rollback, slab break-off and slab-tear. …
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Studies of Magmatism by Trace Element Partitioning Between Clinopyroxene and Silicate Melt, Uranium-Series Disequilibria in Lavas From Subduction Zones, and Non-Traditional Stable Isotopes
Finally, in chapter 5, I report results of Fe-Mg isotopic analyses of a thermal migration experiment. Significant mass-dependent Fe-Mg isotopic fractionations occur in the melt-present portion of the experiment. I conclude that the positive co-variation of Fe-Mg isotopes could be an important …
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Surface Wave Derived Shear Velocity Structure of the Gamburtsev Subglacial Mountains, Transantarctic Mountains, and West Antarctica and Shallow Seismicity of the Mariana and Tonga Subduction Zones
… for tsunami hazard associated with the Tonga subduction zone. Through high precision location of aftershocks, we are able to determine the updip and downdip limits of seismicity associated with the mainshock. We are also able to relocate the mainshock location to a high degree of precision. In …
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Data-driven approaches towards understanding trace metal and magmatic processes in arc volcanoes, with applications to Java, Indonesia
… pronounced along tectonic plate margins like subduction zones (or "arcs"), where explosive volcanism is more common. The aforementioned social and economic pressures will necessitate a move towards "greener" economies, invariably leading to increased competition for natural mineral resources. …
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Modeling of the great earthquake seismic cycles
… developed with the aim of simulating the entire subduction process from earthquake (1 minute) to million years’ time scale, excluding only rupture propagation. The model employs elasticity, non-linear transient viscous rheology, and rate-and-state friction. It generates spontaneous earthquake …
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3D trench-parallel flow in the subduction region and correlation with seismic anisotropy direction
… the seismic anisotropy observations from various subduction regions of the world. In subduction zone backarcs both trench-parallel and trench-normal seismic anisotropy, or fast wave polarization direction of shear wave, are observed. In the mantle the general assumption is that seismic anisotropy …
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