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 57 for “"Seismic tomography"”.
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Theoretical and computational studies in seismic tomography
Seismic tomography allows us to study the interior structure of the Earth on a range of lengthscales, with the method of waveform inversion being a promising and relatively recent development. In this work, we present new theoretical methods which may contribute to the study and solution of seismic …
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Multiresolution spherical wavelet analysis in global seismic tomography
Every seismic event produces seismic waves which travel throughout the Earth. Seismology is the science of interpreting measurements to derive information about the structure of the Earth. Seismic tomography is the most powerful tool for determination of 3D structure of deep Earth's interiors. …
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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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Seismic tomography and surface deformation in Krýsuvík, SW Iceland
… geothermal energy that is currently experiencing seismic swarm activity and active surface deformation. Understanding the subsurface structure of the area is of great scientific and practical significance. Using permanent and temporary seismic stations deployed in the region, we captured an …
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Constraints on mantle convection from seismic tomography and flow modeling
In this thesis I combine high resolution seismic tomography and realistic flow modeling to constrain mantle convection. The bulk of the data used in the tomographic imaging are millions of P, pP and pwP travel time residuals, read from high frequency seismic records. The distribution of earthquakes …
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Seismic Tomography for the Integrity Assessment of Earthen Dams and Levees.
… examines the use of a non-invasive geophysical seismic method to provide additional information where the usual visual inspection is insufficient and the comboring investigation is not an option. Even though seismic techniques provide valuable information of the subsurface strata, the …
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Passive Seismic Tomography and Seismicity Hazard Analysis in Deep Underground Mines
Seismic tomography is a promising tool to help understand and evaluate the stability of a rock mass in mining excavations. Lab measurements give evidence that velocities of seismic wave propagations increase in high stress areas of rock samples. It is well known that closing effects of cracks under …
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Probing the interior of an active volcano: Three-dimensional seismic tomography at Montserrat
… the style and time-scales of eruptions. Seismic tomography can provide detailed resolution of the physical characteristics of complex three-dimensional structures in the subsurface, and has been successfully employed at several active volcanoes to constrain the structure of their magmatic …
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An exploration of the effect of anisotropy on seismic tomography in different geological settings
Seismic tomography is used in wide ranges to understand the inner structure of Earth based on the dependence of seismic velocity to temperature and other factors such as composition, volatile content, and seismic anisotropy. Despite it is well known that the mantle is seismically anisotropic, the …
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Seismic Wave Velocity Variations in Deep Hard Rock Underground Mines by Passive Seismic Tomography
… of the rock mass associated with mining-induced seismicity is poorly-understood. Passive seismic tomography is a tool with which the performance of a rock mass can be monitored in a timely manner. Using the tool of passive seismic tomography, the advance rate of operation and mining designs can …
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Seismic Tomography at Volcanic Rift Zones and Transpressional Plate Boundaries Askja Caldera and Macquarie Island
… thesis consists of two main parts: imaging the seismic structure beneath Askja caldera, Iceland, located in a divergent tectonic setting, and Macquarie Island, south-west Pacific, that sits within an intra-oceanic transpressive regime. For decades, the presence or absence of a shallow magma body …
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A study of the structure of the Belgian crust by Moho determination and local seismic tomography
… into the middle and lower crust. Until now, only seismic profiles and gravimetric and magnetic data gave some insights. The general aim of this thesis is to improve the understanding of the lower/middle crustal structure of Belgium. This will be achieved by determining the Moho depth and …
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New Constraints For Convergent Margin Plate Tectonic Reconstructions From Imaged And Predicted Mantle Structure
… from imaged and predicted mantle structure using seismic tomography and forward geodynamic models, respectively. We apply recently-developed P-wave tomographic filtering to create ‘synthetic tomography’ of the geodynamic models. East Asia is one the most uncertain areas in global plate tectonics. …
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Characterization of secondary mantle convection from geophysical data and models
… using the geophysical data and models such as seismic tomography models and geoid anomalies. We used three seismic tomography models, SEMUCB-WM1, SAVANI and S40RTS to infer the lithosphere/asthenosphere boundary, and the destabilization of the lithosphere, induced by secondary mantle …
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Double-Difference Tomography Applied to Monitoring of Geologic Carbon Sequestration in the Aneth Oil Field, Utah
Double-difference seismic tomography is performed on a carbon sequestration operation in the Aneth Oil Field in southeast Utah as part of a Department of Energy initiative on monitoring, verification, and accounting of sequestered CO2. A total of 1,211 seismic events were recorded from a borehole …
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Testing the hypothesis of the slab-plume interaction on the formation of the Yellowstone hotspot system
… plume or only upper mantle processes. Recent seismic tomography images suggest the existence of hot mantle upwelling beneath the present-day Yellowstone, lending support to the plume hypothesis. However, the effect of the Farallon slab on the temporal evolution of the hypothesized plume …
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Teleseismic transmission and reflection tomography
The aim of seismic tomography is to determine a model of Earth properties that best explain observed seismic data. In practice, the limitations placed on our observations and computational capabilities force us to make a number of decisions about the scales and parameterizations of models, the …
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Defining Stress Changes Ahead of a Tunnel Face and Design of a Data Acquisition System
… tunnel construction continues to claim lives. A seismic method to aid in increasing safety during excavation is tomography. Seismic tomography is a non-invasive technique to map the stress changes induced by mining ahead of the active face. Seismic tomography maps the velocity distributions of …
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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
… is one of the most dynamically complex and seismically active tectonic settings on Earth. The dynamic evolution 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 …
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Ambient seismic noise tomography of the southern United States and seismic inversion with dictionary learning using unsupervised machine learning.
Seismic tomography and inversion are well-established methods to understand deep subsurface structures. These techniques are particularly effective in delineating complex crustal architectures, which often deviate from simplified textbook models. High-resolution seismic tomography enables the …
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