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 15 of 15 for “"hydrofracture"”.
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Microseismic mapping and source characterization for hydrofracture monitoring : a full-waveform approach
… improve the microseismic mapping capability for hydrofracture monitoring by using full-waveform information and understand fracturing mechanisms via microsesimic source mechanism inversion. First, we develop an array-based correlation approach to improve the detection of small magnitude events …
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Some rock mechanics problems with application for hydraulic fracturing
… an apparent increase in diffusivity. Whether the hydrofracture crosses or arrests on the pre-existing fault is also affected by surface roughness, differential stresses, and fault slip mode (i.e., stable or stick-slip sliding). Calibrated piezoelectric transducers were used to measure acoustic …
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Remote sensing of rapidly draining supraglacial lakes on the Greenland Ice Sheet
… to days) by hydraulically-driven fracture (“hydrofracture”) in the summer. Hydrofracture can deliver large meltwater volumes to the ice-bed interface and open-up surface-to-bed connections, thereby routing surface meltwater to the subglacial system, altering basal water pressures and, …
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Investigating Volcanic and Glacial Processes Using Microseismicity
… or not the crevasses observed are induced by hydrofracture. I use a combination of seismic observations and simple physical models to investigate these fundamental geophysical processes. Understanding the magmatic plumbing of a volcano is important for attempting to improve eruption …
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Experimental studies of melting and crystallization processes in planetary interiors
… ow through the Greenland ice sheet driven by hydrofracture of water through ice. The results show that melt water in the ablation zone of Greenland has almost immediate access to the base of the ice sheet in areas with up two kilometers of ice. Chapter 4 is an experimental study of two hydrous …
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UAV-based investigations into the hydrology and dynamics of the Greenland Ice Sheet
… are more likely to display ponding and rapid hydrofracture than in extensional regimes, where continuous slow drainage is typical. Continued high-resolution observations are necessary to further identify key controls on the hydrological influences of Greenland Ice Sheet dynamics.
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Experimental studies of melting and crystallization processes in planetary interiors
… flow through the Greenland ice sheet driven by hydrofracture of water through ice. The results show that melt water in the ablation zone of Greenland has almost immediate access to the base of the ice sheet in areas with up two kilometers of ice. Chapter 4 is an experimental study of two hydrous …
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Influence of meltwater on Greenland Ice Sheet dynamics
… basin generates tensile stresses that promote hydrofracture beneath the lake. As these precursors are likely associated with the introduction of meltwater to the bed through neighboring moulin systems, our results imply that lakes may be less able to drain in the less crevassed, interior …
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Influence of meltwater on Greenland Ice Sheet dynamics
… basin generates tensile stresses that promote hydrofracture beneath the lake. As these precursors are likely associated with the introduction of meltwater to the bed through neighboring moulin systems, our results imply that lakes may be less able to drain in the less crevassed, interior …
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An investigation into pixel- and object-based classification approaches for the detection of dolines on the surface of Antarctic ice shelves
… incision or through the opening of fissures by hydrofracture. Vertical, meltwater-induced fracture propagation through the ice shelf column as well as ring fractures produced around dolines during hydrostatic rebound have been associated with catastrophic collapse events of ice shelves on the …
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Bayesian source inversion of microseismic events
… are linked to anthropogenic activities including hydrofracture of gas and oil reservoirs, mining events and extraction of geothermal fluids. Source inversion is very sensitive to uncertainties in both the model and the data, especially for low magnitude, namely microseismic, events. Many of the …
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Investigating the surface hydrology of Antarctic ice shelves using remote sensing and machine learning
… ice-shelf instability and potential collapse via hydrofracture or militate against potential ice-shelf instabilities by forming drainage systems that export surface meltwater off the ice-shelf edge. It is crucial, therefore, that water area and volume on Antarctic ice shelves are accurately …
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Evolution of basal channels, ice fracture, and surface meltwater, and implications for the stability of the Roi Baudouin Ice Shelf
… to increase the vulnerability of ice shelves to hydrofracture and/or estuarine weakening. Therefore, through these mechanisms, basal channels are considered to have the potential to precondition ice shelves to instability. The Roi Baudouin ice shelf (RBIS), located within the East Antarctic Ice …
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Modelling the Hydrology of the Greenland Ice Sheet
… lakes are able to drain by a simulated hydrofracture mechanism if they reach a critical volume. Once water is at the ice / bed interface, discharge and hydraulic head within subglacial drainage pathways are modelled using the third model component. This consists of an adaptation of a …
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Crustal heterogeneities and complexities of fault processes
… change in the principal stress directions. Hydrofracture processes in the tensile quadrants and viscoelastic relaxation at depth may contribute to lower the effective rigidity of the medium surrounding the asperity. According to the present model, foreshocks may be interpreted as induced, …