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 24 for “"Microseismicity"”.
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Investigating Volcanic and Glacial Processes Using Microseismicity
… the Earth′s poles, can be investigated using microseismicity, emitted when these fluids and bodies release kinetic energy as they move. I use this microseismicity to study: melt moving from the deep crust and feeding Bardarbunga volcano, Iceland, before and after an eruption; icequakes at the …
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Seismic anisotropy and microseismicity: from crustal formation to subduction termination
… endmembers in this cycle through the analysis of microseismicity and seismic anisotropy, seeking to learn more about the stresses in these environments and how they are manifest in the structure of the subsurface. In Iceland, new oceanic crust is accreted episodically within the volcanic rift …
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Analysis and interpretation of clustered microseismicity at geothermal and petroleum reservoirs
This thesis presents the analysis and interpretation of four microearthquake clusters near geothermal and petroleum reservoirs. One cluster was induced during a controlled hydraulic fracture experiment conducted by Atlantic Richfield Corporation (ARCO). The other three clusters occurred near …
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Ground motions and source mechanisms of earthquakes in multiscales : microseismicity to macroseismicity
This thesis focuses on the source mechanisms of Earthquakes of different scales, from the micro-seismicity in oil/gas fields in Oman, to moderate earthquakes in Kuwait, and finally to pico-seismicity, i.e. acoustic emission, in the laboratory. To investigate the source mechanisms as well as their …
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Investigation of the Pre to Post Peak Strength State and Behaviour of Confined Rock Masses Using Mine Induced Microseismicity
… rock and measurement of acoustic emissions, the microseismicity can be used to identify, fracture initiation, coalescence of fractures (yield), localization (peak-strength), accumulation of damage (post-peak) and ultimate failure (residual strength) leading to aseismic behaviour. The case studies …
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Quantitative Analysis of Acoustic Emission From Rock Fracture Experiments
… sponse test where both AE (10 kHz - 1 MHz) and microseismicity (MS) (1 Hz - 10 kHz) were monitored. Using the calibration information, magnitude, stress drop, dimension and energy were successfully estimated for 21 AE events recorded in the tensile region of the tunnel wall. Magnitudes were in …
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Seismic and gravitational studies of melting in the mantle's thermal boundary layers
… extraction system in the upper crust such as microseismicity caused by thermal cracking and high temperature hydrothermal vent systems observed on the seafloor. The third study uses two-dimensional global pseudospectral seismic wave propagation modeling to characterize the sensitivity of the …
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Seismic and gravitational studies of melting in the mantle's thermal boundary layers
… extraction system in the upper crust such as microseismicity caused by thermal cracking and high temperature hydrothermal vent systems observed on the seafloor. The third study uses two-dimensional global pseudospectral seismic wave propagation modeling to characterize the sensitivity of the …
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Seismicity associated with magmatic intrusions: insights from the Reykjanes Peninsula, southwest Iceland
… and the magmatic intrusions that precede them. Microseismicity is a powerful lens through which to view these processes, providing the means to track melt movement as it triggers earthquakes in the surrounding crust. This dissertation makes use of an exceptional seismic dataset recorded by the …
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Microseismic Monitoring of a Room and Pillar Retreat Coal Mine in Southwest Virginia
… retreating and ultimately reduce risk to miners. Microseismicity has been proven to be an acceptable method of monitoring stress redistribution in underground coal mines and assist in explaining rockmass behavior (Luxbacher, et al, 2007). An array of geophones was placed underground along a single …
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Exploring subsurface ground water and geochemical rock interactions during drainage of a surface water reservoir in Switzerland
… of a nearby surface water reservoir induced microseismicity In the surrounding rocks. The GTS is a network of closely monitored tunnels and boreholes approx 300-500m below ground surface.Characterisation of background geochemical conditions over a two-year period consisted of a time series of …
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Micro-seismic observations in Leeu Gamka, Karoo, South Africa
This thesis documents a microseismicity study in the interior of South Africa. The study area is centred on Leeu Gamka in the Western Cape province, a tectonically stable intraplate setting and is therefore expected to be seismically quiet. The International Seismological Centre (ISC) catalogue …
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Deep learning framework bridges lab and field scale microseismic focal mechanism
… that these systems can induce earthquakes. Microseismicity, which has lower magnitude and occur more often than conventional earthquakes, is a key diagnostic tool for these sites. Where possible, moment tensor inversion of microseismic source mechanisms is particularly useful as these …
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Microseismic mapping and source characterization for hydrofracture monitoring : a full-waveform approach
… differential stress like the Bonner sands, the microseismicity occurs predominantly by shearing along natural fractures subparallel to the average fracture trend. Finally, the full-waveform based complete moment tensor inversion method is applied to a dual-array hydrofracture monitoring dataset …
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Tectonic earthquake swarms in the Northern Volcanic Zone, Iceland
Microseismicity offers an opportunity to image subsurface deformation at exceptionally high spatial and temporal resolution. This may be related to a diverse range of processes, including fore- and aftershocks to destructive earthquakes on large faults, magma movement at volcanoes, or the gradual …
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Volcanic deformation as an indicator of mechanical stability and eruption susceptibility
… on eruption. In particular, models indicate that microseismicity (induced by the expansion of the Axial magma reservoir) serves as both an eruption precursor and an eruption buffer, reducing crustal stress and delaying model predictions of eruption. Despite stress release via seismicity, …
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A Parameterized Approach to Partitioning Between Focused and Diffuse Heat Output and Modeling Hydrothermal Recharge at The East Pacific Rise 9°50´N
… recharge through an area of 10⁵ m² elucidated by microseismicity in the oceanic crust I find that anhydrite precipitation is likely to result in rapid sealing of pore space in the recharge zone. This would lead to rapid decay of hydrothermal venting, which is contrary to observations. Then I …
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Geomechanical Reservoir Model Calibration and Uncertainty Assessment from Microseismic Data
… hypothesis, the distribution of the resulting microseismicity clouds can be viewed as monitoring data that carry important information about the spatial distribution of rock permeability. We apply the ensemble Kalman filter (EnKF) to integrate the resulting continuous seismicity map to estimate …
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Towards monitoring volcanoes in Iceland and Hawai’i with seismic velocity variations
… including those of surface deformation and microseismicity, in order to understand the dynamics of a volcanic system.
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Automated seismic event location by waveform coherence analysis
… datasets. A first one related to mining induced microseismicity in a coal mine in the northern Germany (chapter 3). In this case we successfully located 391 microseismic event with magnitude range between 0.5 and 2.0 Ml. To further validate the location method I compared the retrieved locations …
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