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.
Results
Showing 1 to 19 of 19 for “"source mechanism"”.
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A numerical study of rupture propagation and earthquake source mechanism.
Thesis. 1976. Sc.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences.
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Investigation and characterization of the Direct Analysis in Real Time helium metastable beam open-air ion source: Mechanism of ionization, fluid dynamic visualization, and applications
<p>The DART ion source was introduced in 2005 at the ASMS Sanibel Conference and immediately afterward Professor Sparkman was contemplating of a way to get our lab this revolutionary mass spectrometry ionization technique. It did not take long because it was delivered to the Pacific Mass …
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INSIGHTS INTO ERUPTION DYNAMICS AND SHALLOW PLUMBING SYSTEM OF MT. ETNA BY INFRASOUND AND SEISMIC SIGNALS
… provide information on explosive phenomena and source mechanism. A more comprehensive knowledge of the source mechanism, as well as of the source depth into the conduit, can be achieved by exploring seismo-acoustic sources, exciting mechanical waves both in the volcano edifice and in the …
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Dynamics of the geomagnetically disturbed ionosphere as measured by GPS receivers and SuperDARN HF radars
… but not entering, the dayside cusp region. The source mechanism (enhanced electric fields) previously drawing the plasma from mid-latitudes and into the polar cap was no longer active, resulting in a fossil feature which persisted for several hours as it elongated in magnetic local time. …
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Understanding the operatic tenor's legitimate head voice: A comparative study of historical and modern pedagogical approaches
… the emergence of “mixed voice” as the purported mechanism for the tenor's upper register, and the introduction of a more mechanistic approach to register-blending or -unification as a means of developing the mixed voice source mechanism. In light of more recent discoveries in voice science, the …
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Acoustic emissions in hydraulic fracturing of Barre granite
… energy, or their frequency content while the source location and source mechanism can be inferred from events. The AE data are analysed in conjunction with water pressure, high resolution images, and high speed video taken during the experiment. Section 3 of this work outlines the selection …
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Palynology of late-glacial and postglacial sediments in Georgian Bay, Ontario, Canada, as related to the Great Lakes history /
This investigation comprises three parts: (1) the source, mechanism of transport, and distribution of pollen, spores and other palynomorphs in Georgian Bay bottom sediments and a comparison of these data with the contemporary vegetation, (2) the relative significance of fluvial transportation of …
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Deep learning framework bridges lab and field scale microseismic focal mechanism
… moment tensor inversion of microseismic source mechanisms is particularly useful as these tensors can highlight the kinematics and kinetics of subsurface deformation. However, these inversions can be difficult to constrain and automate in field applications owing to the requirement of a …
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Utilizing Changes in Repeating Earthquakes to Monitor Evolving Processes and Structure Before and During Volcanic Eruptions
… are two or more earthquakes that share the same source location and source mechanism, which results in the earthquakes having highly similar waveforms when recorded at a seismic instrument. Repeating earthquakes have been observed in a wide variety of environments: from fault systems (such as the …
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Microseismic mapping and source characterization for hydrofracture monitoring : a full-waveform approach
… 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 with mechanisms and locations similar to a nearby template event. Second, we extend the …
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Investigation on Mt. Etna dynamics by seismic and acoustic signals (August 2007-December 2010)
… dynamics of the plumbing system, and define the source-mechanism of acoustic events at Mt. Etna, infrasound signals-continuously recorded by Istituto Nazionale di Geofisica and Vulcanologia- were analyzed in this thesis, jointly with some seismic signals. In particular, we focused on the period …
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Studies on earthquake location and source determination using coda waves
… body waves to model earthquake location and source properties. A recent technique known as coda wave interferometry utilises the cross correlation of coda waves to constrain changes in source properties between earthquake pairs. This thesis focuses on extending coda wave interferometry by …
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Studies on earthquake location and source determination using coda waves
… body waves to model earthquake location and source properties. A recent technique known as coda wave interferometry utilises the cross correlation of coda waves to constrain changes in source properties between earthquake pairs. This thesis focuses on extending coda wave interferometry by …
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Sound Radiated from Turbulent Flow over Two and Three-Dimensional Surface Discontinuities
… have been performed to understand the sound source mechanism in turbulent boundary layer flow over two and three-dimensional surface discontinuities whose height is smaller than the incoming boundary layer thickness. The work was performed in two different types of boundary layers: a wall-jet …
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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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Setting Constraints on the Lunar Exosphere: A Comprehensive Analysis of Velocity Resolved Sodium and Potassium Line Profile Measurements
… photon stimulated desorption (PSD) is the major source mechanism for the lunar sodium exosphere near subsolar points while contributions from charged particle sputtering and micrometeoroid impact vaporization are more important near the dawn and dusk terminators. For potassium, the exosphere …
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Distributed acoustic sensing: modelling, full waveform inversion, and its use in seismic monitoring
… supports a machine learning study for extracting source mechanism information from DAS data, and to support FWI. The shape of the DAS fiber, both on large-scales such as when it tracks a deviated well, or on small scales when it is wrapped in some characteristic shape affects the sensitivity of …
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Investigating Volcanic and Glacial Processes Using Microseismicity
… storage region. The seismicity and earthquake source mechanisms suggest that melt travels along a pathway that is approximately vertical, and laterally offset from the main shallow melt storage region by 12 km. However, it is also likely that an aseismic melt feed exists directly under …
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Catastrophic Tsunamis In the Indonesian Archipelago
… Field surveys results, and analysis of the source mechanism and distribution of the resulting tsunami waves along the coast, shows that each near-field tsunami generated within the subduction zone is unique and complex. Scientists have urged the public and policy makers to consider all …