Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 189-210). Also available in print.

Thesis (M.S. in geology)--Washington State University, August 2010. / Title from PDF title page (viewed on July 28, 2010). "School of Earth and Environmental Sciences." Includes bibliographical references (p. 134-140).

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 83-85).

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 189-210). Also available online.

No description available.

Large bodies of keratophyric tuffs and keratophyric flows from Harrison Mills, British Colombia are described structurally and petrologically. The origin of the albitic feldspar in these rocks is discussed and concluded to be primary. Petrological comparisons are made between the tuffs and the flows. Both types of rocks were artificially fused to glasses, and the refractive indices of these glasses are compared. From these studies the tuffs and the lavas are concluded to be consanguineous. The keratophyric flows were analysed chemically and found similar to keratophyric rocks from other localities. The origin of the lavas is discussed. It is concluded that these rocks were probably formed by differentiation of a trondjhemitic magma possibly contaminated by soda rich sediments. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The processes associated with magma injection at shallow depths within the crust have been the topic of many geophysical studies, some investigating the seismicity that accompanies volcanic activity and others attempting to map the subsurface extent and geometry of the resulting magma bodies. The aim of this study is to obtain a better understanding of these processes by investigating the nature of seismic signals that accompany volcanic eruptions and by seismically imaging a magma body beneath a mid-ocean ridge, both located on, or adjacent to Iceland. The seismic phenomena associated with the 1996 Vatnajӧkull subglacial eruption in central Iceland, have been studied using data recorded by both temporary (HOTSPOT) and permanent (SIL) seismic networks. These networks comprise 60 broadband and short-period three-component seismographs and cover most parts of the country. Two very active volcanic systems, Bárdarbunga and Grimsvӧtn, are situated underneath the Vatnajokull ice cap. The volcanoseismic signals recorded there were categorised according to their waveform shape and frequency content, into three groups: (a) low-frequency events (1-2 Hz); (b) mixed-frequency events (1-4 Hz); and (c) volcanic tremor. The eruption was preceded by intense seismic activity which began with a = 5.6 earthquake located at the Bárdarbunga volcanic system. The epicentres of the earthquake swarm that followed the M(_w), = 5.6 event initially delineated the Bárdarbunga caldera rim and then migrated towards Grimsvӧtn, to a place where a fissure was later observed. Pre-eruptive tremor started at least two days before the eruption as a harmonic signal around five narrow frequency bands (0.5-0.7, 1.6, 2.2, 2.8 and 3.2 Hz). Co-eruptive tremor started as a broadband, continuous signal which evolved into low-amplitude background tremor interrupted by high-amplitude, cigar-shaped bursts. Further analysis revealed that continuous tremor and the cigar-shaped bursts had all the characteristics of low- dimensional chaotic signals. Geophysical and geochemical evidence suggest that a lateral migration of magma from Bárdarbunga facilitated the rupture of the roof of a magma chamber, situated at the fissure area, which subsequently erupted as tephra on the glacier. The second phase of the RAMESSES (Reykjanes Ridge Axial Melt Experiment: Structural Synthesis from Electromagnetic and Seismics) experiment involved the acquisition of multichannel seismic reflection data from 39 along- and across-axis lines shot over the magmatically active 57º 45'N axial volcanic ridge. The data from one along-axis line were processed using a variety of techniques that mainly aimed at reducing the large amount of coherent noise present, a result of scattered energy at the rough seabed. The final processed section revealed a number of reflection events that could be interpreted as intra-crustal reflections, originating from the interface between pillow lavas and sheeted dykes, and from the top part of a thin melt lens.

Thesis (M.S.)--Oregon State University, 1985. / One map folded in pocket. Typescript (photocopy). Includes bibliographical references (leaves 85-90). Also available online.

Thesis (Ph.D. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 236-252).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.