Obsidian Dome is a 550-650 year old, 1.5 by 1.8 km extrusion of high silica rhyolite situated along the Inyo Craters in eastern California. Field, and observations of drill core, reveals discrete metre-scale thick zones of rhyolitic glass exposed along the margin of Obsidian Dome as well as within its interior. Millimetre-scale flow-banded obsidian, pumice and rhyolite range from planar to chaotically folded, the latter a product of ductile, compressive deformation. Fractures, some of which display en-echelon splitting patterns are a result of brittle failure. Taken together, these features along with others, result from flow during lava dome growth and suggest complex emplacement patterns signified by vesiculation, crystallization and repeated brittle-ductile deformation, owing to episodic crossing of the glass transition. Evidence further shows that gas loss from the system occurred due to explosions, pumice formation and also brecciation of the melt as it episodically crossed the glass transition. Loss of gas by these mechanisms along with the inherent high viscosity of rhyolite melt explains the large amount of glass found on and within Obsidian Dome and other similar rhyolite extrusions in comparison to less silica-rich systems.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1989. / Includes bibliographical references. / Microfiche. / xx, 277 leaves, bound ill. 29 cm

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [137]-147).

Mémoire (M.ScA.)- Université du Québec à Chicoutimi, 1982. / 6 cartes dans une pochette. "Mémoire présenté en vue de l'obtention de la maîtrise es sciences appliquées" CaQCU CaQCU Document électronique également accessible en format PDF. CaQCU

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 122-136).

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.

Thesis (M. Sc. (Geology))--Rhodes University, 2006.

Research into the mechanisms responsible for the lasting, cyclic activity at Masaya volcano can lead to a better understanding of persistently degassing volcanoes. This study is greatly enhanced by the integration of dynamic micro-gravity, deformation and gas flux measurements. The acquisition of extended temporal and spatial geophysical data will also allow for the development of robust models for the dynamics of magmatic systems. Masaya volcano, Nicaragua, is one of the most active systems in Central America, making it an excellent natural laboratory for this study. It is noted for repeated episodes of lava lake formation, strong degassing and subsequent quiescence. Ground-based geophysical measurements show two episodes of similar magnitude gravity decreases in 1993-1994 and 1997-1999, separated by a period of minor gravity increase. A major increase in S02 gas flux from 1997-1999 correlates well with the most recent episode of gravity decrease. The gravity changes are not accompanied by deformation in the summit areas and are interpreted in terms of sub-surface density changes. The persistent degassing at Masaya suggests that up to -15 krrr' of magma may have degassed over the last 150 years, only a minute fraction of which has been erupted. Furthermore, thermal flux calculations suggest that 0.5 krrr' of magma (the estimated volume of the shallow reservoir) would cool from liquidus to just above solidus temperatures in only 5 years. The high rates of degassing and cooling at open-system volcanoes such as Masaya raise questions as to the ultimate fate of this degassed and cooled magma. A number of models have been proposed to explain this, but the most likely mechanism to explain persistent activity at Masaya and other similar volcanoes is convective removal of cooled and degassed magma and subsequent recharge by volatile-rich magma from depth. Another fundamental question in modem volcanology concerns the manner in which a volcanic eruption is triggered; the intrusion of fresh magma into a reservoir is thought to be a key component. The amount by which previously ponded reservoir magma interacts with a newly intruded magma will determine the nature and rate of eruption as well as the chemistry of erupted lavas and shallow dykes. The physics of this interaction can be investigated through a conventional monitoring procedure that incorporates the Mogi model relating ground deformation (~) to changes in volume of a magma reservoir. Gravity changes (.1.g)combined with ground deformation provides information on magma reservoir mass changes. Models developed here predict how, during inflation, the observed .1.gI~ gradient will evolve as a volcano develops from a state of dormancy through unrest into a state of explosive activity.

Lava flows are common at volcanoes around the world and on other terrestrial planets, but their behavior is not fully understood. In Hawai`i, advances in remote sensing are offering new insights into lava flow emplacement. In this dissertation, I develop new techniques using satellite-based synthetic aperature radar, aerial photographs, and airborne lidar to produce three-dimensional high-resolution maps of lava flows from data collected before, during, and after emplacement. These new datasets highlight complex lava channel networks within these flows, which are not incorporated into current predictive or probabilistic lava flow models yet may affect flow behavior. I investigate the origin and influence of these channel networks through morphologic analysis of underlying topography, network topology, and flow morphology and volume. Channel network geometries range from distributary systems dominated by flow branching around local obstacles to tributary systems constricted by topography. I find that flow branching occurs where the flow thins over steeper slopes and that the degree of flow branching, network connectivity, and longevity of flow segments all influence the final flow morphology. Furthermore, because channel networks govern the distribution of lava supply within a flow, changes in the channel topology can dramatically alter the effective volumetric flux in any one branch, which affects both flow length and advance rate. Specifically, branching will slow and shorten flows, while merging can accelerate and lengthen them. To test these observations from historic eruptions and morphologic analysis, I use analogue experiments to simulate the interaction of a lava flow with a topographic obstacle and determine the conditions under which the flow branches and the effects of the bifurcation on flow advance rate. These experiments support the earlier results but also demonstrate the importance of flow dynamics and obstacle morphology on governing when flows may overtop obstacles. Consideration of channel networks is thus important for predicting lava flow behavior and mitigating flow hazards with diversion barriers. One video of Kilauea lava flow activity from 2003-2010 accompanies this dissertation as a supplemental file. This dissertation includes both previously published and unpublished co-authored material.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-05-16T12:48:27Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTAÇÃO_DELFINO PEREIRA DE SOUZA FILHO.pdf: 966270 bytes, checksum: ca737a2b0979b32825fa071c0dc153d6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-05-16T12:49:40Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTAÇÃO_DELFINO PEREIRA DE SOUZA FILHO.pdf: 966270 bytes, checksum: ca737a2b0979b32825fa071c0dc153d6 (MD5) / Made available in DSpace on 2018-05-16T12:49:40Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTAÇÃO_DELFINO PEREIRA DE SOUZA FILHO.pdf: 966270 bytes, checksum: ca737a2b0979b32825fa071c0dc153d6 (MD5) Previous issue date: 2017-12-18 / Introduction: Efficient and effective management by means of alternatives of reuse of water in lava jets besides being part of a promising environmental management is also a factor of competitiveness through the economy in the account of monthly water consumption. Planetary water resources are of concern to scientists, environmentalists and rulers as environmental pollution and devastation begin to undergo contingent, unforeseen and more intense behavior and mechanisms based on data known and recorded over a century. Increasingly the media are reporting on regions suffering from water scarcity. The consumption of drinking water or treated in lava jets is a variable that characterizes the need to better understand and use this important and vital natural resource. Objective: general: to examine the environmental issue related to the importance of water for human existence and the way water is managed in car wash stations. Specific: to analyze the value of water use in a rational way, to reduce its waste and to minimize the generation of effluents; to verify the environmental problems related to the process of water use, its treatment and reuse in car wash stations (jet washes); to evaluate environmentally more efficient and effective alternatives for the reuse of water in car wash services; to carry out a diagnosis of the water consumption in the car wash stations located in the housing complexes: Santos Dumont, Hiléia I and Hiléia II. Methodology: Inductive and observational research was carried out in three (3) sets located in the Center-West Zone of Manaus: Santos Dumont Complex, Hiléia I Complex, and Hiléia II Complex. Results: Lava jets 1 and 5 were almost at the same level of consumption; the same was true for car wash stations 2 and 3. PLA 3 spent more water than PLA 1 because of the difference in task execution method. Wash stations 1 and 2 use a bucket with shampoo, water and sponge, in the third procedure. After this procedure the rinse is done. In PLA 1, the two processes are performed concomitantly (shampoo and rinse). In the survey carried out in the 5 washes, there was not only a huge waste of water during the services, but also the bleeding of huge amounts of detergents, greases and oils. Final considerations: In the companies visited, it was verified that there is no work management, there is no technical guidance regarding the material used, nor sensitivity to environmental issues. This fact generates waste. Therefore, there is a lack of sensitivity and respect for the environment, since there are methods and tools available in the market for politically and environmentally correct business attitudes in this market, such as the implementation of the environmental management tool called 3R's and the gravimetric separator. / Introdução: O manejo eficiente e eficaz por meio de alternativas de reutilização da água em lava jatos além de fazer parte de uma gestão ambiental promissora é também fator de competitividade por meio da economia na conta de consumo d’água mensal. Os recursos hídricos planetários preocupam cientistas, ambientalistas e governantes haja vista que a poluição e devastação ambientais começam a sofrer comportamentos e mecanismos contingenciais, imprevistos e mais intensos tendo-se em vista dados conhecidos e registrados no período de um século. Cada vez mais os meios de comunicação informam sobre regiões que sofrem com a escassez de água. O consumo da água potável ou tratada em lava jatos é uma variável que caracteriza muito bem a necessidade de compreender e utilizar melhor esse importante e vital recurso natural. Objetivo: geral: examinar a problemática ambiental referente à importância da água para a existência humana e a forma de gestão da água em postos de lavagem de automóveis. Específicos: analisar o valor do uso da água de forma racional, da redução de seu desperdício e da minimização da geração de efluentes; verificar a problemática ambiental relacionada ao processo de utilização da água, seu tratamento e reuso em postos de lavagem de automóveis (lava jato); avaliar alternativas ambientalmente mais eficientes e eficazes para a reutilização de água nos serviços de lavagem de automóveis; realizar um diagnóstico do consumo de água nos postos de lavagem de automóveis localizados nos conjuntos habitacionais: Santos Dumont, Hiléia I e Hiléia II. Metodologia: As pesquisas indutiva e observacional foram realizadas em 3 (três) conjuntos localizados na Zona Centro-Oeste de Manaus, são eles: Conjunto Santos Dumont, Conjunto Hiléia I e Conjunto Hiléia II. Resultados: Os lava jatos 1 e 5 ficaram quase que no mesmo patamar de consumo; o mesmo aconteceu com os postos de lavagem de automóvel 2 e 3. O PLA 3, gastou mais água em relação ao PLA 1 devido à diferença de método de execução de tarefa. Os postos de lavagens 1 e 2 usam um balde com xampu, água e esponja, no terceiro procedimento, para passar no carro. Após esse procedimento é feito o enxágue. No PLA 1, os dois processos são executados concomitante (xampu e enxague). Na pesquisa realizada nos 5 lava jatos, verificou-se não só um enorme desperdício de água durante os serviços, mas também a sangria de quantidades descomunais de detergentes, graxas e óleos. Considerações finais: Nas empresas visitadas, verificou-se que não há gestão do trabalho, não há orientação técnica quanto ao material utilizado, e nem sensibilidade para questão ambiental. Esse fato gera desperdício. Falta, portanto, sensibilidade e respeito ao meio ambiente, haja vista que existem métodos e ferramentas disponíveis no mercado para atitudes empresariais política e ambientalmente corretas nesse mercado, tal como a implantação da ferramenta de gestão ambiental denominada de 3R’s e o separador gravimétrico.