Thesis--Columbia University. / Bibliography: leaves 121-124.

Thesis--University of Wisconsin. / Vita. Includes bibliographical references (leaves 130-137).

Thesis (Ph. D.)--University of Idaho, 2006. / Abstract. "May 2006." Includes bibliographical references. Also available online in PDF format.

Thesis (M.Sc.)--Saint Mary's University, 2008. / Includes abstract. Supervisor: Georgia Pe-Piper. Includes bibliographical references (leaves 141-148).

No description available.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 162-173). Also available for download via the World Wide Web; free to University of Oregon users.

Ash-flow tuff (ignimbrite) is a general term indicating consolidated deposits of volcanic ash flow; a flow of a mixture of gas and pyroclastic materials as products of explosive volcano eruptions (Smith, 1960). Two different ash-flow tuffs are studied in this research: 1. Topopah Spring Tuff at Yucca Mountain, Nevada and 2. the Bandelier Tuff at Pajarito Plateau, New Mexico. Various dynamic test parameters (e.g. confining pressure, shearing strain, etc) were studied with two existing devices: (1) the combined resonant column and torsional shear (RCTS) device, and (2) the free-free, unconfined, resonant column (URC) device. The effects of these parameters are evaluated for two different types of ash-flow tuffs. In addition, a Large Resonant Column (LgRC) device was developed and used to test the some tuffs from Yucca Mountain at larger strain amplitudes than possible with the RCTS and URC devices. Relationships between the linear and nonlinear dynamic properties and lithostratigraphic features were further investigated. Finally, potential problems related to sample disturbance and specimen size are considered based on comparisons of small-strain shear wave velocity (VS) values measured in the laboratory and in the field. / text

A three-dimensional stochastic numerical inverse model has been developed for characterizing the properties of unsaturated fractured medium through analysis of singleand cross-hole pneumatic tests. Over 270 single-hole [Guzman et al., 1996] and 44 cross-hole pneumatic tests [Illman et al., 1998; Inman, 1999] were conducted in 16 shallow vertical and slanted boreholes in unsaturated fractured tuffs at the Apache Leap Research Site (ALRS), Arizona. The single-hole tests were interpreted through steady-state [Guzman et al., 1996] and transient [Illman and Neuman, 2000b] analytical methods. The cross-hole tests were interpreted by analytical type-curves [Illman and Neuman, 2000a]. I describe a geostatistical analysis of the steady-state single-hole data, and numerical inversion of transient single-hole and cross-hole data. The geostatistical analysis of single-hole steady-state data yields information about the spatial structure of air permeabilities on a nominal scale of 1 m. The numerical inverse analysis of transient pneumatic test data is based on the assumption of isothermal single-phase airflow through a locally isotropic, uniform or non-uniform continuum. The stochastic inverse model is based on the geostatistical pilot point method of parameterization [de Marsily, 1978], coupled with a maximum likelihood definition of the inverse problem [Carrera and Neuman, 1986a]. The model combines a finite-volume flow simulator, FEHM [Zyvoloski et al., 1997], an automatic mesh generator, X3D [Trease et al., 1996], a parallelized version of an automatic parameter estimator, PEST [Doherty et al., 1994], and a geostatistical code, GSTAT [Pebesma and Wesseling, 1998]. The model accounts directly for the ability of all borehole intervals to store and conduct air through the system; solves the airflow equations in their original nonlinear form accounting for the dependence of air compressibility on absolute air pressure; can, in principle, account for atmospheric pressure fluctuations at the soil surface; provides kriged estimates of spatial variations in air permeability and air-filled porosity throughout the tested fractured rock volume; and is applied simultaneously to pressure data from multiple borehole intervals as well as to multiple cross-hole tests. The latter amounts to three-dimensional stochastic imaging, or pneumatic tomography, of the rock as proposed by Neuman [1987] in connection with cross-hole hydraulic tests in fractured crystalline rocks near Oracle, Arizona. The model is run in parallel on a supercomputer using 32 processors. Numerical inversion of single-hole pneumatic tests allows interpreting multiple injection-step and recovery data simultaneously, and yields information about air permeability, air-filled porosity, and dimensionless borehole storage coefficient. Some of this cannot be accomplished with type-curves [Inman and Neuman, 2000b]. Air permeability values obtained by my inverse method agree well with those obtained by steady-state and type-curve analyses. Both stochastic inverse analysis of cross-hole data and geostatistical analysis of single-hole data, yield similar geometric mean and similar spatial pattern of air permeability. However, I observe a scale effect in both air permeability and air-filled porosity when I analyze cross-hole pressure records from individual monitoring intervals one by one, while treating the medium as being uniform; both pneumatic parameters have a geometric mean that is larger, and a variance that is smaller, than those obtained by simultaneous stochastic analysis of multiple pressure records. Overall, my analysis suggests that (a) pneumatic pressure behavior of unsaturated fractured tuffs at the ALRS can be interpreted by treating the rock as a continuum on scales ranging from meters to tens of meters; (b) this continuum is representative primarily of interconnected fractures; (c) its pneumatic properties nevertheless correlate poorly with fracture density; and (d) air permeability and air-filled porosity exhibit multiscale random variations in space.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 174-181).

The Wah Wah Springs Tuff (30.0 Ma) is one of several very large volume ash-flow tuffs (>3200 km³ of erupted magma) that were emplaced near the peak of the flare-up of activity in the Great Basin ignimbrite province of western North America. It can be characterized as a "monotonous intermediate" ignimbrite because of its intermediate concentrations of silica (~63 to ~70 wt. %), apparent uniform chemical and mineralogical characteristics, and crystal-rich nature (32 ± 10 % phenocrysts on a dense rock basis). The major phase assemblage found throughout deposit is similar to other monotonous intermediates with a few exceptions (pl > hnbl > bio, qtz >> cpx, opx > mt, ilm, ap, zcn, and po). Based on experiments on the monotonous intermediate Fish Canyon Tuff (Johnson & Rutherford, 1989a) and this phase assemblage, the Wah Wah Springs magma equilibrated between 775°C – 800°C. One hornblende-plagioclase thermometer with or without quartz (Holland & Blundy, 1994) and one Fe-Ti oxides thermometer (Anderson et al., 1993) most consistently yield temperatures within this range. The Fe-Ti oxides oxy barometer (Anderson et al., 1993) yield fO2 estimates 2 – 3 log units above the quartz-fayalite-magnetite buffer. The Al-in-hornblende geobarometer (Johnson & Rutherford 1989b) indicates pressures between 2.0 and 2.5 kb. Detailed compositional profiles across hornblende and plagioclase grains help constrain how intensive parameters changed during the evolution of the magma shortly before eruption. Plagioclase in the Wah Wah Springs displays oscillatory zonation with overall normal zonation (a maximum change of about An5 from core to rim). Hornblende is also zoned in Al2O3 and TiO2 which typically decrease as much as 2.5 wt. % and 1 wt. % respectively from core to rim. These zoning patterns are consistent with a decrease of temperature from core to rim that accompanied progressive crystallization of a large body of magma that closely approached equilibrium. These conditions in the parent magma for the Wah Wah Springs differ from interpretations of mineral compositions in the Fish Canyon Tuff which led Bachman et al., (2002) to propose that the near solidus magma body was "rejuvenated" or reheated immediately prior to eruption. This model cannot be applied to the Wah Wah Springs. Rather, the Wah Wah Springs magma appears to have been cooling and crystallizing prior to eruption.