Thesis (Ph. D.)--University of Oregon, 2003. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 163-187). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (M.S.)--University of Utah, 2000. / "FY00-246." Title from web page (viewed Nov. 13, 2003). Includes bibliographical references (p. [118]-122). Also available in print version.

Thesis (M.A.)--University of Nevada, Reno, 2008. / "August, 2008." Includes bibliographical references (leaves 126-136). Online version available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 1997. / Includes bibliographical references (leaves [258]-290).

Thesis (M.A.)--Brigham Young University. Dept. of Anthropology, 2007. / Includes bibliographical references (p. 135-144).

Thesis (Ph. D.)--University of Oregon, 2003. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 163-187). Also available for download via the World Wide Web; free to University of Oregon users.

abstract: Earthquake faulting and the dynamics of subducting lithosphere are among the frontiers of geophysics. Exploring the nature, cause, and implications of geophysical phenomena requires multidisciplinary investigations focused at a range of spatial scales. Within this dissertation, I present studies of micro-scale processes using observational seismology and experimental mineral physics to provide important constraints on models for a range of large-scale geophysical phenomena within the crust and mantle. The Great Basin (GB) in the western U.S. is part of the diffuse North American-Pacific plate boundary. The interior of the GB occasionally produces large earthquakes, yet the current distribution of regional seismic networks poorly samples it. The EarthScope USArray Transportable Array provides unprecedented station density and data quality for the central GB. I use this dataset to develop an earthquake catalog for the region that is complete to M 1.5. The catalog contains small-magnitude seismicity throughout the interior of the GB. The spatial distribution of earthquakes is consistent with recent regional geodetic studies, confirming that the interior of the GB is actively deforming everywhere and all the time. Additionally, improved event detection thresholds reveal that swarms of temporally-clustered repeating earthquakes occur throughout the GB. The swarms are not associated with active volcanism or other swarm triggering mechanisms, and therefore, may represent a common fault behavior. Enstatite (Mg,Fe)SiO3 is the second most abundant mineral within subducting lithosphere. Previous studies suggest that metastable enstatite within subducting slabs may persist to the base of the mantle transition zone (MTZ) before transforming to high-pressure polymorphs. The metastable persistence of enstatite has been proposed as a potential cause for both deep-focus earthquakes and the stagnation of slabs at the base of the MTZ. I show that natural Al- and Fe-bearing enstatite reacts more readily than previous studies and by multiple transformation mechanisms at conditions as low as 1200°C and 18 GPa. Metastable enstatite is thus unlikely to survive to the base of the MTZ. Additionally, coherent growth of akimotoite and other high-pressure phases along polysynthetic twin boundaries provides a mechanism for the inheritance of crystallographic preferred orientation from previously deformed enstatite-bearing rocks within subducting slabs. / Dissertation/Thesis / Great Basin Seismicity from 2004 to 2013 (event data) / Great Basin Seismicity from 2004 to 2013 (Google Earth) / Doctoral Dissertation Geological Sciences 2015

<p>In arid regions, springs are important in many aspects of society due to the scarcity of surface water features. In the Great Basin of the United States, desert springs support the majority of regional biodiversity and are critical for supporting rare, threatened, and endangered organisms. Despite their importance, there are numerous threats to desert springs, with the most ubiquitous being climate change. In contrast to many studies examining potential metrics to describe the vulnerability of streams, wetlands and other surface water features to the effects of climate change, springs are often overlooked. Part of the knowledge gap stems from the complexity of springflow generation and the rarely field-tested connection between groundwater response time and groundwater residence time.</p> <p> This dissertation tests, in a systematic way, different metrics that may help define criteria to evaluate whether a spring is likely to persist or desiccate with increasing regional hydrologic stress due to climate change. Field data was collected over a 4-year period from >80 springs across the topographically and geologically heterogeneous terrain of the southern Great Basin. </p> <p>Throughout this dissertation, I use a variety of different tools (e.g., remote sensing, environmental tracers, geospatial analysis) to “attack” this complicated problem from different angles. I begin by examining factors indicative of hydrogeologic resistance to major drought. After finding a connection between groundwater residence time and hydrogeologic resistance, I examine other factors (e.g., geochemical, topographic, ecological, variability) that are related to groundwater residence time and also identify where these relationships fail. </p>

Groundwater levels over northern Utah have undergone a declining trend since the 1960’s. This trend has made apparent the need to understand the relationship between climate and groundwater resources. Such necessary information is already in dire need in places such as California. At the close of 2013, California had experienced its driest year in recorded history, with severe drought continuing for the foreseeable future. Utah is the second driest state in the U.S., and therefore has been paying close attention to California’s current water crises. Water resource projections may prove to be one of the most vital pieces of information toward securing adequate water for those who are currently enduring such water shortages. In order to accomplish the initial research necessary for developing a fundable proposal, we requested support from the Utah State University Research Catalyst Grant to (a) evaluate a state-of-the-art climate model (its ability to assess groundwater) against statewide groundwater wells and operational groundwater models, (b) reduce climate model uncertainties, (c) conduct a study in the form of observational well site evaluations, and (d) develop strategies to effectively disseminate information on Utah’s future groundwater budget to water managers and policy makers. This research is now fully funded externally by the Bureau of Reclamation.

This study was undertaken to determine which characteristics, if any , distinguish exit from active milk producers; why producers exit from the industry; what happens to those resources formerly used in the dairy industry; the predictability of a producer either increasing or decreasing in size. This study encompassed the milk producers in the Great Basin Federal Milk Market Area which is the central and northern part of Utah. It was not possible to determine any characteristics which would distinguish the exit from the active producers. All of the sample producers sold most of their cows. A large percentage kept their land and continued to operate it. Much of the equipment was kept by the producer. The Markov Chain analysis indicated that dairy farm numbers will decrease: however, the size of the active farms will increase.