Browsing Earth and Space Sciences by Title
Now showing items 30-49 of 120
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Field evidence for substrate entrainment by pyroclastic density currents and its effect on downstream dynamics at Mount St Helens, Washington (USA)
(2014-02-24)Despite recent advances in the study of pyroclastic density current (PDC) dynamics, several fundamental aspects of the behavior of these hazardous currents remain poorly understood. Perhaps two of the more significant gaps ... -
From Earth to exoplanets: Quantifying atmospheric biosignatures and biogeochemical controls on habitability
It will soon be possible to determine the atmospheric composition of potentially habitable planets around other stars via astronomical observations. This raises the exciting possibility of detecting life remotely from its ... -
From Subduction to Collision: Sedimentary Basin Constraints on Timescales and Geodynamic Drivers
The Tethyan orogenic belt extends from the western Mediterranean to southeast Asia and the exposed rocks and landscapes present today are records of multiple orogenic events. The most recent, the Alpine-Himalayan orogeny, ... -
Fundamental controls on triple oxygen-isotope ratios in Antarctic precipitation and ice cores
Stable isotope ratios of water (δD and δ18O) in polar precipitation and ice cores have long been used to study past climate variations and the hydrological cycle. Recently-developed methods permit the precise measurement ... -
Geometry and Visualization of Folds
Reconstructing the geometry of geologic folds, and subsequently expressing this geometry visually, are necessary for understanding the kinematic and mechanical properties of folds. Novel technology for acquiring 3D geometric ... -
Geomorphic and Atmospheric Investigations on the Habitability of Past and Present Mars
While the current surface of Mars is viewed to be inhospitable to life as we know it, past Mars may have harbored habitable environments though the extent and duration of such environment is still unclear. There are several ... -
Glacier erosion at convergent margins: a numerical and field study in the Chugach-St. Elias Mountains of South Alaska
(2013-07-25)Glacier erosion at convergent margins: a numerical and field study in the Chugach-St. Elias Mountains of South Alaska The Saint Elias range of South Alaska is known for its rapid erosion and uplift (order of 1 cm/yr), ... -
Glaciers, erosion and climate change in the Himalaya and St. Elias Range, SE Alaska
The important roles of glaciers in topographic evolution, relief development, and sediment production are well recognized but understanding remains rather limited largely because of the inherent complexity of glacial erosion ... -
Greenland outlet glacier behavior during the 21st century: Understanding velocities and environmental factors
Outlet glacier ice dynamics, including ice-flow speed, play a key role in determining Greenland Ice Sheet mass loss, which is a significant contributor to global sea-level rise. Mass loss from the Greenland Ice Sheet ... -
Hillslope erosion and weathering rates in Earth's most rapidly uplifting mountains
(2014-02-24)Knowledge of hillslope erosion rates and processes is necessary for understanding landscape response to tectonic and climatic forcing and for determining the degree to which mountains regulate biogeochemical cycles and ... -
Hydrated silica on Mars: Global comparison and in-depth analysis at Antoniadi Crater
(2012-09-13)Hydrated silica is found in a variety of Martian deposits within suites of minerals that indicate aqueous alteration, mostly because hydrated silica forms easily in different environments. Because of its relative ubiquity ... -
Imaging northern Cascadia wave speed structure and slow slip
I calculate tremor source amplitudes for the northern Cascadia episodic tremor and slip (ETS) events from 2007-2010 and find they exhibit similar spatiotemporal patterns of radiated energy from tectonic tremor. In the ... -
Implications and Limitations of Tremor as a Proxy for Slow Slip
This thesis seeks to integrate geodetic and seismic observations to explore the relationship between tremor and slow slip on subduction zones. In particular, I evaluate the one-to-one relationship of tremor and slip in ... -
Innovations in pulsed plasma thrusters to enable CubeSat science missions
CubeSats and other small satellites in the 3-25 kg range are increasingly able to conduct meaningful science through advances in technology and miniaturization. However, much of the proposed science requires satellite ... -
Investigating the drivers of glacier retreat in West Antarctica using proxy-data assimilation and numerical modeling
Outlet glaciers in West Antarctica are rapidly retreating and contributing to sea level rise. Ice loss is primarily occurring via wind-driven incursions of warm circumpolar deep water melting the ice shelves that buttress ... -
Investigating the effects of <italic>Bacillus subtilis</italic> endospore surface reactivity on low-temperature aqueous geochemical systems
Microbes are a ubiquitous component in water-rock systems including ground and surface waters, soils, mid-ocean ridge hydrothermal systems, and deep sedimentary basins. Microbial envelopes provide complex organic surfaces ... -
Investigating the evolution of fault scarps in jointed volcanic rock through field evidence, morphometric techniques and novel methods
The morphology of fault scarps in jointed volcanic rock records information on the tectonics, volcanism and geomorphology of a region. The evolution of scarp form has been modeled to extract information varying from the ... -
Investigating the interior of West Antarctica with light, radar, and electrical conductance
(2014-02-24)Ice sheets play an important role in both the modern climate and in past variations of Earth's history. Our understanding of ice sheets has been limited by few observations until recent advances in technology, notably air ... -
Investigating the roles of ice dynamics and climate on polar near-surface processes
Understanding processes in the snow and firn are important for studies of ice dynamics, ice-sheet mass balance, glacial hydrology, and ice-core interpretation. In this dissertation, I use a combination of modeling, geophysical ... -
Investigations of glacier terminus changes on weekly to decadal time scales
Glacier retreat and mass loss are contributing to global sea-level rise and environmental change. One method to improve our understanding of how glaciers affect local and global environments is to measure historical and ...