Browsing Earth and Space Sciences by Title
Now showing items 74-93 of 120
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Quantifying changes in climate and surface elevation of polar ice sheets during the last glacial-interglacial transition
This dissertation describes three research projects investigating changes in polar climate and the ice sheets during the last deglaciation. The first project, Chapter 2, reconstructs the past 20,000 years of Greenland ... -
Quantifying ice-shelf basal melt and ice-stream dynamics using high-resolution DEM and GPS time series
This dissertation describes methods to generate high-resolution digital elevation models (DEMs) of the Earth's ice sheets, and combines these observations with in situ GPS measurements to study basal melting beneath the ... -
Quaternary glaciation in Central Asia
The mountain ranges in Central Asia were heavily glaciated during the Quaternary Period. The relative magnitudes of paleoglaciers varied spatially and temporally. The chronology of glacial standstills was established from ... -
Quaternary grounding-line fluctuations in Antarctica
The West Antarctic Ice Sheet may be prone to rapid collapse under climates warmer than today due to a dynamic instability at the grounding line, where the ice sheet goes afloat over seawater. However, there is to-date no ... -
Re-Evaluating the Late Devonian Mass Extinction: A Geochemical Investigation of the Relationship between Carbon Isotope Fluctuations, Faunal Turnover, and Paleoenvironmental Change Recorded in Upper Devonian Carbonates of the Lennard Shelf, Western Australia
The primary goal of this dissertation is to increase understanding of the so-called Late Devonian mass extinction through the use of stable isotope geochemistry. Despite decades of research, the timing, cause(s), and extent ... -
Relationships between climate and geophysical processes: what climate histories can be inferred from glaciers, lakes, and ice streams?
This dissertation aims to characterize the present and future variability of the Earth's climate by putting it in the context of past variations in climate. Herein I explore how the spatial and temporal fluctuations of ... -
Seismic Structure and Crustal Accretion Along an Intermediate-rate Mid-Ocean Ridge Segment
(2013-11-14)Epicenters and magnitudes for 36,523 earthquakes recorded along the Endeavour segment between August 2003 and October 2006 are automatically determined using a local ocean-bottom seismometer (OBS) network. The catalog is ... -
Seismic Study of Tremor, Deep Long-Period Earthquakes, and Basin Amplification of Ground Motion
In this thesis, we use seismic data and seismological tools to investigate three topics, (1) triggering between slow slip (tremor as proxy) and nearby small earthquakes, (2) mechanisms of deep-long period earthquakes beneath ... -
Sensing impacts to the Earth-ionosphere waveguide from terrestrial and space weather
The Earth's lower ionosphere forms the lower-altitude limit of space plasma near the Earth, coexisting with the neutral mesosphere-lower thermosphere at 60-150 km altitude. In-situ measurements of this region are made ... -
Slow Earthquakes: Tremor, Low-frequency Earthquakes and Slow Slip Events
The focus of this thesis is slow earthquakes, that is earthquake-like events that release energy over a period of hours to months, rather than the seconds to minutes characteristic of a typical earthquake. Slow slip events ... -
Source, propagation, and effects of lightning in the Earth-ionosphere system
The capabilities of the World Wide Lightning Location Network (WWLLN) are expanded to enable research of the source, propagation, and effects of lightning in the Earth-ionosphere system. The main expansion of the network ... -
Spectroscopic Analysis of Various Phases of Water with an Intrinsic Near-Infrared Optical Sensor System
(2013-07-25)Results and analysis are reported for near-infrared spectra obtained using an intrinsic optical sensor system. An experimental facility was designed to integrate fiber optic cables with an FTIR spectrometer. Wavelength-dependent ... -
Stability and Uncertainty of Ice-Sheet Crystal Fabrics
Ice crystal orientation fabric has a large effect on polycrystalline ice flow. In this thesis, I explore uncertainty of ice fabric measurements, and the related question of stability of ice crystal fabrics and anisotropic ... -
Stable Isotopes in Unstable Times: A geochemical investigation of the end Cretaceous mass extinction
This primary goal of this dissertation is to increase understanding of the end Cretaceous (or Cretaceous - Paleogene or K-Pg) mass extinction through the use of light stable isotope geochemistry. These studies attempt to ... -
Strath terrace formation: the influence of rock type, climate, and humans
Strath terraces record cycles of bedrock river incision and planation, and thus reflect how mountainous landscapes evolved in response to changing climate, tectonics, rock type, and other forcings. Previous work has used ... -
Structural controls and diagenetic conditions associated with fluid migration on the Moab Fault, UT
Faults and fault zones can have strong effects on fluid migration within the Earth’s crust, with important implications for resource management and earthquake hazards. The research presented within this dissertation addresses ... -
Surficial Seismology: Landslides, Glaciers, and Volcanoes in the Pacific Northwest through a Seismic Lens
(2014-02-24)The following work is focused on the use of both traditional and novel seismological tools, combined with concepts from other disciplines, to investigate shallow seismic sources and hazards. The study area is the dynamic ... -
Tectonics as recorded by thermochronometry, deformed datums, and submarine landscapes in western North America
Since the Mesozoic, the west coast of North America has experienced near continuous right-lateral shear. Over this time, a series of exotic crustal terranes accreted to and translated along the expanding westward edge of ... -
Terrestrial Paleoclimate of the Cenozoic: Insights from and Developments of the Soil Carbonate Clumped Isotope Thermometer
Land temperature at the surface of the Earth is a first-order parameter used to describe climate, but reliable and widespread measurements of this basic parameter through geologic time has eluded geochemists and geologists ... -
Testing the theory of radiation belt electron loss by hiss and electromagnetic ion cyclotron waves
Hiss, chorus and electromagnetic ion cyclotron waves (EMIC wave) are three major wave modes that are widely investigated and included in the radiation belt electron models to explain electron precipitation. The quasi-linear ...