Search
Now showing items 1-10 of 120
The Role of Corals on Tsunami Dynamics in an Island Setting: A Case Study of Tutuila Island
On September 29, 2009 at 17:48 UTC, an Mw = 8.1 earthquake in the Tonga Trench generated a tsunami that caused heavy damage across Samoa, American Samoa, and Tonga. One of the worst localities hit was the volcanic island of Tutuila in American Samoa. Tutuila Island, located 250 km from earthquake epicenter, experienced tsunami ...
The Complexity of Arc Magmatism: A Geochemical Investigation of Crustal Processes Beneath a Highly Productive Volcanic Center, Kamchatka, Russia
(University of Washington Graduate School, 2012)
Understanding crustal modification of magmas in volcanic arcs is a fundamental problem of igneous petrology and geochemistry. This dissertation examines the role of crustal processes including crustal assimilation, magma mixing, magma differentiation, and volatile transport in generating erupted magmas from four volcanic ...
Melt-Triggered Seismic Response in Hydraulically-Active Polar Ice: Observations and Methods
(2014-02-24)
Glacier ice responds to environmental forcing through changes in its sliding speed and mass balance. While these changes often occur on daily time scales or longer, they are initiated by brittle deformation events that establish hydrological pathways in hours or seconds and allow meltwater access to englacial or subglacial ...
On the origin of Umtanum Ridge: kinematics of Neogene slip
(2014-04-30)
Constraining the geometry of active faults is an important step in determining accurate estimates of regional seismic hazard. Where subsurface data are lacking, the shape of hanging wall folds can be used to interpret fault geometry at depth. In order to better understand the seismic hazard posed by the Yakima folds in central ...
The influence of meltwater on the thermal structure and flow of the Greenland Ice Sheet
As the climate has warmed over the past decades, the amount of melt on the Greenland Ice Sheet has increased, and areas higher on the ice sheet have begun to melt regularly. This increase in melt has been hypothesized to enhance ice flow in myriad ways, including through basal lubrication and englacial refreezing. By ...
The Plasma Physics Processes that Drive Ring Current Enhancements during Geomagnetic Storms and Substorms
(2012-09-13)
Geomagnetic storms result when energetic particles of solar and ionospheric origin fill Earth's inner magnetosphere and create a strong westward current, known as the ring current. This dissertation presents results from investigating the plasma dynamics that contribute to the development of Earth's ring current from ionospheric ...
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 dominated by two swarm sequences in January and February 2005 in the vicinity of the Endeavour overlapping ...
Experimental Investigation into the Enhanced Diamagnetic Perturbations and Electric Currents Downstream of the High Power Helicon Plasma Thruster
(2013-11-14)
The high power helicon (HPH) is a compact plasma source that can generate downstream densities of 10<super>17</super>-10<super>18</super> m<super>-3</super> and directed ion energies of 50-70 eV, without the need for grids that can corrode with use or requiring a larger engine diameter. Generating a quasi-neutral plasma beam ...
Underwater Acoustic Propagation in the Philippine Sea: Intensity Fluctuations
(2013-11-14)
In the spring of 2009, broadband transmissions from a ship-suspended source with a 284 Hz center frequency were received on a moored and navigated vertical array of hydrophones over a range of 107 km in the Philippine Sea. During a 60-hour period over 19 000 transmissions were carried out. The observed wavefront arrival ...
Uncertainty and Resolution in Full-Waveform, Continuous, Geoacoustic Inversion
(2013-11-14)
The ocean geoacoustic inverse problem is the estimation of physical properties of the ocean bottom from a set of acoustic receptions in the water column. The problem is considered in the context of equipment and spatial scales relevant to naval sonar. This dissertation explores uncertainty, resolution, and regularization ...