Physical Sciences and Mathematics Commons^™

Surface Wave Inversion Of The Upper Mantle Velocity Structure In The Ross Sea Region, Western Antarctica, James D. Rinke

All Master's Theses

The Ross Sea in Western Antarctica is the locale of several extensional basins formed during Cretaceous to Paleogene rifting. Several seismic studies along the Transantarctic Mountains and Victoria Land Basin’s Terror Rift have shown a general pattern of fast seismic velocities in East Antarctica and slow seismic velocities in West Antarctica. This study focuses on the mantle seismic velocity structure of the West Antarctic Rift System in the Ross Embayment and adjacent craton and Transantarctic Mountains to further refine details of the velocity structure.

Teleseismic events were selected to satisfy the two-station great-circle-path method between 5 Polar Earth Observing Network …

Fluid Budget Of Metasedimentary Rocks From A Tertiary Accretionary Prism And Connections To Seismicity, Olympic Peninsula, Northwest Washington State, Holly Makena Macfadden Rotman

All Master's Theses

Metamorphic dehydration reactions and fluid movement in accretionary prisms have been linked to the recently discovered episodic tremor and slip (ETS) earthquake events along subduction zones, but prior studies lack the detail to effectively test the hypothesis that fluid flow triggers ETS events. I conducted field work along a 52.5 km transect on the Olympic Peninsula metasedimentary accretionary prism of the Cascadia subduction zone, and collected approximately 40 representative samples of sandstone and mudrock that were buried to 6–15 km. This depth range intersects the 10–50 km depth range of ETS events. My objectives are to quantify the water flow …

Energy Budget Analysis Of Slow-Slip Tremor Events Along The Cascadia Subduction Zone Using Continuous Gps Array Data, James Steven Chapman

All Master's Theses

Seismic hazards poised to cities by subduction zones are strongly controlled by fault slip along the deeper extent of the two plate interaction closest to population densities. In Cascadia, where Mw=9 size events are known to occur from a variety of sources, modeling of leveling data has suggested that the region of maximum slip lies well offshore and diminishes rapidly inland. However, over two dozen slow slip distributions have been imaged using Global Positioning System (GPS) along the lower reaches of the northern Cascadia locked zone between 30 and 40 km in depth. Averaged over many episodic tremor and slip …

The 2004 And 1861 Tsunami Deposits On Simeulue Island, Western Sumatra, Katherine Frances Whitlow

All Master's Theses

Megathrust earthquakes and associated tsunamis along the subduction zone along western Sumatra represent a significant seismic hazard that is not well understood. I present the results of mapping, paleoseimologic, and geochronologic studies of tsunami deposits exposed on Simeulue Island, western Sumatra, to document the timing of past tsunamis. Three field sites were targeted to conduct these studies: Inor, Busong Bay, and Langi Bay. Stratigraphic relationships, geochronologic data, and grain size analyses from these field sites show evidence of a tsunami that occurred in 1861 following a Mw ~8.5 earthquake. A wood fragment collected from an excavation at Inor yielded an …

Seismic Constraints On Slow Slip Events Within The Cascadia Subduction Zone, Ana Cristina Aguiar

All Master's Theses

Reanalysis of geodetic GPS time series from the Cascadia subduction zone have revealed at least 30 resolvable slow slip events along the megathrust, ranging from northern California to southern British Columbia, since 1997. Many of the smaller and more recent events are barely resolvable with GPS, but stand out clearly as tremor sequences. Since tremor bursts lasting less than 10-seconds are often visible across multiple stations, they offer the highest resolution for studying moment release through time. To test the hypothesis that tremor and transient deformation are two manifestations of the same faulting process, and to quantify the relative contribution …