xi, 114 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Different models have been proposed for the "drumbeat" earthquakes that
accompanied recent eruptive behavior at Mount St. Helens. Debate continues as to
whether seismicity is related to brittle failure during the extrusion of solid dacite spines or
is the result of hydrothermal fluids interacting with a crack buried in the volcanic edifice.
My model predictions of steady-state conduit flow confirm the strong control that
degassing exerts on eruptive behavior. I discuss the necessary role of degassing for
extruded material to attain the high density (low vesicularity) of the observed spine
material and discuss the implications for generating seismicity. A brittle-failure source of
seismicity requires that the gouge elastic properties accommodate some strain, since the
magma compressibility in the upper conduit is too low to do so on its own. I also report on a novel method for generating high-resolution digital elevation models of fault surface
textures. / Committee in Charge: Dr. Alan Rempel, Chair;
Dr. Katharine Cashman;
Dr. David Schmidt
| Identifer | oai:union.ndltd.org:uoregon.edu/oai:scholarsbank.uoregon.edu:1794/10026 |
| Date | 09 1900 |
| Creators | Schneider, Andrew Daniel, 1982- |
| Publisher | University of Oregon |
| Source Sets | University of Oregon |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Relation | University of Oregon theses, Dept. of Geological Sciences, M.S., 2009; |
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