Record Details
A sedimentary and geophysical investigation offshore of Sumatra : subduction zone earthquakes, ground motions, and submarine landslides
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | A sedimentary and geophysical investigation offshore of Sumatra : subduction zone earthquakes, ground motions, and submarine landslides |
| Names |
Patton, Jason Robert
(creator) Goldfinger, Chris (advisor) |
| Date Issued | 2014-01-09 (iso8601) |
| Note | Graduation date: 2014 |
| Abstract | Subduction zone earthquake and tsunami hazards affect tens of millions worldwide and the recurrence of these disasters can be evaluated with paleoseismic techniques, because earthquake cycles (and their supercycles) typically span many millennia. In these three chapters, I discuss a suite of analyses I use to evaluate the sedimentary record of earthquakes as sampled in cores collected by the authors on the R/V Roger Revelle in 2007 offshore Sumatra, cruise RR0705, aka KNOX05RR. In the first chapter I discuss the mid- to late-Holocene recurrence of earthquakes in the region of the 2004 Sumatra-Andaman subduction zone earthquake. I estimate that the early Holocene to historic recurrence of turbidity current triggering earthquakes in the region of the 2004 Sumatra-Andaman subduction zone earthquake to be 260 ± 160 calendar years. I identify the uppermost turbidite in fifteen cores to have been deposited as a result of strong ground shaking from this 2004 earthquake. In the second chapter I compare and contrast the physiographic control of seismoturbidite deposition along the continental margins of the Sumatra-Andaman and Cascadia subduction zones. Cascadia’s margin is dominated by glacial cycle constructed pathways which promote turbidity current flows for large distances. Sumatra margin pathways do not inherit analogous sedimentary systems, so turbidity currents and their deposits are more localized. Finally, I discuss slope stability and earthquake ground motions along the continental margin offshore the coast of Sumatra. In this third chapter I relate the potential for slope instability with core stratigraphy in slope basin cores along the Sumatra-Andaman subduction zone, both for generic earthquakes and for the 2004 earthquake. Using 2-D profile factor of safety analyses, I estimate that slopes become unstable when a seismic load of <0.2 g is imparted. Using infinite slope factor of safety analyses, I conclude that turbidity currents are triggered by earthquakes of at least magnitude M = 7. For the 2004 Sumatra-Andaman subduction zone earthquake, I find that the shaking intensity from ground motion does not explain the thickness of turbidites, which must be explained by other factors like site effects, site geomorphology, or source proximity. |
| Genre | Thesis/Dissertation |
| Access Condition | http://creativecommons.org/licenses/by-nd/3.0/us/ |
| Topic | earthquake |
| Identifier | http://hdl.handle.net/1957/45785 |
