Who: Peter Flemings of the University of TexasDate: April 4, 2008, at 4:00 p.m.Location: Weyandt Hall, Room 107, Indiana University of PennsylvaniaContact: For further information regarding this event, please contact the Geoscience Department at 724-357-2379 or by e-mail to firstname.lastname@example.org.
The Geoscience Department seminar to be presented by Peter Flemings of the University of Texas, Austin, will discuss how sedimentation, combined with changes in climate and the associated sea-level change, can induce large submarine landslides.
When fine-grained sediments are deposited unevenly above a confined aquifer, flow is driven laterally, effective stresses above the aquifer are reduced, and slope failure can occur. This process is like stepping on a water balloon: rapid sedimentation acting as the “heel” drives water toward the “toe,” where its high pressure causes large blocks of sediment to slide downhill. Integrated Ocean Drilling Program (IODP) Expedition 308, named “Gulf of Mexico Hydrogeology,” examined pore pressure, fluid flow, and slope stability at the mouth of the Mississippi delta—one of the great sediment dumps of the world. We found an abrupt jump in pressure immediately beneath a zone of large submarine landslides that span hundreds of square miles and conclude that sedimentation, driven by changes in climate and associated sea-level change, generates pressure, drives fluid flow, and induces landslides. In the Pleistocene, during sea level low stands, this process may have set loose significant submarine landslides around the world. Ultimately these studies may allow us to predict in what locations around the world submarine landslides are more likely—and hence what structures and local populations are at greater risk.
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