February 2008
- FRIDAY, February 1, 2008, Tom Casadevall
USGS Denver
"Lusi Mud Volcano, Indonesia"
Time yet to be arranged
- Wednesday, 9:00 a.m., February 6, 2008, Simon Carn
University of Maryland
"TBA"
- February 14, 2008, Tom Sisson
USGS Menlo Park
"Crustal structure of arc magmatic systems"
- February 21, 2008
no talk
- Friday, 9:30 a.m., February 29, 2008, Jim Rice
Harvard University
"Aseismic transients in subduction zones: What physical basis?"
|
Abstract: Recurrent aseismic deformation transients, sometimes accompanied by deep non-volcanic tremor, have been observed in several shallow subduction zones. They pose significant questions as to their origin, and to the nature of interseismic loading of the locked seismogenic zone. In work with, and principally by, Yajing Liu (now at Princeton) on modeling subduction earthquake sequences, we found that aseismic transients emerge as a natural outcome of the rate- and state friction processes as revealed in lab fault-sliding experiments. When the fluid pore pressure is near-lithostatic (effective stress, ~ 1-5 MPa) around and down-dip from the velocity-weakening-to-strengthening stability transition, the system exhibits self-sustained short-period (several months to a few years) aseismic oscillations, assuming lab-like values (~ 10-30 microns) of the characteristic slip distance for renewal of the contact population. Evidence that such fluid pressure conditions may actually be present is provided independently by the occurrence of non-volcanic tremors as apparent responses to extremely small (< 0.01 MPa) stress changes, and by petrological constraints on the expected regions of metamorphic dehydration in shallow-dipping subduction zones, such as the northern Cascadia, SW Japan and Guerrero, Mexico. Our modeling predicts that transient sequences can also be triggered by a step-like interseismic stress perturbation on the subduction fault, due to nearby earthquakes, or to pore pressure changes, e.g., during episodes of metamorphic fluid release.
|
March 2008
- March 6, 2008, Eliza Calder
SUNY Buffalo
"TBA"
- March 13, 2008, Roy Hyndman
CANCELLED !!! (it may be re-scheduled at a later date, please check again)
Pacific Geoscience Center
"TBA"
- March 20, 2008, Chuck Wicks
RESCHEDULED to May 12th !!!
USGS Menlo Park
"TBA"
- March 27, 2008, Joe Dufek
TIME CHANGE to 2pm !!!
University of California, Berkley
"Self-organization in pyroclastic density currents: Integrating multi-scale observations with macroscopic models of explosive volcanic activity"
April 2008
- April 3, 2008, Nicole Lautze
USGS Menlo Park
"TBA"
- April 10, 2008, Charlie Bacon
USGS Menlo Park
"TBA"
- April 17, 2008, Michael Hutnak
RESCHEDULED to May 22th !!!
USGS Menlo Park
"Numerical Simulations of Hydrothermal Fluid Flow and Caldera Deformation: Effects of Multi-phase and Multi-component Dynamics."
- April 24, 2008
no talk
May 2008
- May 1, 2008
nothing scheduled yet
- May 8, 2008, Robin Matoza
Scripps
"TBA"
- Monday, May 12, 2008, Chuck Wicks
USGS Menlo Park
"TBA"
- May 15, 2008, Dave Clague
Monterey Bay Aquarium Research Institute
"TBA"
- May 22, 2008, Michael Hutnak
USGS Menlo Park
"Numerical Simulations of Hydrothermal Fluid Flow and Caldera Deformation: Effects of Multi-phase and Multi-component Dynamics."
- May 29, 2008, Philipp Ruprecht
University of Washinton
"TBA"
(check back often as talk topics get finalized)
|
