[unav_all] AGU Special Session T33

clangstn clangstn at memphis.edu
Fri Aug 17 08:57:19 MDT 2007

Dear Colleagues,
Please consider submitting an abstract to our provocative session T33 "
Intraplate Earthquakes Know No Boundaries" to be held at the American
Geophysical Union (AGU) Fall Meeting on 10-14 December 2007 in San
Francisco, California.
Abstract Deadline is September 6, 2007.
Further information and abstract submission procedures are available at:
The problem of intraplate earthquakes is a geological puzzle that has no
clear physical mechanism or scientific paradigm.  Recent controversies on
the activity or non-activity of present source zones from GPS measurements,
the possible migration of seismicity in continental interiors, and efforts
to understand the physical state of the crust within continents away from
plate boundaries through EarthScope and other large scale experiments makes
a review of the tectonic mechanisms for intraplate events timely.
In this session, we hope to discuss competing models of driving mechanisms
for intraplate earthquakes and stimulate new thinking on this long-standing
problem. Multiple orogenic and thermal events in Earth's history have
produced a fertile environment for earthquake nucleation within the
continents. Simple plate kinematics combined with first-order differences
between continental and oceanic lithospheric rheologies suggest that
continental edges and plate boundaries are the most likely places for
earthquake generation in the crust. However, intraplate earthquakes are far
from the well-springs of warm, pliable plate boundaries that strain
continuously to take up plate motion. If plates behave rigidly, the standard
elastic/plastic rheological model predicts that no stress is stored in the
viscoelastic reservoirs of intraplate lithosphere so that the elastic
portions of the upper crust, lower crust and upper mantle must support
local, regional, and plate-wide stress fields. What are these stress fields
and what causes time-dependent changes in the strength of the intraplate
lithosphere?  Do time-dependent changes in the state of driving stresses
produce intraplate seismicity?  Is there geological, geophysical,
hydrogeophysical, or geochemical evidence for spatial or temporal migration
of seismicity in continental interiors? Papers aimed at exploring mechanisms
for intraplate seismicity and mid-continent tectonism for North America are
encouraged, although presentations related to global intraplate events and
processes are also welcome.
Convened by Charles Langston (clangstn at memphis.edu, University of Memphis)
and Lorraine Wolf (wolflor at auburn.edu, Auburn University)

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