Annual Meeting - SCEC.org

Workshops
SCEC Research Accomplishments | Report
SCEC supported three workshops related to crustal deformation modeling in 2010, covering (i) finite-element deformation
modeling, (ii) integrating GPS into the UCERF3 process, and (iii) comparing earthquake simulators.
The ninth annual Workshop on Crustal Deformation Modeling (June 14-18, 2010, in Golden Colorado) was co-sponsored by
SCEC and the Computational Infrastructure for Geodynamics (CIG), and attracted 68 participants. The first two days were
dedicated to training in the use of state-of-the-art finite-element codes for modeling crustal deformation with the remaining
three days filled with science talks and discussions. See http://www.geodynamics.org/cig/workinggroups/short/workshops/cdm-
10/agenda for the complete agenda and slides for all of the presentations. This year’s workshop included several presentations
on the recent Haiti, Chile, and El Mayor-Cucapah earthquakes along with talks on fault and bulk rheologies with a focus on
the base of the seismogenic zone. A discussion at the end of the workshop indicated overwhelming support for continuing the
series of annual workshops. In early 2011 the organizing committee decided that in order to keep the scientific agenda fresh
and increase interest among leading researchers, we will switch to biannual meetings and skip holding a workshop in 2011.
Instead we will hold a virtual (online) workshop in 2011 focused solely on training users in the use of PyLith and related codes
for modeling crustal deformation. This experiment with online training should enable us to determine if this approach is
effective and how to distribute our efforts in the future between in-person training at workshops versus online training.
Figure 38. Slip rate estimates on some fault
segments from elastic block models, supplied by
GPS-UCERF workshop participants. Right-lateral
is positive. Left-lateral is negative. Results shown
here were provided by Rob McCaffrey; Brendan
Meade and Jack Loveless; and Kaj Johnson and
Raymond Chuang. From Kaj Johnson. (This
exercise has been superceded by a new block
modeling test exercise, developed in 2011 by Kaj
Johnson.)
In April 2010, the inaugural workshop on incorporating geodetic
surface deformation data into UCERF3 was held in Pomona, California
(42 attendees, by invitation). A number of goals potentially achievable
within a year were identified including (1) slip rate estimates—with
uncertainties or ranges—for all major and some minor faults of the
extended San Andreas system; (2) strain rate estimates or bounds on
rates for selected regions lying off the major faults of the San Andreas
system; and (3) corrections or bounds on perturbing effects of postseismic
deformation and elastic crustal moduli heterogeneities on the
observed GPS velocity field. Test exercises related to these items
included a comparison of southern California strain rate fields
generated by several researchers (coordinated by David Sandwell,
Scripps), a block modeling test exercise, using the SCEC GPS velocity
field (version 3) and a specified block model geometry (coordinated by
Kaj Johnson, Indiana U), and an exercise exploring the range of fault
slip rates, locking depths, interseismic moment accumulation that
might be inferred from a GPS velocity profile across a single fault
(coordinated by Elizabeth Hearn, UBC). The results of the former two
activities (Figures 37 and Figure 38) indicated large discrepancies,
which need to be understood before we provide information to
WGCEP.
Immediate follow-on activities were identified to begin implementing
the goals enumerated here. These include tightly focused mini- and
micro- workshops of 5 to 20 participants each that would be oriented
along the same niche specialist lines as the 3 main Pomona workshop
sessions. The first of these workshops was held in Golden, Colorado in
July (a micro-workshop with just the four organizers of the main
workshop, Ned Field (USGS/WGCEP), and a few other participants)
and a mini-workshop with some 20 attendees at the SCEC Annual Meeting in September 2010. In 2011, micro-workshops will
focus on a revised block model comparison exercise, and a range of GPS-inferred slip rates will be delivered to WGCEP well
in advance of the final due date for UCERF3. A detailed summary of the April 2010 GPS-UCERF3 workshop is here:
(http://sceccore.usc.edu/proposalfiles/2010reports/Thatcher_10082_report.pdf). A shorter version of this appeared in Transactions of
the AGU (Hearn et al., 2010).
In July 2010, Terry Tullis lead a workshop for 25 attendees (by invitation). The principal purposes of the workshop were to
allow the participants 1) to compare the results from the first simulations to use our common input and output formats and
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