Press Release

New NASA Computer Models May Lead to Quake Forecast System

By SpaceRef Editor
May 22, 2003
Filed under ,

Alan Buis (818) 354-0474
Jet Propulsion Laboratory, Pasadena, Calif.

Advanced computer simulation tools now being developed by NASA and
university researchers may soon give scientists new insights into the
complex and mysterious physics of earthquakes and enable vastly
improved earthquake forecasting.

Scientists at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.,
together with NASA’s Goddard Space Flight Center, Greenbelt, Md.; Ames
Research Center, Mountain View, Calif.; and several universities, are
developing an advanced earthquake modeling system called QuakeSim.
When completed in late 2004, QuakeSim’s simulation tools will help
scientists learn more about what makes earthquakes happen.

The tools are based upon the latest technologies. For example, one
uses finite element analysis, which solves complex computer modeling
problems by breaking them into small pieces. For QuakeSim, the finite
elements are tens to hundreds of thousands of measurements of how
Earth’s crust deforms in response to movement of the giant tectonic
plates Earth’s landmasses ride upon. The measurements are gathered
through both ground and space-based techniques. The latter include
global positioning system and interferometric synthetic aperture
radar, which measure the “quiet” (non-earthquake) motions associated
with plate tectonics and the quake cycle.

QuakeSim Principal Investigator Dr. Andrea Donnellan of JPL calls
QuakeSim a vital step toward eventual earthquake forecasting. “The
deformation of Earth’s crust and the interaction between quake faults
is a complex 3-D process happening on timescales of minutes to
thousands of years,” she said. “Studying it requires sophisticated
simulation models and high-performance supercomputers. The
availability of space-based data and our current limited understanding
of quake processes make this an ideal time to develop a system for
studying deformation processes such as tectonics, quakes and
volcanoes.”

“New quake models developed under QuakeSim are expected to yield
future earthquake forecasts that will be used by a variety of federal
and state agencies to develop decision support tools that will help
mitigate losses from future large earthquakes,” Donnellan added.

QuakeSim’s three major simulation tools are Park, Virtual California
and the Geophysical Finite Element Simulation Tool (Geofest).

Park simulates the evolution of a quake on a single, unstable fault
over time. It is based upon current knowledge of the rate of movement
(or “slip”) and friction on a well-studied section of the San Andreas
Fault in Parkfield, Calif., but is applicable to any fault or
collection of faults. Park will be the tool of choice for researchers
seeking to determine the nature and detectability of quake warning
signals. It will determine how stress is distributed over a fault and
how it is redistributed by quakes or “quiet” seismic motion. It can
also be used to compute the history of slip, slip speed and stress on
a fault. Up to 1,024 computer processors will be used in parallel to
demonstrate Park’s capability.

Virtual California simulates how California’s hundreds of independent
fault segments interact and allows scientists to determine correlated
patterns of activity that can be used to forecast seismic hazard,
especially for quakes of magnitude 6 or greater. Patterns from the
simulated data are compared to patterns in real data to strengthen
understanding of the quake process. The approach’s potential is
already being demonstrated. Under a joint NASA/Department of Energy
study lead by Dr. John Rundle, director of the Center for
Computational Science and Engineering at the University of California
at Davis, Virtual California was used to identify regions of the state
with elevated probabilities of quakes over the next decade. Since the
study was completed in 2000, all of California’s five largest quakes
of magnitude 5 or greater have occurred within 11 kilometers (6.8
miles) of these sites. The probability of this occurring randomly is
about one in 100,000. The last three of these quakes occurred after
the forecast map was published in the Proceedings of the National
Academy of Sciences in February 2002.

Geofest creates 2-D and 3-D models of stress and strain in Earth’s
crust and upper mantle in a complex geologic region with many
interacting fault systems. It shows how the ground will deform in
response to a quake, how deformation changes over time following a
quake, and the net effects to the ground from a series of quakes. The
entire Southern California system of interacting faults will be
analyzed, covering a portion of the crust approximately 1,000
kilometers (621 miles) on a side. The simulation will require
millions of equations and hundreds of computer processors.

In addition to JPL, the QuakeSim team includes the Davis and
Irvine campuses of the University of California; Brown University,
Providence, R.I.; Indiana University; and the University of Southern
California. An independent review board provides oversight. Codes
will be run on supercomputers at NASA’s Goddard, Ames and JPL
facilities and other institutions. The California Institute of
Technology in Pasadena manages JPL for NASA.

NASA’s Earth Science Enterprise is dedicated to understanding Earth as
an integrated system and applying Earth system science to improve
prediction of climate, weather and natural hazards using the unique
vantage point of space. A primary goal of NASA’s solid Earth science
program is assessment and mitigation of natural hazards. QuakeSim
supports the Enterprise’s goal of developing predictive capabilities
for quake hazards.

To learn more, see: http://quakesim.jpl.nasa.gov and
http://pat.jpl.nasa.gov/public/RIVA/.

SpaceRef staff editor.