NEW NASA COMPUTER MODELS MAY IMPROVE EARTHQUAKE FORECASTS
May
22 , 2003
John
Bluck
NASA Ames Research Center, Moffett Field, Calif.
Phone: 650/604-5026 or 604-9000
E-mail: John.G.Bluck@nasa.gov
Alan
Buis
NASA Jet Propulsion Laboratory, Pasadena, Calif.
Phone: 818/354-0474 or 354-5011
E-mail: Alan.D.Buis-116520@jpl.nasa.gov
Release: 03-40AR
Advanced
computer simulation tools 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 Jet Propulsion Laboratory, Pasadena, Calif.,
together with NASA Ames Research Center, in California's Silicon
Valley; NASA Goddard Space Flight Center, Greenbelt, Md.; 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.
"At
Ames Research Center we are using the world's largest single
system image computer to help JPL develop the software that will be
used to create QuakeSim," said Dr. Walt Brooks, chief of the NASA
Advanced Supercomputing Division at NASA Ames. "This one-of-a-kind
supercomputer is the result of a three-year joint development effort
by NASA's Office of Earth Science and the Office of Aerospace
Technology," Brooks added.
The
tools are based on 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 comprised of tens to hundreds of thousands of
measurements that show 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 to 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 on 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 it 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 also
can 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/
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