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JET PROPULSION LABORATORY
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http://www.jpl.nasa.gov

Contact:  Rosemary Sullivant, (818) 354-0474

FOR IMMEDIATE RELEASE  				July 16, 2001

VOLCANO RESEARCH ERUPTS IN SPACE

     The view from the rim of Mt. St. Helens may be thrilling, but one of
the best and safest ways to study volcanoes is from space. New spaceborne
instruments let scientists peer deep into volcanoes and learn about their
behavior.

     "We now have a view toward the center of Earth," says volcanologist
Michael Abrams of NASA's Jet Propulsion Laboratory, Pasadena, Calif.
"Previously, we had to depend on on-site observations not easily 
accomplished when a volcano was actively erupting. Now we can safely view
them from space and obtain fast, accurate information from satellites."

     Erupting volcanoes cause casualties, destroy property and devastate
local areas. They can also affect regional air quality and visibility
with implications ranging from  public health to air traffic control. For
example, a large eruption by the Popocatepetl volcano near Mexico City
has serious consequences for the more than one million people living
within 30 kilometers (19 miles) of the volcano. 

     Now, instruments such as radiometers, spectrometers and
interferometers fly far above Earth's surface year-round. They provide
scientists with continual coverage of the approximately 500 active
volcanoes around the world. The new information they provide makes it
possible to do long-term monitoring, develop new research techniques and 
create detailed images and videos, according to JPL researchers.

     Data collected over time can be turned into computer animation that
provides dynamic evidence of changes to scientists, government officials
and the interested public.  "We are pioneering the use of powerful
commercial animation software to visualize dynamic volcanic processes
such as lava flows, ground deformation, and the appearance and growth of
hot spots," says Dr. Vince Realmuto of JPL's Digital Image Animation 
Laboratory.

     The Advanced Spaceborne Thermal Emission and Reflection Radiometer is
an  imaging instrument flying on Terra, a satellite launched in December
1999 as part of NASA's Earth Observing System.  It is being used to obtain
detailed maps of land surface temperature, radiation emissions,
reflectance and elevation. The instrument helps scientists monitor
volcanoes worldwide as they look for unusual thermal features and 
changes in the output of sulfur dioxide, a major air pollutant that is
vented by some volcanoes.  Particular attention is currently being
directed to Popocatepetl, as well as  Kilauea in Hawaii and Mount Etna in
Sicily.  

     Also flying on Terra is the Multi-angle Imaging SpectroRadiometer.
Viewing the  sunlit Earth simultaneously at nine widely spaced angles,
this instrument produces detailed images of Earth in four colors at every
angle. These images are carefully  calibrated to provide accurate measures
of the brightness, contrast and color of reflected  sunlight. The
instrument can identify even very thin clouds of airborne particles
emitted  by volcanoes and can sense the cloud height, particle amount and
type.

     "The multi-angle imaging techniques pioneered by this instrument
allow us to detect very small amounts of airborne particles, including
volcanic plumes, from space. We can also distinguish non-spherical
particles such as mineral dust from pollution and  maritime particles,
which helps us identify aerosols of volcanic origin," says JPL's 
aerosol scientist Dr. Ralph Kahn.

     The Shuttle Radar Topography Mission, launched on Space Shuttle
Endeavour in February 2000, uses a technique called radar interferometry.
Differences between two radar images taken from slightly different
locations allow for the calculation of surface  elevation. According to
Dr. Tom Farr, a JPL geologist, "The three-dimensional shapes of volcanoes
we get with this data gives volcanologists information on the types of 
eruptions, ash flow and erosion patterns."

     Synthetic aperture radar interferometry data from the European Remote
Sensing  satellite enables researchers to see how the volcano "breathes,"
or the changes within and beneath the volcano that cause the surface to
expand or contract.  "InSAR is one of the keys to revolutionizing our
ability to view volcano deformation with complete spatial  coverage of
almost the entire globe," says Dr. Paul Lundgren, a JPL geophysicist.
	
     The Terra and SRTM missions are included in NASA's Earth Science
Enterprise, whose goal is to obtain a better understanding of the
interactions between the biosphere,  hydrosphere, lithosphere and
atmosphere.  JPL is managed for NASA by the California  Institute of
Technology in Pasadena.
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7/16/01  RS
2001-147