Press Release

Volcano Research Erupts In Space

By SpaceRef Editor
July 16, 2001
Filed under ,

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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Note to Broadcasters: A video file to accompany this release will air on NASA
Television on Wednesday, July 18; Thursday, July 19; and Friday, July 20. A live-shot
television interview opportunity with NASA volcanologist Michael Abrams is available
via NASA Television on Thursday, July 19, from 3-7 p.m. ET). To book an interview,
call Jack Dawson, (818) 354-0040. For NASA Television schedule information see
http://www.nasa.gov/ntv/breaking.html .

SpaceRef staff editor.