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sc-pinat.txt
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1995-02-23
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PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION P-43915
April 15, 1994
Mount Pinatubo L&C band
This is a false color L-band and C-band image of the area around
Mount Pinatubo in the Philippines, centered at about 15 degrees
north latitude, 120.5 degrees east longitude. This image was
acquired by the Spaceborne Imaging Radar-C and X-Band Synthetic
Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour
on orbit 78 on April 13, 1994. The false-color composite is made
by displaying the L-band HH return in red, the L-band HV return
in green and the C-band HV return in blue. The area shown is
approximately 45 by 68 kilometers (28 by 42 miles). The main
volcanic crater on Mount Pinatubo produced by the June 1991
eruptions, and the steep slopes on the upper flanks of the
volcano, are easily seen in this image. The red color on the
high slopes show the rougher ash deposited during the 1991
eruption. The dark drainages are the smooth mudflows which
continue to flood the river valleys after heavy rain. Radar
images such as this one can be used to identify the areas flooded
by mudflows, which are difficult to distinguish visually, and to
assess the rate at which the erosion and deposition continues. A
key aspect of the second SIR-C/X-SAR mission in August 1994 will
be to collect a second image of Pinatubo during the summer
monsoon season -- new mudflows will have occurred -- and to
evaluate the short-term changes. The 1991 eruption of Mount
Pinatubo in the Philippines is well known for its near-global
effects on the atmosphere and climate due to the large amount of
sulfur dioxide that was injected into the upper atmosphere. What
is less widely known is that even today the volcano continues to
be a major hazard to the people who have returned to the area
around the volcano. Dangerous mudflows (called "lahars") are
often generated by heavy rains, and these can still sweep down
river valleys and wash out roads and villages, or bury low lying
areas in several meters of mud and volcanic debris. These
mudflows will continue to be a severe hazard around Pinatubo for
the next 10 to 15 years.
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Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar
(SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The
radars illuminate Earth with microwaves allowing detailed
observations at any time, regardless of weather or sunlight
conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band
(24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency
data will be used by the international scientific community to
better understand the global environment and how it is changing.
The SIR-C/X-SAR data, complemented by aircraft and ground
studies, will give scientists clearer insights into those
environmental changes which are caused by nature and those
changes which are induced by human activity. SIR-C was developed
by NASA's Jet Propulsion Laboratory. X-SAR was developed by the
Dornier and Alenia Spazio companies for the German space agency,
Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the
Italian space agency, Agenzia Spaziale Italiana (ASI).
#####