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Contact: Mary A. Hardin
FOR IMMEDIATE RELEASEOCTOBER 20, 1997
SCIENTISTS DISCOVER POSSIBLE IMPACT CRATER IN YEMEN
Scientists using a variety of spaceborne remote-sensing
images, combined with limited ground research, have discovered
what they think is a possible impact crater in a dry river bed in
the Yemen Arab Republic.
"On the remote-sensing images, the proposed crater appears
as a 770-meter-diameter (2,525-foot) circular feature centered on
a small wadi or dry river channel. Although sharp on the remote-
sensing images, the feature is unremarkable in the field," said
Dr. Ronald Blom, a research geologist at NASA's Jet Propulsion
Laboratory. "This is another example of how remote-sensing tools
help us see things we wouldn't normally be able to detect, or
might overlook, on the ground."
Blom and his colleague Dr. Robert Crippen, also of JPL, are
presenting their findings this week at the annual meeting of the
Geological Society of America, being held in Salt Lake City. The
image is available at http://www.jpl.nasa.gov/news .
They used radar images from the Spaceborne Imaging Radar
C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice
on the space shuttle in 1994, and enhanced visible and near-
infrared images from the Landsat Thematic Mapper satellite.
"A very brief field reconnaissance in January 1997
indicates, but does not confirm, that the feature may well be an
impact crater," Blom explained. "The crater is in a wadi that is
filled with sediment and windblown sand. No direct evidence of
an impact, such as overturned rims, shatter cones, or meteoritic
material, were observed. However, large circular features are
uncommon. Other potential explanations for this circular feature
include a sinkhole or volcanic crater. But there was no field
evidence of volcanic or sinkhole activity. Thus, neither seems
likely in this case."
SIR-C/X-SAR, a joint mission with NASA and the German and
Italian space agencies, is managed by JPL, a division of the
California Institute of Technology, for NASA's Office of Mission
to Planet Earth, Washington, DC. Blom's field work was sponsored
by New Wave International and the Kaplan Fund.