|
|
Forwarded: Lost City of Ubar press release pho
Karen Carr (KAREN@CH2.CH.PDX.EDU)
Mon, 1 Aug 1994 12:25:45 PST
I thought this might be of interest to some of you; a friend of mine
at Arizona State forwarded it to me.
Subject: JPL/Lost city of Ubar, Yucatan crater images released
Sevral new images from the Spaceborne Imaging Radar-C/X-Band
Synthetic Aperture Radar (SIR-C/X-SAR) experiment that flew on
the space shuttle Endeavour in April 1994 have been released.
The images include:
P-44414: A space radar view of the site identified as that
of the lost city of Ubar on the Arabian Peninsula;
P-44423: The site of an impact crater at Chicxulub on the
Yucatan Peninsula in Mexico thought to be caused by an
asteroid or comet 65 million years ago that killed off the
dinosaurs;
P-44422: A little-known volcano in Colombia, South America.
The images are available by the following methods:
World Wide Web/Mosaic:
http://www.jpl.nasa.gov/
From the JPL home page, select "News flash" and then
the item for new SIR-C/X-SAR images. The images displayed
on the menu pages are a lower-resolution browse version.
You may also click on an item to transfer full-resolution
(up to 6.6-megabyte) versions.
Anonymous file transfer protocol (ftp):
jplinfo.jpl.nasa.gov
Browse versions are in the `news' directory as filenames
SC-*.GIF. Full-resolution versions are in the
`sircxsar/images' directory as P*.JPG (under their file
numbers).
Dialup modem:
+1 (818) 354-1333
Browse versions are in the `news' directory as filenames
SC-*.GIF. Full-resolution versions are in the
`sircxsar' directory as P*.JPG (under their file
numbers).
Hardcopy prints:
Prints may be ordered using the P- file number from the
vendor:
Newell Color Lab
221 N. Westmoreland Avenue
Los Angeles, CA 90064
USA
telephone +1 (213) 380-2980
fax +1 (213) 739-6984
Captions for the three images follow.
________________________________________________________________
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION July 28, 1994
P-44414
Ubar (L & C band)
This is a radar image of the region around the site of the
lost city of Ubar in southern Oman, on the Arabian
Peninsula. The ancient city was discovered in 1992 with
the aid of remote sensing data. Archeologists believe Ubar
existed from about 2800 B.C. to about 300 A.D. and was a
remote desert outpost where caravans were assembled for the
transport of frankincense across the desert. This image was
acquired on orbit 65 of space shuttle Endeavour on April 13,
1994 by the Spaceborne Imaging Radar C/X-Band Synthetic
Aperture Radar (SIR-C/X-SAR). The SIR-C image shown is
centered at 18.4 degrees north latitude and 53.6 degrees
east longitude. The image covers an area about 50 by 100
kilometers (31 miles by 62 miles). The image is constructed
from three of the available SIR-C channels and displays L-
band, HH (horizontal transmit and receive) data as red, C-
band HH as blue, and L-band HV (horizontal transmit,
vertical receive) as green. The prominent magenta colored
area is a region of large sand dunes, which are bright
reflectors at both L- and C-band. The prominent green areas
(L-HV) are rough limestone rocks, which form a rocky desert
floor. A major wadi, or dry stream bed, runs across the
middle of the image and is shown largely in white due to
strong radar scattering in all channels displayed (L and C
HH, L-HV). The actual site of the fortress of the lost city
of Ubar, currently under excavation, is near the Wadi close
to the center of the image. The fortress is too small to be
detected in this image. However, tracks leading to the
site, and surrounding tracks, appear as prominent, but
diffuse, reddish streaks. These tracks have been used in
modern times, but field investigations show many of these
tracks were in use in ancient times as well. Mapping of
these tracks on regional remote sensing images was a key to
recognizing the site as Ubar in 1992. This image, and
ongoing field investigations, will help shed light on a
little known early civilization.
Spaceborne Imaging Radar-C and X-Band 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), with the Deutsche Forschungsanstalt fuer
Luft und Raumfahrt e.v.(DLR), the major partner in science,
operations, and data processing of X-SAR.
#####
___________________________________________________________
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION July 28, 1994
P-44423
Chicxulub
This is a radar image of the southwest portion of the
buried Chicxulub impact crater in the Yucatan Peninsula,
Mexico. The radar image was acquired on orbit 81 of space
shuttle Endeavour on April 14, 1994 by the Spaceborne
Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-
SAR). The image is centered at 20 degrees north latitude
and 90 degrees west longitude. Scientists believe the
crater was formed by an asteroid or comet which slammed into
the Earth more than 65 million years ago. It is this
impact crater that has been linked to a major biological
catastrophe where more than 50 percent of the Earth's
species, including the dinosaurs, became extinct. The 180-
to 300-kilometer-diameter (110- to 180-mile) crater is
buried by 300 to 1,000 meters (1,000 to 3,000 feet) of
limestone. The exact size of the crater is currently being
debated by scientists. This is a total power radar image
with L-band in red, C-band in green, and the difference
between C- and L-band in blue. The 10-kilometer-wide (6-
mile) band of yellow and pink with blue patches along the
top left (northwestern side) of the image is a mangrove
swamp. The blue patches are islands of tropical forests
created by freshwater springs that emerge through fractures
in the limestone bedrock and are most abundant in the
vicinity of the buried crater rim. The fracture patterns
and wetland hydrology in this region are controlled by the
structure of the buried crater. Scientists are using the
SIR-C/X-SAR imagery to study wetland ecology and help
determine the exact size of the impact crater.
#####
____________________________________________________________
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION July 28, 1994
P-44422
Volcano/Columbia
This is a radar image of a little known volcano in northern
Colombia. The image was acquired on orbit 80 of space
shuttle Endeavour on April 14, 1994, by the Spaceborne
Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-
SAR). The volcano near the center of the image is located
at 5.6 degrees north latitude, 75.0 degrees west longitude,
about 100 kilometers (65 miles) southeast of Medellin,
Colombia. The conspicuous dark spot is a lake at the bottom
of an approximately 3-kilometer-wide (1.9-mile) volcanic
collapse depression or caldera. A cone-shaped peak on the
bottom left (northeast rim) of the caldera appears to have
been the source for a flow of material into the caldera.
This is the northern-most known volcano in South America and
because of its youthful appearance, should be considered
dormant rather than extinct. The volcano's existence
confirms a fracture zone proposed in 1985 as the northern
boundary of volcanism in the Andes. The SIR-C/X-SAR image
reveals another, older caldera further south in Colombia,
along another proposed fracture zone. Although relatively
conspicuous, these volcanoes have escaped widespread
recognition because of frequent cloud cover that hinders
remote sensing imaging in visible wavelengths. Four
separate volcanoes in the Northern Andes nations of Colombia
and Ecuador have been active during the last 10 years,
killing more than 25,000 people, including scientists who
were monitoring the volcanic activity. Detection and
monitoring of volcanoes from space provides a safe way to
investigate volcanism. The recognition of previously unknown
volcanoes is important for hazard evaluations because a
number of major eruptions this century have occurred at
mountains that were not previously recognized as volcanoes.
#####
[end]
Karen Eva Carr
History Department
Portland State University
Portland Oregon 97203
(503) 725-5472
karen@ch2.ch.pdx.edu
|