A spectacular landslide within the low-brightness region of Iapetus's surface
known as Cassini Regio is visible in this image from Cassini. Iapetus is one
of the moons of Saturn.
The landslide material appears to have collapsed from a scarp 15 kilometers
high (9 miles) that forms the rim of an ancient 600 kilometer (375 mile) impact
basin. Unconsolidated rubble from the landslide extends halfway across a
conspicuous, 120-kilometer diameter (75-mile) flat-floored impact crater that
lies just inside the basin scarp.
Landslides are common geological phenomena on many planetary bodies,
including Earth and Mars. The appearance of this landslide on an icy satellite
with low-brightness cratered terrain is reminiscent of landslide features that
were observed during NASA's Galileo mission on the Jovian satellite Callisto.
The fact that the Iapetus landslide traveled many kilometers from the basin
scarp could indicate that the surface material is very fine-grained, and
perhaps was fluffed by mechanical forces that allowed the landslide debris
to flow extended distances.
In this view, north is to the left of the picture and solar illumination is from
the bottom of the frame. The image was obtained in visible light with the
Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance
of about 123,400 kilometers (76,677 miles) from Iapetus and at a
Sun-Iapetus-spacecraft, or phase, angle of 78 degrees. Resolution
achieved in the original image was 740 meters (2,428 feet) per pixel.
The image has been contrast-enhanced and magnified by a factor of
two to aid visibility.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet Propulsion
Laboratory, a division of the California Institute of Technology in
Pasadena, manages the mission for NASA's Science Mission Directorate,
Washington, D.C. The Cassini orbiter and its two onboard cameras were
designed, developed and assembled at JPL. The imaging team is based at
the Space Science Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov. For images visit the Cassini
imaging team home page http://ciclops.org.