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PHOTO CAPTION
P-48145
January 7, 1997

Shown here is a portion of one of the highest-resolution images of Io
(Latitude: +10 to +60 degrees, Longitude: 180 to 225 degrees) acquired by
the Galileo spacecraft, revealing immense lava flows and other volcanic
landforms. Several high-temperature volcanic hot spots have been detected in
this region by both the Near Infrared Mapping Spectrometer and the imaging
system of Galileo. The temperatures are consistent with active silicate
volcanism in lava flows or lava lakes (which reside inside irregular
depressions called calderas). The large dark lava flow in the upper left
region of the image is more than 400 km long, similar to ancient flood
basalts on Earth and mare lavas on the Moon.

North is to the top of the picture and the sun illuminates the surface from
the left. The image covers an area 21230 kilometers wide and the smallest
features that can be discerned are 2.5 kilometers in size. This image was
taken on November 6th, 1996, at a range of 245,719 kilometers by the Solid
State Imaging (CCD) system on the Galileo Spacecraft.

Launched in October 1989, Galileo entered orbit around Jupiter on December
7, 1995. The spacecraft's mission is to conduct detailed studies of the
giant planet, its largest moons and the Jovian magnetic environment. The Jet
Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of
Space Science, Washington, DC.