Four views of the volcano Loki Patera on Jupiter's moon Io showing changes
seen on June 27th, 1996 by the Galileo spacecraft as compared to views seen
by the Voyager spacecraft during the 1979 flybys. Clockwise from upper left
is a Voyager 1 high resolution image, a Voyager 1 color image, a Galileo
color image, and a Voyager 2 color image. North is to the top of the
picture. During the Voyager flybys large dense volcanic plumes erupting from
each end of the dark linear 'fissure' to the northeast of the dark caldera
and plume deposits obscured much of the surrounding surface. These dark jets
are not visible in the Galileo image, and other images have confirmed that
the Loki plumes were inactive during this Galileo encounter. Ground-based
observers have determined that the Loki hot spot, historically the most
energetic on Io, has been unusually dim. The fissure appears extended and
elongated to the east and southwest, perhaps also resulting in a migration
of the plume vents. There is an enlarged dark spot to the west of Loki. The
materials just south and northeast of the caldera appear more reddish color.
Images are 894 km wide.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's
Office of Space Science, Washington, DC.