Io's rock or silicate shell extends to the surface. This is the highest resolution color global mosaic of Io. It was then projected to an ortographic projection centered at 0 degrees latitude and 315 degrees longitude. Almost all the features visible here have volcanic origins, including several calderas and eruption plumes that were active at the time of the Voyager 1 encounter. Global Mercator Mosaic Io's volcanic plains are shown in this Voyager 1 image mosaic which covers the area roughly from latitude 60 degrees N. to latitude 60 degrees S. and longitude 100-345.
North is up.
Numerous volcanic calderas, lava flows, and volcanic eruption plumes are visible here. The bright whitish patches probably consist of freshly deposited sulfur dioxide frost. This image of Jupiter and its satellite Io were taken on March 5, 1994. Io is too small for ground-based telescopes to see the surface details. Several of the volcanoes periodically are active because Io is heated by tides raised by Jupiter's powerful gravity.