This is an image of the volcano Loki.
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Volcanism of Io

Io is actively volcanic. As shown in this picture, the surface is formed almost entirely of volcanic flows or pools of volcanic material. It was during the Voyager mission to Jupiter that the active volcanism of Io was first discovered. The activity of Io was a major surprise. Io is the only body in the solar system other than the Earth known to be actively volcanic.

The volcanism of Io provides another example of a prominent kind of volcanism found on Earth, namely the formation of geysers. The two kinds of volcanism exhibited by Io are:

  • volcanoes, which form from silicate magmas similar to those of Earth
  • geysers, spouting liquid SO2.

Hotspots of Io reveal where the volcanoes are. The most well known and active volcanic features of Io are:

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