This is an image of the surface of Io, looking down on a volcano and the lava plain surrounding it.
Click on image for full size
NASA

Surface of Io

Unlike the other moons of Jupiter, Io is not made of ice. In fact, the surface of Io is rocky with many volcanoes. The volcanoes pour out lava of sulfur from the inside of Io.

The surface of Io can be cold enough for frost, however. White patches in the image indicate areas of frost on the surface.

The biggest volcanos of Io are called Loki and Prometheus. Between the volcanos are lava plains, much like those found in Hawaii near a volcano.

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