The Prometheus plume is seen rising about 75 kilometres Jupiterś volcanic moon Io. (via APOD: 2011 May 22 - Io: The Prometheus Plume)
You can see two eruptions in this pic of Jupiter’s moon, Io. At the top, a plume rises from Pillan Patera, a volcanic caldera. In the middle, near the shadow line, you can see the plum from Prometheus, which has been visible since the Voyager flybys in 1979. Check out this close-up.