At the time of the Voyager mission Io was known to have at least 8 volcanos. To date, that number has increased to 11. This one, photo- graphed erupting, is blasting gas and dust 160 kilometers above its surface. Because of the continuous eruptions and lakes of lava, the surface of Io changes constantly. Volcanos on Io, unlike those observed on Venus and Mars, are not cone-shaped but look as though they have collapsed in on them- selves.
