5. Jupiter's Moon, Io

5. Jupiter's Moon, Io

Courtesy of NASA/JPL/University of Arizona

http://photojournal.jpl.nasa.gov/catalog/PIA03532


This image by Galileo spacecraft Oct. 16, 2001, shows different volcano types on Io. Center-top is a large volcanic depression, or patera, almost 100 km (60 miles) long. It may have formed after eruptions of lava emptied a magma chamber leaving empty space into which the crust collapsed. Evidence of lava flows associated with this patera, however, is scarce. Either the flows were buried, or they never erupted above the surface.
To the right is a shield volcano, similar to volcanoes in Hawaii. Lava thick enough to pile up into shields are rare on Io. Lava on Io usually runs out in long, thin flows. These lava flows could be made of sulfur.