First Complete Geological Map of Jupiter's Moon Io Produced

Posted on March 19, 2012

A team of scientists - led by Arizona State University (ASU) - has produced the first complete global geologic map of Jupiter's moon. Io was discovered over 400 years ago by Galileo Galilei on January 7-13, 1610. The Io map can be downloaded here on the USGS website.

Studies of Io have shown that the orbital and gravitational relationships between Io, its sister moons Europa and Ganymede, and Jupiter cause massive, rapid flexing of its rocky crust. These tidal flexures generate tremendous heat within Io's interior, which is released through its many surface volcanoes. The highly detailed map reveals several volcanic features, including: paterae (caldera-like depressions), lava flow fields, tholi (volcanic domes), and plume deposits, as well as high mountains and large expanses of sulfur- and sulfur dioxide-rich plains.

There are no impact craters on the geologic map, because Io has no impact craters. It is the only object in the solar system without any. Io is more than 25 times more volcanically active than Earth.

David Williams, a faculty research associate in the School of Earth and Space Exploration at ASU, who led the research project, says, "Io has no impact craters; it is the only object in the Solar System where we have not seen any impact craters, testifying to Io's very active volcanic resurfacing."

Williams also says, "Because Io is so active, and continues to be studied by Earth-based telescopes, we are doing something different than producing just the paper geologic map. We are also making an online Io database, to include the geologic map, the USGS mosaics, and all useful Galileo spacecraft observations of Io. This database, when completed later this year, will allow users to track the history of surface changes due to volcanic activity. We also have proposals submitted to NASA to include in our Io database Earth-based telescopic observations and images from the February 2007 NASA New Horizons spacecraft flyby, to create a single online source to study the history of Io volcanism."

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