PHOENIX, March 20 (UPI) -- A geologic map of Jupiter's moon Io shows some of the most geologically unique and active volcanoes ever documented in the solar system, U.S. researchers say.
The map, published by the U.S. Geological Survey with input from Arizona State University scientists, is the first such depiction of the innermost of Jupiter's largest moon.
The orbital and gravitational relationships between Io, its sister moons Europa and Ganymede, and Jupiter cause massive, rapid flexing of its rocky crust that generates tremendous heat within Io's interior, which is released through the many surface volcanoes observed.
"One of the reasons for making this map was to create a tool for continuing scientific studies of Io, and a tool for target planning of Io observations on future missions to the Jupiter system," ASU researcher David Williams said in a university release Tuesday.
Io is extremely active, with hundreds of volcanic sources on its surface.
"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 said.