Underground Magma Ocean Could Explain Io's 'Misplaced' Volcanoes
http://www.nasa.gov/content/goddard/io-volcano-tides
Tides flowing in a subsurface ocean of molten rock, or magma, could explain why Jupiter's moon Io appears to have its volcanoes in the "wrong" place. New NASA research implies that oceans beneath the crusts of tidally stressed moons may be more common and last longer than expected. The phenomenon applies to oceans made from either magma or water, potentially increasing the odds for life elsewhere in the universe.