on Io. This observation indicates that these two structures are somehow related. As Io has strong tidal heating and very violent volcanic activities, the interior of Io should be vigorously convecting). Localized regions of up-welling and down-welling of mantle material could affect the stress field in Io's lithosphere. Buoyant mantle diapir can locally enhance the compressive stress which may be sufficient for the development of thrust faults. This mechanism would predict curved and circular mountains if it were responsible for the initiating faulting. However, many Ionian mountains are observed to have straight margins. This contradiction indicates that faults exist before the raising of diapirs. Thus, diapirs only provide a mechanism for focusing the stresses in Io's lithosphere. Fractures that are not under compression stress induced by underlying diapiring processes could serve as conduits through which the melt erupts onto the surface. Meanwhile, in a global view, an anti-correlation between the distributions of mountains and volcanic centers is observed on Io. This may reflect a global convective pattern. On the hemisphere which is dominated by up-welling, there are more volcanic centers. On the hemisphere that is dominated by down-welling, there are more mountains. See also Volcanology of Io List of mountains on Io References External links Io image archive from the Galileo mission Io images Topography and Mountains on Io Io in 3-D Tidal Heating tutorial