After formation is complete, the surfaces of planets continue to be modified by surface processes including tectonics and volcanism.
Discovery of active volcanism on the satellite Io was probably the greatest surprise.
It outlines how results from research at Soufriere Hills, Montserrat and Mount St Helens are beginning to transform the understanding of explosive volcanism.
A reanalysis of the Mariner data provides some preliminary evidence of recent volcanism on Mercury.
A common explanation for the hot-spots that cause intra-plate volcanism is the existence of steady plumes rising from the core-mantle boundary.