An internal heat source under a frozen crust can result in volcanism.

© Charles Chandler

 

This might also explain geysers on Mars and on Enceladus, and eruptions on Io.

 

Note that once an eruption forms, the hotter magma is a better conductor. Thus it acts like a lightning rod for all charge exchanges in the layers that it crosses. The result can be a continuous flow of magma that is being "pumped" by ohmic heating.