Compared to Earth, more "oomph" is required to bring magma to the surface of Mars, and this is probably why we haven't seen any recent eruptions on the red planet.
What is Mars made of? We hear from a scientist who will be part of the team analysing 'marsquake' seismic data and orbital imagery from the InSight mission to the red planet.
The InSight Lander mission to Mars is preparing for launch in May 2018. But there are seven (or eight) other planets to explore: why have we such a hang up on Mars?