Jenny Woods works in the Cambridge volcano seismology group investigating micro earthquakes produced by movement of magma in volcanic systems, studying in detail the 2014 intrusion and fissure eruption from the Bardarbunga volcano in Iceland. Lying on a divergent plate boundary, Iceland experiences a great deal of volcanism, as ‘rift zones’ accommodate the spreading through faulting and injection of molten rock through the crust. These crustal intrusions are incredibly common (on a geological timescale!) but the dynamics of their propagation are not fully understood. The earthquakes that arise from rock fracture and failure as the magma forces its way through the crust reveal the physical source processes at play during these melt intrusion events.