I work principally on explosive volcanism and its products. I am interested in the deep ascent of magma through the crust, the assembly of shallow magma chambers, the triggering of eruptions, and the timescales on which these processes take place. This work exploits petrological techniques including melt inclusion volatile content and intracrystalline diffusion chronometry. I have also worked on the dynamics of pyroclastic flow emplacement and on the formation of calderas, via a combination of field and experimental techniques. My main field areas have included Santorini caldera (Greece), Soufrière Hills Volcano (Montserrat, Antilles) and Crater Lake (Oregon).