My current research is about how highly viscous silica-rich magma rises within volcanoes. As shown in the last fifteen years by Donald Dingwell and colleagues, magma may either fracture brittly or flow in a ductile manner, depending upon the viscosity of the magma and how rapidly it is deformed. Whether magma fractures or flows will largely determine whether an eruption will be explosive and what kind of warning signals could be detected prior to its onset, because fracturing may release volcanic gases and generate small earthquakes. As recent fieldwork in Iceland has shown, some silicic magma may go through multiple cycles of fracture and flow, generating intricately flow banded obsidian (see picture).

I will combine detailed study of the geological record of fracture and flow preserved in Icelandic obsidian with laboratory experiments on obsidian samples at University College London in collaboration with Peter Sammonds, that aim to simulate the conditions required for contrasting styles of magma deformation. The triggering of volcanic earthquakes, patterns of gas loss from magma and thresholds of brittle-ductile behaviour are topics of particular interest.

I'm collaborating with Jonathan Castro (Smithsonian Institution) to study patterns of vesiculation, degassing and spherulite growth in obsidian at Krafla.