Research Fellows Directory
Dr Michael James
My research is aimed at improving our understanding of how lavas from volcanoes flow, cool and eventually come to a stop. Being able to reliably and accurately forecast the length of lava flows is important for many civil authorities at volcanoes around the world, but is not yet possible.
Molten lava is made of a liquid melt in which there are also various amounts of gas bubbles and solid crystals. Thus, lavas are complex mixtures of gas, liquid and solid phases and, consequently, exhibit a wide variety of flow behaviours. Once erupted, the surface of hot lava cools quickly by radiating heat into the atmosphere and this cooling eventually results in the flow becoming sufficiently rigid that it can no longer advance, and it stops. During flow, many lavas form levee-bounded channel which deliver fresh lava from the vent relatively efficiently to the flow front. However, in some cases, as the lava surface chills, it can become sufficiently strong that it stops moving, whilst hotter lava underneath continues to flow. The result of this process is the formation of a lava tube, and lava flowing in a tube can advance over much longer distances because it cools slowly, being effectively insulated from radiating heat to the atmosphere.
Although we can simulate the advance of individual lava flows reasonably well, the formation of lava tubes cannot yet be automatically determined by computer models. In order to improve such models, measurements of lava flows in the process of stopping or forming tubes need to be obtained. I am using digital and thermal cameras, along with computer vision and photogrammetry techniques to capture these processes. The results provide insight into the flow dynamics that can then be used to improve our models of lava flows and, ultimately, to validate models of tube formation. I work with researchers at INGV Catania, whose flow models are regularly used to assess the volcanic hazards and associated risk at Mount Etna, Sicily.