Explosive volcanic processes; Pyroclastic deposits; Volcanic hazards; Volcano monitoring
Lava domes are piles of viscous magma that, in essence, form bulbous plugs on top of volcanic vents. They grow slowly as partially solidified magma is squeezed up the volcanic conduit, and they can host high internal pressures as gases exsolving from the magma try to escape. Lava dome eruptions are notorious for they often suddenly transform from being benignly effusive to violently explosive: Sudden removal of these ‘plugs’, either by vertically-driven explosions, caused once the internal gas pressure exceeds the tensile strength of rock, or sudden collapse and spontaneous disintegration as the piles grow and become unstable, can have devastating consequences. These collapse events spawn one of the major hazard in volcanology; devastating pyroclastic density currents, which move down the flanks of the volcano at speeds of up to 60 m/s. One of the projects that I am currently working on concerns the improved understanding and forecasting of lava dome collapses and has immediate and practical applications pertaining to the management of several on-going volcanic crisis. The work is based on the Soufrière Hills volcano (SHV) eruption, Montserrat, combined with preliminary comparative studies from two other active lava dome eruptions, Mount St Helens, USA, and Santiaguito, Guatemala. Such eruptions occur with relative frequency, are potentially extremely destructive and can continue for years-to decades. The real merits will be reaped when relationships unearthed during this study are usefully and successfully applied to dome forming eruptions elsewhere.