Fire, ice, and Eyjafjallajökull 23 September 2010Posted by admin in current research, Eyjafjöll, geoscience, Iceland, natural hazards, volcanology.
A fascinating article in Science News, magazine of the Society for Science and the Public, explores the role of ice in volcanism with particular reference to the eruption of Iceland’s Eyjafjallajökull earlier this year. When Eyjafjallajökull erupted on 20 March 2010 it began with a fissure eruption characterized by relatively quiet effusive activity and limited ash emissions. This changed in mid-April when the seat of the eruption moved west to an area beneath the ice-cap. As the eruption became sub-glacial, explosivity and ash production increased, with the disruptive consequences that we are all familiar with.
The Science News article, an excellent piece of work by Alexandra Witze, looks at some of the research that is now going on in the wake of the Eyjafjallajökull eruption to explore the crucial issue of glaciovolcanism – the interaction between volcanic activity and ice.
Eyjafjallajökull’s eruption has refocused attention on a small but rapidly growing subset of volcanology: the study of volcano-ice interactions. Ice-covered volcanoes, or “glaciovolcanoes,” are not fundamentally different from other volcanoes in terms of plumbing or eruptive style. But they distinguish themselves the moment magma breaks through the crust and meets ice.
One reason to study icy volcanoes is to better understand their risks. Nobody died in the Eyjafjallajökull eruption, but in 1985 an eruption beneath an icy mountain in the Colombian Andes sent massive mudflows coursing downstream, killing more than 20,000 people. Dozens of volcanoes mantled with ice are scattered around the world, each posing a distinct hazard.
The volcano responsible for that killer eruption of 1985 was of course Nevado del Ruiz; the 25th anniversary of that event will be on 13 November this year. At Nevado del Ruiz human failings in monitoring and communication (along with unfortunate weather conditions that obscured the summit) rather than geology were to blame for the scale of the disaster, but the eruption certainly illustrates the particularly hazardous nature of ice-capped volcanoes.
Fire & ice: volcanoes and frozen lands make an explosive combo – Science News, 25 September 2010