Posted on 25/05/2011
Academics from Royal Holloway, University of London have been responding to the current Icelandic volcanic ash cloud.
Professor Matthew Thirlwall and Professor Agust Gudmundsson from the Department of Earth Sciences were both interviewed about the Grimsvötn volcanic eruption and the disruption to air passengers.
Professor Thirlwall has warned that although travellers may have escaped large-scale disruption to flights this time round, other eruptions in the future are inevitable. He says: "Active volcanoes can go decades, or even centuries, between eruptions and as there has only been substantial air travel for the past 40 years, we just haven't experienced the disruption. This is not an unusual phenomenon that we are seeing."
He adds: "Grimsvötn, the volcano that erupted at the weekend, also erupted in 2004 and 1998. This particular eruption was stronger than the last two and the eruption column was higher and so it travelled further across the North Atlantic leading to the disruption. Another volcano, Katla, hasn't erupted since 1918 despite previously erupting at roughly 60 year intervals, so if that does erupt we would almost certainly have widespread flight cancellations."
Unlike the eruption of Eyjafjallajökull last year, the intensity of Grimsvötn has subsided rapidly.
"The height of the eruption column indicates the productivity. Initially it was 20 kilometres but by Monday it was 5-9 kilometres, yesterday it was less than five, and today the volcano appears to be emitting only steam. The eruption column no longer has the height to continue to spread over the North Atlantic and the ash clouds that we are experiencing are those left over from the weekend. Of course, we can't definitively predict what will happen but the last two eruptions from Grimsvötn only lasted a few days so it is likely that flights should be safe in the near future."
The Geography Department’s Tephrochronological Research Group have been working for many years on the detection and analysis of volcanic ash layers in sediments which record environmental conditions over the last 15,000 years.
Since the chaos caused by last year’s ash cloud they have been working with the British Geological Survey to standardise the sample collection methods to obtain the maximum amount of information possible related to geographical extent of ash dispersal, size of ash, geochemical profiles and any potential health impacts that may arise.
Dr Simon Blockley, from the Department of Geography, said: “There are approximately 40 eruptions that we know of that have deposited ash in Britain over the last 15,000 years. Iceland is a volcanically active region. Two eruptions in two years may seem exceptional but it is often the nature of random patterns that you get clustering.”