Askja (photo courtesy of John Cassidy)
Dr Hazel Rymer, a volcanologist at The Open University, presented scientific evidence today suggesting that Askja, an active volcano in North Iceland, is showing signs of a build up to an eruption.
Dr Rymer has measured gravity at Iceland’s Askja volcano since 1985, with help from volunteers at environmental charity Earthwatch. Until 2007, the patterns were consistent; deflation of the ground (relaxation) and gravity decreases, which she interprets in terms of drainage of magma out of the Askja system. In 2008 this changed. The deflation reduced slightly and gravity began to increase, which she interprets as being due to new magma intruding beneath the volcano. This trend was confirmed in 2009.
The results are consistent with seismicity which has been seen in the area since 2008. New magma accumulating beneath a volcano is what happens before an eruption. A critical amount needs to accumulate and we cannot say what that is. I can say that the rate of intrusion far exceeds the previous rate of drainage. For the last few hundred years, Askja has erupted every 40 years or so. It last erupted in 1961.
Dr Rymer says: “The last time Askja had a large, explosive eruption was in 1875. The hole that was left behind was 5km across and 200m deep. It didn’t erupt ash for very long but while it did it threw it over a large amount of Iceland and some of the ash did make it over as far as Scandinavia and Scotland. It quite possibly affected other places as well, it’s just not been identified as back in 1875 records wouldn’t have been as good as they are now and of course people weren’t trying to fly through it.
“Of course another volcanic ash cloud affecting flights is possible. But I think we’re getting better and better at predicting which way the wind is blowing and measuring the density of cloud, so I think the consequences will be a lot better than grounding the whole of European airspace again.”
This research was funded by the Natural Environment Research Council (NERC) and Earthwatch.
Biography: Dr Hazel Rymer
Dr Hazel Rymer is presently Senior Lecturer in Environmental Geophysics based in the Department of Earth & Environmental Sciences at The Open University.
Dr Rymer developed and championed the use of microgravity as a tool for monitoring active volcanoes. She has used this method to identify sub-surface processes at calderas in a state of unrest and at persistently active volcanoes and this has given geoscientists considerable insight into the range of mechanisms responsible for initiating and sustaining volcanic activity.
The technique Dr Rymer pioneered is now the standard method for gravity monitoring on volcanoes; it remains the only way to quantify the sub-surface mass changes that occur before, during and after eruptions.
About research at The Open University
The Open University supports a vibrant research portfolio and in the UK's latest Research Assessment Exercise (RAE 2008), it climbed 23 places to 43rd, securing a place in the UK's top 50 higher education institutions. Results showed that more than 50% of the OU’s research is internationally excellent (3*), with a significant proportion world-leading (4*).
Open Research Online (ORO), the OU’s freely accessible repository of research publications, is available at: http://oro.open.ac.uk. ORO has around 30,000 visitors from 170 different countries each month, and is currently ranked the fifth in the UK by the Registry of Open Access Repositories (ROAR).
Earthwatch is an international environmental charity whose mission is to engage people worldwide in scientific field research and education to promote the understanding and action necessary for a sustainable environment.
Earthwatch currently supports 50 environmental research projects in 24 countries by providing funds and paying volunteers who work alongside leading field scientists and researchers.
To ensure our research addresses pressing global environmental issues, Earthwatch preferentially funds projects that fit the focus of one or more of the following priority research areas: ecosystem services, climate change, oceans and cultural heritage.
More than 91,000 volunteers have joined Earthwatch scientists in the field since the charity began in 1971, contributing thousands of days to essential fieldwork.
Earthwatch website: http://www.earthwatch.org/europe