Repeat of Icelandic ash cloud ‘unlikely’

A new report published in the Journal of Geology claims that a volcanic ash cloud similar to the 2010 Eyjafjallajokull eruption is unlikely to cause chaos in Europe again ‘in our lifetimes’ — if the last 7,000 years of history are a good guide.

Following the economic damage caused across Northern Europe in 2010, researchers decided to analyse records of such clouds across the region. Their results showed that large ash clouds like in 2010 affected the region only every 56 years, on average.

7,000 years’ worth of volcanic ash records are stored naturally in peat bogs and lake beds. Combined with historic written accounts of volcanic ash clouds, the sediment records were analysed from sites in the UK, Ireland, Germany, Scandinavia and the Faroe Islands to try to figure out how often Eyjafjallajokull-style ash clouds occur.

The best-preserved records cover the last 1,000 years and in that period ash has fallen on Northern Europe every 56 years, on average. There is a roughly 16 percent chance of ash fall every decade.

Over the whole 7,000-year-period, scientists found 38 tephra layers in Scandinavia, 33 in Ireland, 14 in the UK and 11 in Germany — the frequency apparently decreasing with increased distance from Iceland and due to prevailing wind patterns.

Chemical analysis showed that about a third comes from just one volcano: Hekla.

A BBC report says that there are many more eruptions in Iceland than there are far-reaching ash clouds — averaging 20-25 eruptions every hundred years over the last 1,000 years.

The researchers’ results indicate that ash clouds had little impact on Europeans before the age of aviation. “We can look at particular eruptions and try to find out if there were changes in climate or changes in agricultural practices at the time, but I haven’t found any correlation. I think we’re pretty resilient,” report co-author Gill Plunkett of Queen’s University in Belfast told the BBC.

Statistics like the above are useful over large time spans; but the nature of volcanoes is such that they can erupt at any time with little warning and total disregard for statistics. Most Icelandic eruptions, however, have few negative impacts on people’s daily lives and usually do not cause widespread delays to airlines and their customers.

(Photos: Anders Peter Amsnæs)

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