Previously, scientists had thought that Icelandic magma was less "fizzy" -- containing less volcanic gases like carbon dioxide -- than that in Pacific Ocean volcanoes, and expected much less explosive eruptions by comparison.
However, research by Britain's The Open University and Lancaster University said they've found evidence of Icelandic magma twice as "fizzy" as previously believed, increasing the likelihood of future eruptions like that of the Eyjafjallajokull volcano in 2010 that created ash clouds that disrupted air travel over large parts of Europe.
The researchers analyzed pumice and lava from an eruption at Iceland's Torfajokull volcano some 70,000 years ago to search for evidence of the levels of gases from water and carbon dioxide in the eruption.
"I was amazed by what I found," Lancaster University doctoral student Jacqui Owen said. "I measured up to 5 percent of water in the inclusions, more than double what was expected for Iceland, and similar in fact to the values for explosive eruptions in the Pacific 'Ring of Fire'.
"We knew the Torfajokull volcanic eruption was huge -- almost 100 times bigger than recent eruptions in Iceland -- but now we also know it was surprisingly gas-rich."
The researchers said their study shows Icelandic volcanoes have the power to generate the fine ash capable of being transported long distances and cause disruption across Europe.
With worrying evidence of increased volcanic activity, "Iceland's position close to mainland Europe and the north Atlantic flight corridors means air travel could be affected again," Lancaster researcher Hugh Tuffen said.