A small volcanic eruption in Iceland's Bardarbunga system has now stopped, and all airspace restrictions have been lifted.
But experts have warned the worst may not be over, with a major eruption causing an ash cloud similar to the 2010 eruption at the Eyjafjallajokull volcano still a possibility.
Nick Petford, a vulcanology expert at the University of Northampton, said:
Exactly the same thing happened in 2010 with the Eyjafjallajokull volcano. The main eruption was in April, but in March there was a fissure eruption which was a precursor to the much larger eruption.
He said scientists would now begin examining the volcano to try to detect any quakes deeper below the surface.
Those are pretty clear evidence that large amounts of magma are being stored within the volcano and that's a good indication it will explode.
The country's Met Office earlier reduced its ash warning level down from red to orange, after finding there was no threat to aircraft.
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