Unusual activity has been recorded of one of Iceland's most feared volcanoes Hekla and geophysicists fear it could erupt causing four times more ash than Iceland's last big eruption.
Experts have found strange magma movement deep beneath the volcano, which has been dubbed 'Gateway to Hell' and think these could be the early stages of a huge explosion.
If it does erupt, planes could be grounded for days.
'No eruption has started in Hekla volcano. But it might start without any warning', Icelandic volcano expert Jon Frimann told Irish Weather Online.
'What is more interesting is that this does not seems to have started until few days ago.
'But if there is any earthquakes, noise or whatever coming from Hekla volcano it is going to appear on my geophone that is located about 16 km away from peak of Hekla volcano.'
University of Iceland geophysicist Pall Einarsson yesterday said that it couldn't be stated with any certainty that the activity was a signal of an imminent eruption.
Hekla is located around 70 miles east of Iceland's capital Reykjavik. It is in close proximity to the Eyjafjallajokull volcano, which erupted in April and May 2010. The volcano caused widespread disruption to European airspace and grounding thousands of flights.
See pictures of a volcano erupting in Chile...
Volcano in Chile grounds flights across the globe