Iceland now on red alert for volcano eruption
Iceland has raised its aviation alert for the restless Bardarbunga volcano to red, indicating that some type of an eruption is imminent or in progress.
Thousands of small earthquakes have rattled the volcano deep beneath Iceland's Vatnajokull glacier in the last week, with activity picking up today after a lull the day before.
The eruption of Iceland's Eyjafjallajokul volcano in 2010 produced an ash cloud that caused international aviation chaos, with more than 100,000 flights cancelled.
The red alert is the highest warning on the country's five-point scale.
Scientists had planned to fly over the glacier later to look for changes on the surface but it was not clear if that would still take place.
Earlier this week authorities had evacuated several hundred people from highlands north of the Vatnajokull glacier as a precaution. The area is uninhabited but popular with hikers.
Aviation regulators have reformed policies about flying through ash since the Eyjafjallajokul volcano erupted, so a new eruption would be unlikely to cause that much disruption.
Seismologists say magma is moving under the glacier but so far has travelled horizontally at a depth of three to six miles. The volcano will erupt if the magma rises and melts the ice above.
Met Office vulcanologist Melissa Pfeffer said the amount of ash produced would depend on the thickness of the ice.
"The thicker the ice, the more water there is, the more explosive it will be and the more ash-rich the eruption will be," she said.
Iceland sits on a volcanic hot spot in the Atlantic's mid-oceanic ridge and eruptions have occurred frequently, triggered when the Earth's plates move and when magma from deep underground pushes its way to the surface.
