Experts worried by volcanic tremors

A huge Icelandic volcano is showing signs of activity that could disrupt air traffic, experts warn. There have been more than 500 tremors at Katla in the south of the country during the past month.

An increase in activity since July has been causing concern.

The last major eruption at the volcano in 1918 caused a large glacier meltdown that swept icebergs into the ocean.

Significant activity at Katla - which has a 10km crater - usually occurs every 40 to 80 years.

It is feared when it does eventually erupt, it could be the most powerful volcano activity the country has seen in almost a century.

Volcano expert Andy Hooper from Delft University said it was difficult to predict if and when Katla would erupt.

However, he said that the implications for Iceland if an eruption did occur would be "major".

"Because of the glacier on top, massive amounts of ice would melt, washing away the roads.

"There could also be a big ash fallout on people living in the area and that will affect the farms," he said.

"If Katla erupts, it will erupt higher [than recent volcanoes] and that means the ash will stay around longer - that could impact on air traffic."

Iceland's Met Office website warned there was no imminent threat but that "given the heightened levels of seismic activity, the situation might change abruptly".

Last year, eruptions at Eyjafjallajkull volcano disrupted air traffic for weeks.