Mount Keilir, Iceland
© Promote IcelandMount Keilir, about 20 miles south of Reykjavik. Scientists said there was no immediate danger to the public.
Scientists in Iceland have said there are now "strong signs" that a volcanic eruption may be under way following several days of near-constant seismic activity near Mount Keilir about 20 miles south of the capital, Reykjavik.

"We are not saying we have signs an eruption has begun," Kristín Jónsdóttir of the Icelandic meteorological office told local media on Wednesday. "But this looks like the type of activity we expect in the run-up to an eruption."

Víðir Reynisson of the island's civil defence force told a mid-afternoon news conference it was "more likely than not" that an eruption - the first in the area since the 12th century - was about to begin, and could happen within the next few hours.

But Víðir said there was "no disaster going on and everyone can get on with their daily lives". There was no immediate danger, he said, although people should avoid travelling to the area on the Reykjanes peninsula.

Thousands of tremors measuring up to 5 on the Richter scale have been recorded on the peninsula during the past week. Freysteinn Sigmundsson, a geophysicist, said that if it came, the eruption could also be delayed by several days.

If magma reaches the surface, Freysteinn said, it is unlikely to be in the form of an explosion of lava and ash shooting into the sky, but rather what is known as a fissure eruption, in which lava emerges more slowly from a crack in the earth's surface.

That means there is unlikely to be a repeat of the chaos in 2010 when the six-day explosive eruption of the more southerly Eyjafjallajökull volcano caused huge disruption to international air travel, affecting as many as 10 million travellers.

"This event is completely different to Eyjafjallajökull," Freysteinn said. "It is very unlikely that it will disrupt air transport," he said. "This will probably be a lava eruption with little explosive activity."

Any lava flows near Mount Keilir are unlikely to reach populated areas, experts have said, but could interrupt air traffic to and from Keflavík international airport, which is about 12 miles from the main area of seismic activity and is on orange alert.

There is also a chance that road access to the airport could be cut off by lava flows, prompting authorities to draw up contingency plans to divert flights and passengers to the island's other airports.