REYKJAVIK Iceland's most active volcano erupted on Saturday, hurling a plume of ash and smoke far into the sky, which aviation officials were closely monitoring after another volcano shut European airspace for days last year.
Authorities banned flights close to the Grimsvotn volcano but an official said the eruption was not expected to affect European airline traffic at least for the next 24 hours.
The plume from the Grimsvotn volcano shot 20 km (12 miles) into the sky. The website of newspaper Morgunbladid said the eruption was more powerful than its last in 2004.
"We have closed the area until we know better what effect the ash will have," said Hjordis Gudmundsdottir, spokeswoman for the Isavia civil aviation authority which has imposed a flight ban of 120 nautical miles (222 km) around the area.
Iceland's Eyjafjallajokull caused chaos when it erupted in April last year. Authorities halted flights due to fears that dust and ash would get into aircraft engines and cause accidents after the cloud was blown into European air traffic lanes.
Grimsvotn lies under the Vatnajokull glacier in southeast Iceland, the largest glacier in Europe. When it last erupted in 2004 trans-Atlantic flights had to be re-routed south of Iceland, but no airports were closed.
Gudmundsdottir said the winds in the area were strong and that Isavia and the Icelandic meteorological office were coordinating with Volcanic Ash Advisory Centres (VAAC), which advise airlines about the movement of clouds of volcanic ash.
There are two VAACs near Iceland, in London and the French city of Toulouse.
"It can be a big eruption, but it is unlikely to be like last year," Icelandic Met Office geologist Hjorleifur Sveinbjornsson told Reuters, referring Eyjafjallajokull.
He said the plume from Grimsvotn was going to the north and that the office's forecast for the next 24 hours was that ash would not affect European airline traffic.
The volcano could erupt for several days, he added.
One positive factor for air traffic was that the ash from this eruption was heavier, whereas the ash last year was lighter and so drifted further.
Domestic airline Icelandair said no traffic had been affected. "We do not expect the Grimsvotn eruption to affect air traffic to and from the country in any way," said Icelandair communications director Gudjon Arngrimsson.
Pictures on local media websites showed a thick cloud of white smoke like a mushroom cloud over surrounding mountains.
"Grimsvotn is a very powerful volcano, so we're monitoring it closely, even if the last few eruptions have been harmless," University of Iceland geophysicist Pall Einarsson was quoted as saying on the website of Morgunbladid.
"We do not expect this to be a big one as it's coming from the same crater as the last three eruptions, which were all small," he added.
(Reporting by Omar Valdimarsson in Reykjavik, Patrick Lannin in Stockholm; Editing by David Stamp)