Iceland sought to temper concerns that an imminent volcanic eruption would wreak widespread havoc on European aviation as happened in 2010.

An eruption is expected within days at Grindavik, a small fishing town in the country’s southwest, with a 15-kilometer (9-mile) magma tunnel underneath the town. The level of disruption to travel is dependent on whether magma emerges on land or in water, with the latter more likely to generate an explosive event and shoot ash up into the atmosphere.

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“The latest activity indicates that magma would most likely come up north of the town and that the likelihood of an ocean eruption has decreased,” Birta Lif Kristinsdottir, team leader of aviation weather services at Iceland’s Met Office, said by phone.

Three eruptions have occurred in the area since 2021, all of them fissure eruptions with lava flowing rather than spewing ash. Those contrast with the events of 2010, when volcano Eyjafjallajokull that sits under a glacier erupted in an explosion that released a plume of ash so vast that it grounded air traffic across Europe for weeks, resulting in the cancellation of 100,000 flights and affecting over 10 million people.

At the time, the International Civil Aviation Organization, ICAO, had rules which prohibited flying though airspace containing ash particles or affected by an ash forecast. The concern was that abrasive, silica-based material from volcanoes could clog engines and scar windshields.

Those rules were changed in 2014, leaving the decision on whether to fly to airlines, said Arni Gudbrandsson, senior air traffic management expert at the local air navigation service Isavia ANS.

“I would expect that under the new arrangement, any interruption will be less extensive than in 2010 if an explosive eruption were to happen,” he said over phone.

Still, weather service AccuWeather warned flight disruptions should not be ruled out, with Chief Meteorologist Jonathan Porter urging people traveling to and from Europe over the next few weeks to “closely monitor developments in Iceland.”

“Travelers will need to watch out for a potential cascade of flight cancellations and delays,” he said in an emailed statement.