Icelandic authorities are working on a plan to protect the evacuated town of Grindavik from a volcanic eruption, Sky News has been told.
Scientists currently believe the most likely site for magma to break through the surface is a short distance from the town, and it could flow towards houses.
But Almannavarnir, the Icelandic civil defence, said earth walls could be built to divert a river of molten lava away from the town.
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Jon Thor Viglundsson, from the authority, said the technique had been tested in recent eruptions elsewhere.
“So this we will try,” he said. “You guide lava, you can’t stop it. You push up large amounts of earth. It’s the only way to make a funnel to turn lava away.”
The magma is most likely to erupt between one and 1.5 miles northeast of the town, according to the Icelandic Met Office.
But the high-risk zone is on a slope and exactly where the magma breaks through will determine whether the lava flows south towards the town or north towards a power station, where a defensive wall up to eight metres high is already being built.
This map shows Grindavik, with the red shaded box indicating the area an eruption is most likely
Salome Jorunn Bernhardsdottir, a natural hazards specialist at the Met Office, told Sky News scientists were modelling different possibilities.
“It’s highly dependent on the contours,” she said. “The flow could go north or south.
“So, what teams have been doing is mapping out different scenarios, with different flow rates to see how effective barriers would be in diverting the flow.”
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The magma is currently believed to be at a depth of around 500m along a nine-mile line that passes close to Grindavik.
Dr Bernhardsdottir said the molten rock appears to be cooling and hardening in places.
But magma continues to build up in the area where an eruption is most likely.