Iceland Builds 'Volcano Wall' to Guard Against Eruption

Authorities in Iceland are building earth walls around the town of Grindavik and a nearby power station to divert lava flows if a much-anticipated eruption occurs.

The two locations sit on a peninsula to the southwest of the Nordic nation's main island, and nearest to an underground shaft of magma that has pushed its way into the Earth's crust. The Icelandic Met Office has said there was a "significant likelihood" of an eruption, but that adverse weather in the next few days would make it difficult to monitor the situation.

Scientists have been monitoring elevated tectonic activity since November 10, when a magnitude 4.1 tremor occurred followed by a burst of others. Since then, an average of between 1,500 and 1,800 earthquakes a day have occurred.

As well as magma pushing the ground up by as much as three centimeters (1.2 inches) in the region, a vertical magma intrusion has formed close to Grindavik in a weak point in the Earth's crust, where molten rock is thought to be half a mile or less from the surface.

Drone footage posted on social media on Sunday shows heavy-load trucks and diggers constructing the dike on the outskirts of the coastal fishing town, where around 3,400 people were evacuated last week. Grindavik is thought to be nearest to the vertical intrusion, and it is feared magma would flow towards the town in the event of an eruption.

Jon Thor Viglundsson, of the Icelandic civil defense agency, told Sky News on Thursday that while the earth walls would not stop the lava in its tracks, they had been shown to divert the molten rock away from buildings.

"You guide lava, you can't stop it," he told the news outlet. "You push up large amounts of earth. It's the only way to make a funnel to turn lava away."

However, Andrew Hooper, a geophysicist at the University of Leeds, in the U.K., told Newsweek that the eruption "could happen within the town itself, in which case ash and lava would pose a direct threat."

While the area where lava is expected to emerge is directly next to the town, it could also flow towards Svartsengi, a nearby hotspot home to a geothermal power plant. It is also near where there has been a "significant crustal uplift" caused by a horizontal magma intrusion.

A large dike is also being constructed around the power plant, officials confirmed to several outlets last week, in the hopes that an eruption would not disrupt the supply of electricity to the rest of Iceland including the capital, Reykjavik.

State broadcaster RUV reported on Sunday that 60 percent of the walls aimed at protecting the power plant had been built, along with conduits and canals to direct lava away from buildings and towards the sea.

Prior to that, Icelandic Justice Minister Gudrun Hafsteinsdottir told the outlet that equipment and materials that could fill as many as 20,000 trucks were being moved to site.

Asked about the possibility of other potential emissions from any eruption besides lava, Hooper said: "Ash is likely to be a very local phenomenon, close to the eruptive vent itself and the subsurface vertical magma sheet is far enough from Svartsengi that this should not pose a problem.

"On the other hand, the lava flows produced by an eruption could flow for miles and reach Svartsengi, so the wall is to protect it from that threat."

The last time a major eruption occurred in Iceland was in 2010, when the Eyjafjallajokull volcano erupted several times causing a massive ash cloud to spread over Europe and North America, leading to severe disruption to air travel.