The government said that the eruption was considered to be “relatively small” and that the risk to populated areas and critical infrastructure was low. Fissure eruptions do not usually result in large explosions or significant columns of ash flying into the stratosphere, the statement said.
But the government said it was still advising people not to visit the site. The eruption site “is a dangerous area and conditions can change quickly,” the Department of Civil Protection and Emergency Management said in a statement on Thursday.
It warned that toxic gas can accumulate when the wind decreases, that new lava fountains can open with little warning and that accumulating lava can flow quickly across the ground.
The fissure is about nine miles from a major transportation hub, Keflavik Airport, and about 16 miles from the Reykjavik metropolitan area, the government said.
“We’ve been expecting an eruption somewhere in this area since the series of earthquakes started last weekend,” Katrin Jakobsdottir, Iceland’s prime minister, said in a statement. “We will of course continue to monitor the situation closely and now we also benefit from the experience gained from last year’s eruption.”
There is a long history of volcanic activity in Iceland, which has more than 30 active volcanoes. The country straddles two tectonic plates, which are divided by an undersea mountain chain that oozes molten hot rock, or magma. Quakes occur when the magma pushes through the plates.