By Johannes Birkebaek
COPENHAGEN (Reuters) – A seismic swarm has hit the Reykjanes peninsula in southwest Iceland with more than 5,500 small earthquakes in the last three days, raising the prospect of a volcanic eruption, the country’s meteorological office (IMO) said on Friday.
Located between the Eurasian and the North American tectonic plates, among the largest on the planet, Iceland is a seismic and volcanic hot spot as the two plates move in opposite directions.
While quakes are a daily occurrence in Iceland, the latest swarm was more extensive than usual.
“These earthquakes are a warning sign, a part of a longer-term story that we know we’re entering a build-up phase to the next (volcanic) eruption,” IMO Service and Research division head Matthew Roberts told Reuters.
The quakes originated at a depth of up to 5 km (around 3 miles) and were caused by a long-term accumulation of magma that has been building pressure and is now slowly drifting towards the surface of the earth, he added.
Earlier this year a volcano erupted in an uninhabited part of the Reykjanes peninsula after intense earthquake activity, the third such event in the region southwest of the capital Reykjavik since 2021.
A fourth eruption could now be developing, the IMO said, although predicting the timing of volcanic outbreaks is difficult.
“From my perspective as a scientist and someone who’s been following this activity very closely, I would say that an eruption within the next 12 months is likely,” Roberts said.
The strongest of the earthquakes had been measured at a magnitude of 4.5, and around 15 tremors were at 3.0 or stronger, the IMO said.
Earthquakes with a magnitude above 2.5 can often be felt by humans, according to the Michigan Technological University.
Grindavík, a fishing town on the peninsula with around 2,000 inhabitants is the town closest to the seismic activity.
(This story has been refiled to fix the spelling of ‘unusual’ in paragraph 3)
(Reporting by Johannes Birkebaek, editing by Terje Solsvik and Toby Chopra)