Icelandic officials have evacuated the town of Grindavik, warning that a volcanic eruption is imminent. Cracks have appeared in the earth there, snaking under buildings, splitting streets and pouring steam into the air. And while magma hasn’t yet bubbled to the surface, experts say it probably will soon.
The volcanic activity is occurring on the Reykjanes Peninsula, about 25 miles southwest of Reykjavik, Iceland’s capital. The peninsula is where the North American and Eurasian tectonic plates pull apart, allowing magma to bubble up to the surface periodically in a long history of eruptions.
The volcanism lay dormant for nearly 800 years, until it suddenly awoke in 2020. Then came the eruption of the Fagradalsfjall volcano on March 19, 2021. Volcanic coughs and sputters have occurred since, but a bigger eruption may be inevitable in the days ahead.
In fact, Iceland’s Meteorological Office warned Monday of a “significant likelihood of a volcanic eruption in the coming days.” It’s believed that a “dike intrusion,” or a fissure of magma squeezing between crustal rocks, is burrowed beneath Grindavik. On Saturday, the Met Office said the magma was probably within 800 meters, or 2,624 feet, of the surface.
Initially, a barrage of earthquakes — including in the past week two over magnitude 5.0 and thirteen at or above 4.5 — was concentrated about two miles northeast of Grindavik, a town of 3,300 on the Reykjanes Peninsula. It’s believed that’s where the upwelling of magma is.
Over the past 72 hours, the quakes have slowly migrated to the southwest, alerting scientists to the possible movement of magma. The ground has also lifted as much as about three feet in western Grindavik. The overall magma intrusion is estimated to be about 10 miles long, and continues southwest into the sea. About 100 earthquakes are still rattling the region every hour.
On Sunday, police allowed displaced residents of Thorkotlustadahverfi, a suburb of Grindavik, to return home “only to retrieve vital items, pets and livestock,” according to the Met Office. Roadways to and from Grindavik remain closed. Iceland’s popular Blue Lagoon hot spring also is closed until at least 7 a.m. Thursday, when a decision to reopen or stay shuttered will be made.
Iceland is no stranger to earthquakes and volcanoes. In 2010, the eruption of Eyjafjallajokull, on Iceland’s southern coast, ejected 330 million cubic yards of material and spewed ash 30,000 feet high. The ash plume forced the closure of most of Europe’s airspace for the better part of a week.
To the southwest, an entirely new island — Surtsey — emerged out of nowhere after an undersea volcanic eruption reached the ocean surface on Nov. 14, 1963. The eruption continued until June 5, 1967, when the island was 1.68 miles wide and 509 feet high. Wave action since then has eroded much of the island.
In the case of the Reykjanes Peninsula, the parent Fagradalsfjall volcano had remained quiet for 6,300 years until December 2019. That’s when a swarm of earthquakes, including a pair of magnitude-5.6 tremors, shook the peninsula. An even larger 5.7 quake struck on Feb. 4, 2021, causing damage. On March 19 that year, a 2,000-foot-long fissure opened up, oozing lava.
The new feature, named Geldingadalsgos, is considered a possible new shield volcano — a broad volcano with gently sloping sides. Several other cracks opened in April 2021, but only one remained active through May of that year.
Another eruption from a separate fissure of Fagradalsfjall took place on Aug. 3, 2022.
Then in early July of this year, a new eruption began near Litli-Hrutur, also part of the Fagradalsfjall volcano. It was about 10 times as big as the first two eruptions. It diminished by Aug. 5.
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