Government officials on Friday evacuated the town of Grindavik, Iceland, warning that a volcanic eruption is imminent. Cracks appeared in town and snaked under buildings, splitting streets and pouring steam into the air above. And while magma hasn’t yet bubbled to the surface, experts agree it probably will soon.
The volcanic activity is occurring on the Reykjanes Peninsula, about 25 miles southwest of Reykjavik, Iceland’s capital. The peninsula represents 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.
While the volcanism lay dormant for nearly 800 years, it suddenly awoke in 2020 and was followed by the eruption of the Fagradalsfjall volcano on March 19, 2021. Volcanic coughs and sputters have occurred since, but a more prominent 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 fissure of magma squeezing between crustal rocks, is burrowed beneath the town of Grindavik. On Saturday, the Office stated that magma was probably within 800 meters, of or 2,624 feet, of the surface.
Initially, a barrage of earthquakes – including two over magnitude 5.0 and thirteen at or above 4.5 in the past week – was most concentrated about two miles northeast of Grindavik, a town of 3,300 on the janes 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, cluing scientists into the possible movement of magma. The ground has lifted up to about 3 feet in western Grindavik. The overall magma intrusion is estimated at 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 Thorkötlustadahverfi, a suburb of Grindavik, back “only to retrieve vital items, pets and livestock,” according to the Icelandic Met Office. Roadways to and from Grindavik remain closed. Iceland’s popular Blue Lagoon hot spring site is closed until at least 7 a.m. Thursday, at which point 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 south 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 Iceland’s Reykjanes Peninsula, the current center of volcanic and seismic attention, 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 out lava.
The new feature was named Geldingadalsgos and 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 that year.
Another eruption from a separate fissure of Fagradalsfjall took place on Aug. 3, 2022.
In early July this year, a new eruption began near Litli-Hrutur, part of Fagradalsfjall . It was about 10 times as big as the first two eruptions. It diminished by Aug. 5.