Authorities have already evacuated Grindavik in the country’s southwest after a series of tremors.
The town of Grindavik on the country’s southwestern coast was evacuated after magma shifting under the Earth’s crust caused hundreds of earthquakes in what was believed to be a precursor to an eruption.
“We are really concerned about all the houses and the infrastructure in the area,” Vidir Reynisson, head of Iceland’s Civil Protection and Emergency Management told the AFP news agency.
The town – around 40km (25 miles) southwest of Reykjavik – is located near the Svartsengi geothermal plant, the main supplier of electricity and water to 30,000 residents on the Reykjanes Peninsula, as well as a freshwater reservoir.
Grindavik is also near the Blue Lagoon geothermal spa resort, a popular tourist destination which closed as a precaution earlier this week.
“The magma is now at a very shallow depth, so we are expecting an eruption within a couple of hours at the shortest, but at least within a couple of days,” Reynisson said.
The most likely scenario would be a fissure opening in the ground near Grindavik.
“We have a fissure that’s about 15km [9.3 miles] long, and anywhere on that fissure we can see that an eruption could happen,” Reynisson said.
However, he did not rule out the possibility of an eruption on the ocean floor, which would likely cause a large ash cloud.
“It’s not the most likely scenario, but we can’t rule it out because the end of the… fissure goes into the sea,” he said.
The quakes and ground lift caused by the magma intrusion have already caused damage to roads and buildings in Grindavik and its surroundings.
A large crack also tore up the greens on the Grindavik golf course, an image widely shared on social media networks.
Iceland, which has 33 active volcanic systems, has declared a state of emergency and ordered the mandatory evacuation of Grindavik on Saturday.
Emergency shelters and help centres have opened in several nearby towns, but most Grindavik residents were staying with friends or relatives, media reported.
Three eruptions have taken place on the Reykjanes peninsula in recent years near the Fagradalsfjall volcano: in March 2021, August 2022 and July 2023 — all far from any infrastructure or populated areas.
The Earth’s crust has been fractured “so much over the past three years” by those eruptions, “helping magmatic fluids in finding their path faster”, said Icelandic Met Office’s (IMO) volcanic hazards coordinator Sara Barsotti.
Prior to the March 2021 eruption, the Reykjanes peninsula had been dormant for eight centuries.
Volcanologists believe the new cycle of increased activity could last for several decades or centuries.
Situated in the North Atlantic, Iceland straddles the Mid-Atlantic Ridge, a crack in the ocean floor separating the Eurasian and North American tectonic plates.
A massive eruption in April 2010 at another Iceland volcano – Eyjafjallajokull, in the south of the island – forced the cancellation of some 100,000 flights, leaving more than 10 million travellers stranded.