Iceland’s ongoing volcanic eruptions may continue on and off for years to decades, threatening the country’s most densely populated region and vital infrastructure, researchers predict from local earthquake and geochemical data. 

The eruptions on the Reykjanes Peninsula have forced authorities to declare a state of emergency, with a series of eight eruptions having occurred since 2021. This southwestern region is home to 70 percent of the country’s population, its only international airport, and several geothermal power plants that supply hot water and electricity. The most recent eruption in May through June triggered the evacuation of residents and visitors of the Blue Lagoon geothermal spa, a popular tourist attraction, for the third time in more than two months.

Although Iceland sees regular eruptions because it sits above a volcanic hot spot, the Reykjanes Peninsula has been dormant for 800 years. Its last volcanic era continued over centuries however, prompting scientists to predict the renewed volcanism to be the start of a long episode. 

Under an hour’s drive from the island’s capital city Reykjavík, the eruptions pose considerable risks for economic disruption, and they leave evacuated communities uncertain of a possible return.

An international team of scientists has been watching the volcanoes over the past three years. Analyzing seismic tomography imaging and the composition of lava samples, they’ve uncovered parts of the geological processes behind the new volcanic era. They predict the region may have to prepare for recurring eruptions lasting years to decades and possibly centuries. 

The researchers report their findings in a paper published June 26 in the journal Terra Nova. The project included collaborations from the University of Oregon, Uppsala University in Sweden, University of Iceland, Czech Academy of Sciences and University of California, San Diego. The work follows an earlier Nature Communications study of the initial Reykjanes eruptions in 2021.

Lava from the January 2024 Sundhnúkur eruption reaching the outskirts of the town of Grindavik. Photographed in April 2024.

Analyzing samples of lava rock from two different volcanoes in the peninsula, their similar fingerprints implied a shared magma storage zone below the peninsula. Imaging of earth’s interior based on local earthquakes also suggested the existence of a reservoir about 5.5 to 7.5 miles in the earth’s crust, the shallowest layer.

Although this marks the beginning of potentially persistent volcanic episodes in Iceland, the researchers can’t precisely predict yet how long the episodes and the gaps between each will last.

“Nature is never regular,” Bindeman said. “We don't know how long and how frequently it will continue for the next ten or even hundred years. A pattern will emerge, but nature always has exceptions and irregularities.”

Discussions are continuing on plans to safely drill into the volcanic sites to glean insights into the geological processes driving the eruptions. 

Because the volcanic activity is less volatile and explosive than eruptions in other countries, it provides a rare opportunity for scientists to approach fissures actively erupting lava, Bindeman said. He called it a “natural laboratory” both astonishing and chilling.

“When you witness a volcanic eruption, you can feel that these are the massive forces of nature, and you yourself are very small,” Bindeman said. “These events are ordinary from the geological scale, but from the human scale, they can be devastating.”