Iceland’s Volcanic Eruptions in Reykjanes Peninsula Returns After 800 Years, Could Last for Years or Even Decades

The most populated region in Iceland is entering a new volcanic era, which can reshape its landscape for years to come.

Heightened Volcanic Activities

Since 2021, Iceland has experienced eight volcanic eruptions which caused residents to flee from their homes. But geologists now warn that the worst is yet to come for the citizens of the Reykjanes Peninsula.

The Reykjanes Peninsula had been volcanically dormant for 800 years until it became active again during the Fagradalfjall Fires. In late 2023 and early 2024, new volcanic fissures were created near the town of Grindavik, where huge plumes of lava were pumped out onto the surface.

These eruptions have forced local authorities to declare a state of emergency. This region is home to 70% of Iceland's total population and is also the location of the country's only international airport and geothermal power plants.

The most recent volcanic activity from May through June also prompted residents and visitors from the Blue Lagoon geothermal spa, a famous tourist attraction, to evacuate for the third time in over two months. The eruptions can bring considerable risks for economic disruption, leaving evacuated communities uncertain of a possible return.

Finding Clues From Beneath the Ground

To understand why this region has suddenly become so active, an international team of experts from the University of Oregon and University of California analyzed lava samples and seismic data from the last three years of volcanic eruptions. The result of their study is published in the paper "The Fagradalsfjall and Sundhnúkur Fires of 2021-2024: A single magma reservoir under the Reykjanes Peninsula, Iceland?"

Led by petrology professor Valentin Troll from Uppsala University, the research team used geochemical and seismic data to investigate whether the magma of the initial eruptions from a single volcano in Reykjanes Peninsula from 2021 to 2023 had the same origin as the magma in the recent volcanic eruptions to the west.

Comparison of these eruptions provides strong evidence that the country will need to prepare for an episode of volcanic activities. They found out that Reykjanes Peninsula is located in an interconnected magma plumbing system which can feed the volcanoes with molten rock for decades to come.

Magma is mainly composed of eight elements and 50 various trace elements in different ratios. The unique combination of these elements helps differentiate one magma source from another. The "fingerprint" of magma can also be identified using isotopic analysis.

After analyzing lava rock samples from two different volcanoes on Reykjanes Peninsula, the research team discovered that they actually have similar fingerprints. This implies a shared magma storage zone below the region. Although the geologists have predicted the potentially persistent volcanic episodes in the country, they cannot precisely predict yet how long the episodes and gaps between each will last.

Iceland sits directly above the Mid-Atlantic Ridge, an underwater mountain system that serves as a boundary between the tectonic plates of North America and Eurasia. As these giant pieces of the Earth's crust drift apart, the molten rocks from the mantle squeeze their way up to the surface.

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