50% Chance of Another Reykjanes Eruption this Year, Expert Says Skip to content
Geldingadalir eruption lava
Photo: Jelena Ciric. Geldingadalir eruption site, July 27, 2021.

50% Chance of Another Reykjanes Eruption this Year, Expert Says

Volcanologist Þorvaldur Þórðarson reckons there is a 50/50 chance that an eruption will begin on the Reykjanes peninsula by the end of the year. It could occur on land, like last year’s Geldingadalir eruption, active between March and September of 2021, or out in the ocean near the Reykjanes coast. While last year’s eruption was minimally disruptive to the surrounding area, there is always the possibility that another could cause air pollution, ashfall, or disruptions to international flights through Keflavík Airport, Þorvaldur told RÚV.

Earthquake swarms on Reykjanes

Earthquake swarms occurred on the Reykjanes peninsula last week and over the weekend. The second swarm began on Sunday morning and included two earthquakes over M3 in magnitude. The activity has since calmed down, but Þorvaldur says it’s possible the earthquakes are a sign of magma moving under the surface. There are, however, no signs that an eruption is imminent.

At sea or on land?

Eruptions at sea carry different risks to eruptions on land, according to Þorvaldur. “If it’s a sort of small, neat tourist eruption like the one in Fagradalsfjall then it’s good to have it on land, but if it’s bigger and more powerful, then the situation is different, and there there is maybe more at risk both in terms of lava flow and also in terms of sulphur pollution,” he stated. “There is much more sulphur pollution from eruptions on land simply because eruptions at sea or underwater create a lot of steam, and this steam condenses in the plume and takes out the sulphur. If the eruption is on land then we don’t have so much steam and much less of the sulphur is removed immediately, so it falls to the ground or spreads further and causes pollution. That’s the downside of an eruption on land.”

However, an eruption at sea that breaches the water’s surface could cause significant ashfall on land across the Southwest region, including as far north as Hvalfjörður, Þorvaldur says. He adds that if an eruption does occur, it’s even possible magma would breach the surface in several locations at once.

Experts have stated that the Geldingadalir eruption likely marks the start of a period of increased volcanic activity on the Reykjanes peninsula. Read more about the peninsula’s geology.

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