Eruption Alert Level Increased As Magma Accumulation Reaches 11 Million Cubic Metres

Eruption Alert Level Increased As Magma Accumulation Reaches 11 Million Cubic Metres

Published September 30, 2025

Photo by
Emma Ledbetter

Magma under Svartsengi reached 11 million cubic meters on Sunday, September 28. This means that the volume of magma has now reached the level that erupted in the same area during the last eruption. The likelihood of a new eruption increases with each passing day, reports RÚV.

The last eruption on the Reykjanes Peninsula occurred northeast of Stóra-Skógfell on July 16. Since it ended on August 5, ground uplift at Svartsengi has been steady, and magma inflow has been consistent.

“We believe we reached the threshold — that as much magma has entered the system as went out last time. The system is now ready, and the pressure is high enough that magma could reach the surface. That doesn’t mean it will happen immediately; it varies how much magma enters the system before something triggers an eruption,” says Sigríður Kristjánsdóttir, a natural hazards specialist at the Icelandic Met Office.

The Icelandic Met Office has now raised the alert level to the second-highest stage, which means increased monitoring and surveillance. An eruption is most likely to occur along roughly the same path as last time, somewhere between Sundhnúk and Stóra-Skógfell.

“It could happen today, but it is more likely to occur in a few weeks. It could also happen that magma inflow stops and everything stabilizes, or even shifts between systems on the Reykjanes Peninsula, causing an eruption somewhere else entirely,” Sigríður says.

Everything is currently calm, and there are no signs that an eruption is imminent.

“Models indicate that it is likely something will erupt before Christmas, because the upper thresholds are expected to be reached sometime in December. But the system and its behavior could change, which would alter all assumptions and require us to recalculate. As the situation stands now, it is most likely that something will happen before Christmas,”Sigríður says.


The image is from August 2022 eruption and is used for illustrative purposes only.

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