Explained: An Update on the Geological Activity in Reykjanes

svartsengi power plant reykjanes

Magma accumulation under Svartsengi on the Reykjanes Peninsula since the December 18 eruption has increased the risk of another eruption. The head of the Department of Civil Protection and Emergency Management warns that residents and businesses near Grindavík and Svartsengi should be prepared for possible short-notice evacuation.

What’s going on in Reykjanes?

Ever since the brief but powerful eruption in Sundhnúksgígar on the Reykjanes peninsula on December 18, magma has been steadily accumulating in the area once again. 

As noted on the MET Office’s website, there is still relatively low seismic activity in the area, mainly concentrated between Hagafell and Stóra Skógfell, where the centre of the magma dyke is located. Continuous seismic activity in Fagradalsfjall has persisted since December 18.

Land uplift is still ongoing in the Svartsengi area, which has been quite stable since the eruption on December 18. The ground has risen about 5 mm per day recently and is now about 5 cm higher than before the magma intrusion on November 10 and December 18 last year.

Model calculations, derived from deformation data (GPS and satellite imagery), indicate that the volume of magma accumulated in the horizontal magma dyke under Svartsengi since December 18 is now similar to the volume that previously flowed from the same area, forming the magma dyke that triggered the December 18 eruption.

This means there is an increased risk of a magma intrusion in the coming days. The MET Office notes that it is important to emphasise that magma intrusion can lead to a volcanic eruption and that the last eruption began with very short notice.

The MET Office issued an updated hazard map on January 5 and will reassess the map on Friday, January 12. 

Volcanic eruption on Reykjanes peninsula
Golli. The largest eruption in Reykjanes since activity began in 2019.

What’s the latest news from the Department of Civil Protection?

In an interview with Vísir yesterday, Víðir Reynisson, Director of the Department of Civil Protection and Emergency Management, stated that reports that the volume of magma that had accumulated near the Svartsengi area on the Reykjanes Peninsula had reached a similar volume as before the last eruption had altered the situation from a civil protection point of view. 

“We are always approaching the time when a magma intrusion could begin, possibly leading to an eruption. We have received all the warnings we are going to get. The next thing that happens is that a geological event will start,” Víðir observed yesterday. 

Víðir stated that if the MET Office gets indications that this geological event is beginning, evacuations will be initiated. “The entire area will be evacuated as soon as that happens. Therefore, residents of Grindavík and those working or staying near the Svartsengi area will need to be prepared to evacuate on short notice. Such decisions could be made very quickly,” Víðir explained. “It’s not time to evacuate yet, but that could change rapidly, in the next few days or even sooner.”

Asked about the advisability of resuming business operations in Grindavík, Víðir remarked that if companies are capable of initiating a speedy evacuation, they have been given permission to resume work. 

Is an eruption in Grindavík a possibility?

Yes, although it is not the most likely scenario.

Magnús Tumi Guðmundsson, a professor of geophysics at the University of Iceland, told Vísir yesterday that an eruption near Grindavík, or even in the town itself, could not be ruled out. 

Asked to comment on the likelihood of an eruption in Grindavík, Víðir stated that such a thing would be considered the most serious scenario. “It’s not the most likely scenario, but it’s not impossible. Therefore, we cannot take any chances and will not do so. We will evacuate the area entirely if this gets underway.” 

Víðir’s message to those in Grindavík is to be prepared to leave on short notice.

Rescue workers assist Grindavík residents
Rescue workers assist Grindavík residents during evacuations in November (Golli)

Will this affect travellers coming to Iceland?

No, it is highly unlikely. 

Throughout the previous four eruptions in Reykjanes, the Keflavík International Airport has remained open and so have the roads leading from the airport and into the capital area (with a few rare and very brief exceptions). 

Although there is reason for Grindavík residents and businesses, and those employed near the Svartsengi area, to be prepared for speedy evacuations, travellers visiting Iceland need not be concerned.

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