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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Grindavík Awaits End of Land Uplift for Return Home

Grindavík

Grindavík residents cannot return home until the ongoing land uplift ceases. Despite geological challenges, including a newly formed 25.7-meter-deep hole, Grindavík’s business sector is showing signs of revival.

Waiting on zero

Earlier this week, Víðir Reynisson, Head of the Department of Civil Protection and Emergency Management, fielded questions from Grindavík residents on the news programme Torgið. When asked about the prospect of a homecoming, Víðir remarked that Grindavík residents would be unable to return home until land uplift — the geological process where the Earth’s surface rises due to tectonic activities like magma intrusion — in town ceases.

Víðir noted that the land was currently rising faster near the Svartsengi Geothermal Power Plant than before November 10, when the magma intrusion extended into Grindavík, necessitating the evacuation of the town. “This geological event is far from over,” Víðir observed.

According to Víðir, only when the land uplift had reached a zero point could any discussion of homecoming commence. “Only then can we possibly start counting some days until it can be declared safe to return home.”

A deep hole

Examples of how the ongoing land uplift is affecting Grindavík have been noticeable over the past few days. On Wednesday, a deep hole was discovered in one of the neighbourhoods in Grindavík. When RÚV arrived on the scene, Ármann Höskuldsson, a professor of volcanology at the University of Iceland, was conducting measurements:

“This hole exemplifies the cracks emerging in the area as the land shifts apart. Unlike solid rock, the soil doesn’t move in unison when it fractures, causing it to fill the cracks. The crack we’re examining is approximately 25.7 metres deep, reaching the water’s surface, which means it’s even deeper below the water,” Ármann explained. “Remarkably, the groundwater level here is at 25.7 metres depth, a significant depth for such cracks.”

The hole is part of an extensive fissure bisecting the town into eastern and western sections. Regarding the type of water at the bottom of the hole, Ármann was uncertain: “I haven’t tested it, but it’s likely just groundwater.”

Ármann expressed no alarm over the presence of groundwater in the hole. “Groundwater is a common feature beneath us, no matter where we are in this area … it’s not a cause for concern.”

Awaken, industry

Despite the challenges posed by holes, cracks, and other damages, Grindavík’s business sector is showing signs of revival. Fannar Jónasson, the town’s mayor, expressed optimism in a recent interview with Vísir.

“We’re seeing a variety of businesses expressing interest in reopening. With available housing and machinery for production and services, people are returning and taking advantage of these opportunities to keep their businesses afloat,” he stated.

Fannar emphasised the growing sense of community and mutual support in Grindavík.

“It’s great to see how supportive everyone is. Those working need access to food and services. There are also machine shops and wood workshops , among other businesses, which are reopening. So it is all interconnected, and life here is in its infancy, once again, ushering in what we hope marks the start of a positive era.”