Scientists Forecast End to Geological Unrest Near Grindavík

reykjanes eruption litli hrútur

Two geoscientists have predicted a need for increased magma accumulation beneath Svartsengi on the Reykjanes Peninsula to trigger a new intrusion. Utilising Icelandic Meteorological Office data, their analysis suggests that the current geological unrest near the town of Grindavík will conclude between July 1 and August 15.

Past predictions proved accurate

According to a recent forecast by two geoscientists, a greater volume of magma is now required to accumulate beneath the Svartsengi area on the Reykjanes Peninsula than before to initiate a new magma intrusion. The experts, volcanologist Haraldur Sigurðsson and geophysicist Grímur Björnsson, have observed a deceleration in magma accumulation and anticipate that the geological disturbances near the town of Grindavík will subside by late summer.

“Earthquakes, magma intrusions, and eruptions have plagued the residents of Grindavík since November 10, 2023, to this day,” the two scientists wrote on Haraldur Sigurðsson’s online blog. “When will these disasters end? When can residents return home and the fisheries resume operations in one of Iceland’s largest fishing ports? We believe that scientific data now available allow us to estimate when the movements of magma and eruptions in the Sundhnúkur crater row will cease.”

On the Channel 2 nightly news yesterday, reporter Kristján Már Unnarsson delved into these prognostications.

“They predict that the disturbances near Grindavík will conclude by late summer, that is, in four to five months. It’s worth recalling that during the Holuhraun eruption, which began at the end of August 2014, Haraldur boldly predicted that the eruption would end by the end of February or the beginning of March. He could hardly have been more precise, as the end of the eruption was declared on February 28. Therefore, there is reason to listen to him,” Kristján observed.

Forecast based on data from the Icelandic MET office

Kristján detailed how Haraldur and Grímur derive their forecasts from data provided by the Icelandic Meteorological Office. This includes a chart documenting five significant geological events since November, encompassing three eruptions and two magma intrusions that failed to culminate in eruptions. Utilising this data, the two experts have developed their own analytical chart to project when the current geological unrest will conclude.

A graph from the Icelandic MET Office
Icelandic Meteorological Office

“It shows how the magma inflow under Svartsengi has been gradually slowing. In the tremors in November, when everything was shaking, the magma inflow measured over 700,000 cubic metres per day. Since then, the inflow has steadily decreased,” Kristján commented.

A magma graph from Haraldur Sigurðsson's online blog

Kristján explained that the scientists believe this magma inflow follows a linear trend. Based on this trend, the two scientists predict that this geological unrest will conclude sometime between July 1 and August 15.

Reykjanes Eruption Imminent As Magma Nears “Threshold”

litli-hrútur reykjanes

Increased seismic activity on the Reykjanes Peninsula suggests an imminent eruption between Hagafell and Stóra-Skógarfell. A volcanologist at the University of Iceland predicts the eruption could start as early as today, potentially marking a continued pattern of frequent eruptions in the area.

Eruption expected over the coming days

Seismic activity near the magma chamber not far from the town of Grindavík on the Reykjanes Peninsula has increased, indicating that the volume of magma is reaching its threshold. In an interview with Vísir today, Benedikt Ófeigsson, Director of Seismology at the Icelandic Meteorological Office, expressed his concern about people staying in Grindavík but hopes they are ready to leave town quickly.

Speaking to, Þorvaldur Þórðarson, professor of volcanology at the University of Iceland, echoed Benedikt’s concerns, stating that he expected another eruption on the Reykjanes peninsula soon.

“There is no indication that magma is on the move, and the seismic activity we saw last night is likely due to tension in the crust. This, however, tells us that an eruption is close. A threshold is being reached. I said the other day that the eruption would come on March 1, and I’m inclined to stick to that prediction.”

Þorvaldur added that an eruption could begin today or Monday at the latest.

“We are close to having enough magma to lift the lid. We are within those uncertainty margins in terms of volume, and the land uplift has become significant enough that it is in a similar position as it has been before,” Þorvaldur stated, noting that all signs were pointing to an eruption between Hagafell and Stóra-Skógarfell. “However, it cannot be ruled out that a fissure might open further north or south, with the highest likelihood being on the Sundhnjúkar ridge,” Þorvaldur observed.

A pattern that could continue for months or even years

Þorvaldur expects this recent pattern of eruptions on Reykjanes – where eruptions occur every three weeks and last between one to three days – to continue over the next months or even years,

“It is possible that a major earthquake could interrupt this sequence of events, although, in all likelihood, this will simply continue,” Þorvaldur remarked, noting that there have been six eruptions in the Reykjanes peninsula in less than three years.

Þorvaldur suggested that the authorities should consider opening the town of Grindavík, the Svartsengi Power Plant, and the Blue Lagoon more quickly following the next eruption while urging caution and advising against staying or working in these areas when another eruption seems imminent.

As previously noted by Iceland Review, if an eruption were to occur near the Svartsengi area, it would be the fourth eruption since December of last year. It is highly unlikely that such an eruption, as it is confined to a small area on the Reykjanes peninsula, would impact travellers in Iceland.

Reykjanes Eruption Could be Short-Lived, Volcanologist Notes

Reykjanes eruption Iceland eruption

A volcanologist has described the ongoing Reykjanes eruption as typical for shallow magma chamber eruptions, where built-up pressure leads to rapid magma ascent followed by a quick decrease in intensity. The volcanologist also noted that there are indications that the current eruption may be short-lived.

Eruption in Grindavík unlikely

In an interview on the radio station Rás 2 this morning, volcanologist Þorvaldur Þórðarson characterised the ongoing eruption on the Reykjanes peninsula as typical for eruptions originating from a shallow magma chamber, where magma has been injected into a chamber over a significant period of time, causing pressure to build.

“Once that pressure becomes so great that it equals or exceeds the threshold of the chamber’s roof, it breaks, and the magma ascends very quickly. This extra pressure from the accumulation of magma drops rapidly, causing the eruption to decrease swiftly. This is actually a classic example of such eruptions.”

Asked about the likelihood of new vents opening on the fissure as activity diminishes, Þorvaldur believes the chances are “lower than higher.” 

“The risk continually decreases. In my view, there’s almost no chance of an eruption, for instance, in Grindavík, or in its immediate vicinity. However, there’s always a possibility that some craters might reactivate a bit further north. But it seems more likely to go in the other direction.”

Might be over before the weekend

In Þorvaldur’s opinion, it is not unlikely that the area from Eldvörp to Fagradalsfjall might experience more eruptions in the coming years, either on the Sundhnúka rift, along the line in Fagradalsfjall, or possibly slightly westward. “I believe this is not over, unfortunately. There’s an equal chance that we might see a repeat of these events in the coming years.”

When asked to predict the future course of the eruption, Þorvaldur replied that such a thing was difficult. “But many indications suggest that this will be a short eruption that could end within the next few days. Possibly even before the weekend.”

Magma Could Threaten Grindavík Again (and Again)

grindavík evacuation

Magma may start flowing into the dike underneath the town of Grindavík again days or months from now. The Icelandic town remains evacuated and experts say it is not clear when it will be safe for its residents to return to their homes. While an eruption near the town, located on the Reykjanes peninsula, is now considered less likely in the short term, a new phase of seismic activity may be beginning.

In late October, an earthquake swarm and uplift began on the Reykjanes peninsula near the town of Grindavík indicating magma collecting underground. The magma intrusion grew and filled a dike stretching beneath the town, leading authorities to issue an evacuation order on November 10 due to the risk of eruption.

A new chapter of activity

Magma inflow to the dike has likely stopped, according to a notice from the Met Office, and the chances of an eruption happening along the dike at this time have decreased. However, magma continues to accumulate just north of Grindavík, beneath Svartsengi, where a geothermal power plant and the Blue Lagoon are located. “The ongoing activity at Svartsengi, which began in October, is not yet over and a new chapter may have begun with an increased chance of a new magma propagation and, subsequently, increased likelihood of an eruption,” the Met Office notice states.

“[T]he dike beneath Grindavík was fed by magma accumulating beneath Svartsengi. It is likely that this sequence of events will repeat,” the notice continues. A new magma propagation would provide a warning in the form of earthquakes and ground deformation, which would be detected by equipment “several hours before the magma propagation is likely to pose a threat to Svartsengi or Grindavík.”

Timeline impossible to estimate

According to the Met Office, this pattern of magma accumulating beneath Svartsengi and flowing into the dike that stretches below Grindavík is likely to happen again, even repeatedly. However, it is impossible to estimate whether that will be “in the next few days or possibly after several months.”

Kristín Jónsdóttir, Head of the Volcanos, Earthquakes, and Deformation Department at the Icelandic Met Office, told RÚV it was not clear when it would be safe for Grindavík residents to return to their homes.

Chances of Eruption in Grindavík Diminishing

Svartsengi Grindavík

The most likely location of an eruption on Reykjanes is now considered to be north of Grindavík and east of Svartsengi Power Station and the Blue Lagoon, according to experts. The likelihood of an eruption has, however, diminished overall. The construction of lava barriers to protect the power station is ahead of schedule and while an evacuation order remains in effect, regulations on entering Grindavík for residents and business operators have been relaxed.

It has been a time of upheaval for the town of Grindavík (pop. 3,600), which was evacuated on November 10 amid powerful seismic activity. Earthquakes and the formation of a magma dike under the town have opened crevasses and damaged roads, homes, and infrastructure in and around Grindavík. An eruption is still considered a possibility, though the likelihood of one has diminished.

Grindavík eruption less likely

One of the reasons Grindavík was evacuated was that experts could not rule out an eruption in the town itself. Now, the most likely location of an eruption is considered to be between Sýlingarfell and Hagafell mountains, northeast of Grindavík and east of Svartsengi Power Station and the Blue Lagoon.

Data indicates that magma is continuing to stream into the magma dike that stretches below Grindavík and northeast from the town. However, some experts have suggested that the magma in the dike is partly solidified, though it would take months for it to solidify fully. While an eruption is still possible, it is considered to be less likely than previously believed. The likelihood of an eruption within the town limits of Grindavík is also considered less and less likely to occur.

Lava barriers ahead of schedule

The construction of lava barriers, which began around two weeks ago, is ahead of schedule, the Director of the Civil Protection and Emergency Management Department told RÚV. The barriers are to surround Svartsengi Power Plant and the neighbouring Blue Lagoon, and are expected to take 30-40 days to complete.

While an evacuation order remains in effect for Grindavík, authorities have relaxed restrictions for the town’s residents and businesses, who are permitted to enter the town in order to take care of their property and retrieve belongings. Some businesses have also begun operating once more during daytime hours. While some of the town’s water and power infrastructure sustained damage in the recent earthquakes, water and power are functional in much of the town and repairs are being conducted.

Iceland’s Parliament passed a bill yesterday to provide financial support to businesses in Grindavík whose operations are impacted by the evacuation. The support is intended to help businesses continue to pay out employee salaries over the coming months.

Askja Slowly Preparing for Eruption

Askja, Viti, Öskjuvatn, volcano

The land at Askja has risen 70 cm over the past two years, indicating that some 20 million cubic metres of magma are collecting under the volcano’s surface. Measurements show that the temperature of the site’s geothermal lake Víti has risen this summer. There are no signs of an imminent eruption at the remote highland volcano, however, and if and when one occurs, experts say it is unlikely to affect inhabited areas or air traffic.

Askja’s last eruption occurred in 1961 and gave clear warning in the form of strong earthquakes and a significant rise in geothermal temperatures. No such signs have yet occurred at the site despite the uplift and higher lake temperature, Kristín Jónsdóttir, head of the Icelandic Met Office’s Volcanos, Earthquakes, and Deformation Department, told RÚV.

Uplift also occurring at Torfajökull

While eruptions at Askja can produce ash like the Eyjafjallajökull eruption of 2010 that disrupted air traffic, Kristín says an effusive eruption is the more probable outcome and would most likely not impact inhabited areas or air traffic. An uncertainty phase is in effect for the area and authorities have discouraged travellers from bathing in Víti geothermal lake or hiking around Askja lake.

The Icelandic Met Office reported yesterday that uplift is also occurring at Torfajökull, a small glacier also in the Highland region. The uplift indicates that magma is collecting below the surface but no increased earthquake activity has been measured at the site. The last eruption at Torfajökull occurred in 1477.

Meanwhile, the Reykjanes peninsula’s third eruption in three years has officially ended.

Reykjanes Earthquakes: Uncertainty Phase Declared

The Department of Civil Protection and Emergency Management has declared a phase of uncertainty due to the ongoing earthquake swarm on the Reykjanes peninsula in Southwest Iceland. Six earthquakes over M3 were detected on the peninsula yesterday, with the strongest measuring M4.7. Specialists say earthquakes and uplift in the area are likely signs of magma collecting below the surface. There are no signs an eruption is imminent.

Likely magma is gathering below surface

“We have seen, since before the weekend, indications that expansion and uplift are occurring by Svartsengi similar to what happened in 2020,” Met Office Earthquake Hazards Coordinator Kristín Jónsdóttir told RÚV. “That is we think it is quite likely that we are seeing the beginning of magma collecting below the surface at Svartsengi and it’s of course not unthinkable that could end in an eruption, but it is still much too early to say.”

The 2020 activity Kristín is referring to was a period of uplift (land rise) by Þorbjörn mountain on the Reykjanes peninsula. The uplift ended without an eruption ever occurring. An eruption did occur on the peninsula last year, however, as many readers know, and it was preceded by weeks of powerful earthquakes felt across Southwest Iceland. Volcanologist Þorvaldur Þórðarson has stated there is a 50% chance of another eruption on Reykjanes this year.

Falling objects and landslides

Travellers and hikers on the Reykjanes peninsula are warned to stay away from steep inclines, where earthquakes can cause landslides or rockfall. The Civil Protection Department encourages residents in or near the active are to secure loose objects in their homes that could fall in the event of an earthquake, particularly those that could fall on individuals while they are sleeping. The Civil Protection Department website features earthquake preparedness information in English.

Read more about the geology of the Reykjanes peninsula.

A Difficult Read

Þóra Hjörleifsdóttir rithöfundur

Every New Year’s Eve for a decade, Þóra Hjörleifsdóttir made the resolution to write a book. It took a while, but in 2019, Magma was published – a harrowing story about how a young woman loses herself within the confines of an emotionally abusive relationship affected by the pornification of society.It was published in February, […]

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