Glacial Outburst Flood Has Begun in Grímsvötn

Vatnajökull Grímsfjall Grímsvötn Bárðarbunga Kverkfjöll Jöklar Jökull Vísindi

A glacial outburst flood has begun in Grímsvötn beneath Vatnajökull glacier, experts have confirmed. An M4.3 earthquake at Grímsfjall this morning alerted experts to increased activity at the site. While such floods are known to increase the likelihood of volcanic eruptions, there are no indications an eruption is imminent at the site.

In an interview with RÚV, Professor of Geophysics Magnús Tumi Guðmundsson confirmed the glacial outburst flood began several days ago in the highland region. Elevated water levels have already reached inhabited areas further south, but they are not significant. “There is more water in Gígjukvísl river,” Magnús Tumi stated. “However, this is not a big event, it just looks like the summer water levels. It’s not a lot and it’s equivalent to a small or medium-sized glacial outburst flood in Skaftá river.”

Strongest earthquake in a long time

The M4.3 earthquake that occurred just before 7:00 AM this morning is “noteworthy,” according to Magnús Tumi. He says it’s “the biggest one we know of there for a very long time.” The earthquake hasn’t been followed by others of a similar magnitude, however, and appears to be a one-off event.

What is a glacial outburst flood?

Grímsvötn is an active volcano located beneath Vatnajökull, Iceland’s largest glacier. It has the highest eruption frequency of all the volcanoes in Iceland, but is located far from any inhabited areas. The geothermal and volcanic activity at Grímsvötn causes regular glacial outburst floods, known as jökulhlaup. Such outbursts are triggered by geothermal heating beneath the glacier which causes ice to melt, and eventually be abruptly released from beneath the glacier, into the surrounding water systems.

Magnús Tumi says Grímsvötn is now in a period of increased activity, which typically lasts between 60-80 years. It last erupted in 2011.

Premature to Declare Official End of Eruption, Experts Caution

A volcanic eruption near Sýlingafell in 2023

Experts are in consensus that the volcanic activity on the Reykjanes peninsula has ceased, though an official declaration marking the end of the eruption is still pending. The Chief of the Suðurnes Police hopes that after today’s meeting with the Icelandic MET Office, the authorities will be able to lift the restrictions in Grindavík.

Important to proceed cautiously

In an interview with RÚV published this morning, volcanologist Ármann Höskuldsson stated that the eruption near Sýlingafell on the Reykjanes peninsula was over. Kristín Jónsdóttir, a department head with the Icelandic MET Office, agreed with his assertion; there is no longer any measurable volcanic activity in the area.

Nevertheless, Kristín cautioned that it was too soon to officially declare the end of the eruption given that the situation could change rapidly; it is important to proceed cautiously, especially given the proximity of the eruption site to critical infrastructure.

Magma accumulation resumed

As reported by IR yesterday, there are indications that magma accumulation has resumed beneath Svartsengi. Magnús Tumi Guðmundsson, a geophysics professor at the University of Iceland, told RÚV that this renewed magma accumulation at Svartsengi closely resembles the conditions prior to the Sýlingafell eruption.

“If the magma continues its upward movement into the chamber beneath Svartsengi, we may witness a similar series of events,” he noted. Magnús Tumi added that it could take weeks or months for this to occur, however, and there’s also a possibility that the process might cease entirely.

Hoping for a homecoming

Úlfar Lúðvíksson, the Chief of Police in Suðurnes, told RÚV yesterday that scientists would review new data this morning, with a meeting with the Icelandic MET Office being scheduled for 1 PM today.

“I expect that the meeting will involve a review of the risk assessment map and, of course, I hope for a change that will allow residents to return home,” Úlfar stated. He mentioned that such speculations had already started before the eruption completely subsided. “One is always hopeful, and we will lift these restrictions if we find that such a thing is warranted.”

As noted by RÚV, applications for rental apartments for residents of Grindavík through the leasing company Bríet opened today. The application deadline is 10 AM tomorrow. The aim is to allocate most of the apartments on the same day.