Volcanic mountains

Iceland’s eruption could be the start of decades of volcanic activity

Less than a year has passed since lava stopped erupting from Iceland’s Reykjanes peninsula following the region’s first major volcanic explosion in nearly 800 years. But now the island is bleeding molten rock again. The start of a new eruption so soon after the turmoil of 2021 seems to underscore that this once dormant peninsula has awakened from its long slumber.

“This could herald the start of decades of occasional eruptions,” says Dave McGarvievolcanologist at Lancaster University.

The new eruption, which began to 1:18 p.m. local time on August 3 sent scarlet ribbons flowing from the base of a small mountain into the uninhabited valley of Meradalir. Located far from populations, volcanic bubbles probably pose little danger to the public, at least in the short term. And this relative safety allows scientists and tourists to marvel at the geological majesty and get excited about a possible onslaught of new scientific knowledge.

After all, every volcanic eruption here provides a “window into the abyss,” says McGarvie. The 2021 event yielded revelations about the personality of the Peninsula’s exuberant eruptions, from their physical behaviors to their quirky chemistries. This new eruption promises even more insight as the budding volcano forges the world’s youngest land.

It is still unclear how prolific or long-lasting the eruption will be; this information will only be revealed with more time and continued monitoring. But this week’s fireworks display strongly suggests the peninsula will become one of the most volcanically active parts of the planet for generations to come.

“I’m really excited,” McGarvie said.

A double volcanic invoice

The Reykjanes peninsula is located about 27 km southwest of the Icelandic capital, Reykjavik. It sits atop the continuously extending Mid-Atlantic Ridge, where the North American Plate to the west and the Eurasian Plate to the east gradually separate. Super hot, gaseous magma, which is less dense than the surrounding rock, can sometimes rise into the shallow crust by buoyancy alone, but all that regional stretching also creates cracks where molten rock can infiltrate.

The subterranean chaos of the peninsula seems to manifest itself in periodic outbursts of volcanism. Historical accounts and studies of ancient volcanic rocks show that periods of volcanic rest turn into loud seismic and eruptive awakenings in a cycle that is happened several times in the last millennia.

With the scarlet flashes just spotted yesterday, scientists are already busy collecting their first rock samples, including volcanologist Helga Kristin, pictured here (top) Seen below, crowds also gathered to take in the stunning scenes, watching the Earth forge new landscapes.

Although the region had been volcanically dormant for centuries, the tectonic breakdown occurring deep below meant that last year’s eruption was long in the making. And in recent years, multiple layers of magma have risen to the surface, indicated by the changing shape of the ground and swarms of earthquakes, says Tobias Durig, volcanologist at the University of Iceland. But for a time these magmatic serpents saw no sunlight – their escape was blocked either by the loss of their own upward momentum or because the resilient crust offered no escape hatch.

Nevertheless, as earthquakes began to increase in frequency and intensity from late 2019, scientists suspected that an eruption in the future seemed inevitable. This was confirmed in dramatic fashion on March 19, 2021, when lava began erupting from a 1,650-foot-long fissure in a valley in the Geldingadalur region. Hundreds of thousands of visitors flocked to the area to witness this eruption, which built a vertiginous cone of magmatic spattering during its eruption for six months, without causing damage to infrastructure or casualties.

Then, since late July this year, another cacophony of earthquakes and significant ground deformation have plagued the region, indicating the upward incursion of another magmatic sheet, according to the Icelandic Meteorological Service.

On July 31, a 5.5 magnitude earthquake struck the peninsula. This and other powerful tremors before the last volcanic outbreak may have been so-called trigger earthquakes, McGarvie says. The stress builds as the magma intrusion stretches the crust, until it fractures with a powerful jolt.

On August 2, the magma sat just half a mile below the surface. Yet that same day seismic activity and ground deformation seemed to decline. While this might suggest that the magma had more or less stopped dead, this sequence of events also resembled the same pattern seen just before the 2021 eruption, which was the longest in the country in 50 years. Iceland’s upper crust can often stretch like a rubber band, accommodating magma without cracking noisily. So the most recent calm may have been a precursor to an eruption – the calm before the magmatic storm.

On the other hand, there have been similar ups and downs in seismicity on the peninsula that have not ended in eruptions, says Tom Winder, a volcanic seismologist at the University of Cambridge. Further investigation is needed to determine if this pattern of sudden seismic silence is a reliable warning sign.

Yet on August 2, available data led the Icelandic Meteorological Office to state that the possibility of an eruption was “considered substantial”.

Just a day later lava fountains shouted to the sky from a crack only a few hundred meters away from the cone shaped by last year’s eruption.

The land of future fires

Like its predecessor, the new eruption is likely to pose little danger to humans. Flows are currently confined to a series of empty valleys, with no major infrastructure nearby. Water or ice masses are also absent, which can sometimes trigger a series of violent, ash-laden explosions. This is all good news for locals, especially in the nearby fishing town of Grindavík which has been riddled with earthquakes. Now that the eruption has started, the disruptive earthquake has almost gone.

“It’s still early, but it looks like the eruption will be similar to 2021,” says Evgenia Ilyinskayavolcanologist at the University of Leeds.

But similar does not mean identical. By local media reports, the lava is currently flowing with more vigor than it did during last year’s event. This could either mean that the valley fills up quickly, or that the eruption could run out of fuel more quickly, resulting in a much quicker end.

It is extremely difficult to predict how long the eruption will last or how much lava it may produce. Ground deformation reveals the volume of magma available to fuel the eruption in the near term, but it says nothing about additional surges that may arrive from below in the days to come. Will the lava remain confined to these valleys or will it travel farther? Will it reach the sea and produce pernicious plumes of noxious gases?

“It’s a bit like watching the first hours of a Tour de France stage and trying to predict the future winner of the yellow jersey from there,” says Dürig. In this case, however, he expects the eruption to follow a similar pattern to the 2021 magma showcase.

While this is indeed the start of a new era in Reykjanes volcanism, it is difficult to predict what this might mean for those living on the peninsula, and it is currently impossible to say where or when the next eruption will occur. could emerge. Not all new eruptions will necessarily be located far from population centers or vital infrastructure. Some might differ in style from the recent pair. Several eruptions can even occur at the same time. Scientists can extract only a limited amount of information from ancient volcanic rocks, the oldest of which are often buried under newer flows.

“There are surprises to be expected,” McGarvie said.

Either way, these ferocious fires ultimately benefit everyone: they offer scientists an unprecedented look at the connective tissue between the igneous abyss below and the lava-licked landscape above. Their efforts are helping to improve our understanding of the Earth’s innards, Iceland’s volcanic cadence, and the volcanic hazards of this peninsula.

“Here we have a fantastic natural experience,” says Ilyinskaya. “It will for sure lead to many scientific discoveries.”