Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific breakthroughs and more.
After 800 years of calm, volcanoes have awakened on Iceland’s Reykjanes Peninsula – about 56 kilometers (35 miles) south of the country’s capital, Reykjavik.
Since 2021, a series of eruptions have disrupted daily life in this densely populated area, leading to evacuationspower cuts and damage to infrastructure, as well as fueling fears of an event such as the eruption of Eyjafjallajökull, a large volcano about 80.5 kilometers (50 miles) to the southwest that caused an international travel crisis in April 2010.
Although there is no risk of a global calamity occurring, researchers are now warning that new scientific evidence suggests that eruptions originating on the Reykjanes Peninsula could continue for years or even decades. Prolonged volcanic activity could lead to further disruption and potentially force the long-term evacuation of Grindavík, a fishing town of more than 3,000 people that is also the gateway to Iceland. biggest tourist attraction — the Lagoa Azul geothermal pool.
“I think we need to prepare to give up on Grindavík,” said Valentin Troll, professor in the Earth Sciences department at Uppsala University in Sweden and lead author of a study to study about the eruptions, published Wednesday in Terra Nova magazine.
“It can still survive as a fishing port, with people coming and going. But people staying there, with the possibility of a very rapid onset of volcanic activity, I don’t think it’s recommended. What we think at this point is that eruptions will likely continue as we have seen over the past three years, and our results would support that.”
To be able to predict whether eruptions would continue and how future volcanic activity might occur, Troll and his fellow researchers took a novel approach, bringing together two separate branches of science that revealed a primary underground source of magma, or molten rock, fueling activity on the Peninsula. Reykjanes.
Hugh Tuffen, reader in volcanology at Lancaster University in the United Kingdom, who was not involved in the report, said the research makes a solid case for the frequency of eruptions in the coming years. “This study provides a useful synthesis of evidence on the history of eruptions on the Reykjanes Peninsula, the chemistry of the erupted lavas, and the depth and nature of the earthquakes,” he said.
“All evidence points to the establishment of a single magma reservoir beneath (the volcano) Fagradalsfjall, and that this reservoir can then fuel eruptions at different positions on the Reykjanes peninsula, depending on changes in stresses in the crust.”
A new era of volcanic eruptions in Iceland
Iceland, which is about the size of Kentucky with a population of nearly 400,000, has more than 30 active volcanoes that have become tourist attractions within the country’s stunning scenery.
The high number of volcanoes that are actively erupting or showing signs of unrest is due to the fact that the island is located on a border between tectonic plates (giant pieces of the Earth’s crust and upper mantle that move slowly), Troll explained, creating cracks that allow magma to rise.
“The Reykjanes peninsula is right at this plate boundary,” he added, “and it appears that we are now witnessing the initial part of a major eruption episode. This is a recurring phenomenon on the peninsula, with 800 years of pause or stillness, followed by 100 or 200 years of intense eruptions, followed by another period of silence. Scientifically, we are lucky to be able to observe this, but from a social point of view we are not, because it happens in a very populated part of the country and with a lot of infrastructure.”
There is now a vast system of barriers around Grindavík to protect the city, with lava pushing past it in many places, Troll said. A power plant is also in the area and supplies Keflavík International Airport, the country’s main airfield, situated at the tip of the peninsula. “If the power station is affected, we could experience power shortages at Keflavík airport in the long term. This could affect international travel,” Troll said.
However, he added, the probability of an Eyjafjallajökull-type event is quite small, because the situation on the Reykjanes Peninsula is different – the lava fields are shallow and eruptions in the last three years have not been remotely close to Eyjafjallajökull levels. .
Key magma reservoir revealed
The research team analyzed the issue from the point of view of geochemistry and geophysics.
First, the team used geochemistry to observe the composition of the lava and recognized a similarity between samples taken several kilometers apart. This discovery shows that all eruptions are fueled by a shared magma reservoir that lies 9 to 12 kilometers (5.6 to 7.5 miles) below the surface, rather than by different sources.
So scientists used geophysics to look at the distribution of a series of earthquakes linked to the eruptions and found a cluster of deep seismicity at exactly the same depth underground. “It’s just below a volcano called Fagradalsfjall, and this appears to be the main magma chamber or macro reservoir, supplying other volcanoes as well,” Troll said.
“In a way, this is good news, because it means we will have individual, smaller eruptions, probably for a while, but not many simultaneous eruptions across the entire peninsula,” he explained.
The combined use of geochemistry and geophysics is not frequent, but it can lead to educated guesses about how many eruptions might arise from a volcano, according to Troll.
“The strength of this study and what makes it really powerful is that we combined two fundamentally independent methodologies to come to very similar conclusions,” he said.
“Geochemistry says that the magma has the same origin and seismic tomography says that there is only one main reservoir at depth. Putting these two things together gives a lot of strength to our forecast.”
Seismic tomography is a process that tracks and analyzes patterns of seismic waves generated by earthquakes in order to detect and characterize features of the Earth’s interior as three-dimensional models.
Monitoring seismic activity
The study is interesting and the results are convincing, said volcanologist Einat Lev, associate research professor at Columbia University’s Lamont-Doherty Earth Observatory in New York.
“I think it’s great to see geophysics and geochemistry being used in synergy to answer important questions about Earth,” said Lev, who was not involved in the study. “The volcanology community understands that interdisciplinary collaborations are critical and it is definitely a direction we are working in.”
She added that the eruptions could in fact threaten Grindavík. “We have already seen that even if magma doesn’t erupt or lava doesn’t flow towards the city, inflation and deflation, as well as the fissures they create, threaten the stability and security of Grindavik’s infrastructure.”
Combining different types of evidence, such as geochemical information about lava and geophysical data from earthquakes, is quite new, and it’s exciting that they both agree, said Jessica Johnson, associate professor of geophysics at the University of East Anglia in the United Kingdom. , who also did not participate in the work.
Demonstrating that the magma is supplied by a shared reservoir has implications for the frequency of eruptions and their duration, she added.
“This means there is a large supply of magma that is easy to erupt, allowing eruptions to occur in the region for a long time,” Johnson explained.
“Unfortunately, because the storage region is quite large, it means it is harder to say exactly where the next eruption will occur. This is why everyone in the area needs to be prepared for continued eruptions.”
According to Lancaster University’s Tuffen, the study emphasizes the importance of ongoing monitoring efforts. Icelandic geoscientists and international collaborators are monitoring the frequency and intensity of seismic activity and ground deformation in real time. The approach allows you to quickly assess the likelihood of future eruptions as magma accumulates in the Earth’s crust and new paths open up.
For more news and newsletters from CNN, create an account at CNN.com
