On November 10th, 2023, the Earth shook and a 14km magma-filled crack opened on the Reykjanes peninsula in Iceland. Threatened by lava flows, deep fissures and powerful earthquakes, 3,600 people were evacuated from the small town of Grindavík in the following months. With lava bubbling and seeping, the eruptions have not been visually severe but effects on local communities could go on for years.
“These types of lava flows move slowly, if you saw it, it looks red and incandescent, rubbly rock moving along at walking pace,” says Dr Michael Stock, assistant professor of geology at Trinity College Dublin. His research looks at the density of rocks from past eruptions, which act as “time capsules of the processes going on underground”. The patterns drawn from geological history offer insights into current events.
Stock explains that in most cases around the world, historical and geological records give an indication of how volcanic eruptions will play out, “but it’s hard to get a sense of what happens in Iceland because it’s so dynamic”. In such a volatile landscape the ground is constantly changing and recovering so the remnants of past events are wiped out before they can be studied. This means scientists have to come up with novel research approaches.
While Stock operates in the aftermath, Prof Chris Bean from the Dublin Institute of Advanced Studies captures specific moments in eruptions as they happen. “It’s really just shrinking the timescale down to the human,” he says.
Bean records sound produced by the shifting earth, something he compares to using a stethoscope. Much of his work takes place in the Galápagos Islands but he also uses sensors installed around Iceland and here in Ireland, recording and interpreting the sonic outputs of earthquakes and eruptions.
“It’s a matter of decoding and getting to understand what exactly these sounds mean”, he adds. The low-frequency crackling of breaking rocks indicates the ways that magma is rising to the surface: “Depending on how the [rock] breaks, the waves that travel away are quite different, they hold information”.
Detecting invisible patterns is a difficult task that requires acute listening and the employment of artificial intelligence: “The material is highly heterogeneous and [sound] is getting scattered and shredded as it travels. And that makes imaging very difficult because it’s like fog where all the little lights are getting scattered in the particles.”
The Earth’s crust is about 40km thick and Bean is especially interested in the upper reaches, decoding signals produced as magma reaches the surface. Knowledge of these signals might contribute to warning systems in volcanic regions: “We’re trying to better understand the processes that lead to volcanic eruptions”, he says, explaining that his approach is among many contributing to a collective understanding over a variety of scales.
“Some people are interested in the long-term hazard for a certain volcano when it might come alive again. We’re interested in when the thing is in play ... [when] we know it is likely to go in the next couple of weeks, days, hours, minutes. So it’s really in that last frame, decoding that and getting to understand what exactly these sounds mean.”
The last period of volcanism to strike the Reykjanes Peninsula was almost 800 years ago, and geologists say the area is entering a new phase of activity that could last from decades to centuries. “There’s no definitive answer for why volcanic activity follows these cycles”, says Stock, “but if we understand what’s happening in the lead-up to past eruptions we can help to monitor ongoing eruptions”.
Iceland sits atop the mid-Atlantic Ridge, which separates the North American and Eurasian tectonic plates. A powerful magma plume beneath the island produces an upwelling known as a hotspot that drives volcanic activity. The same hotspot was once situated beneath Ireland, which has a volcanic history of its own.
“The hotspot under Iceland made the Giant’s Causeway and Slieve Foye,” adds Stock, who describes Ireland as a “proto-Iceland” from 60 million years ago, “an analogue for processes that are happening deep beneath Iceland today”.
By accessing ancient data through geological records, scientists can make predictions on how an eruption will behave. They know that volcanic activity in Iceland will usually take a gentle course. Things were different during the 2010 eruption of Eyjafjallajökull because the event happened under ice, which cooled and shattered the rising magma.
Stock compares the phenomenon to “putting water in a chip pan”. In most cases, Icelandic eruptions are quite passive because the lava is highly basaltic, meaning it is not very viscous and flows very easily, Bean notes. “In some other environments where you see volcanoes exploding, that’s because the material that’s coming out of them is very viscous, very sticky, and it kind of plugs the thing up and then it lets go.”
It is this sort of violent eruption that sent volcanic gases and a large ash plume into the sky above Mount Ruang in Indonesia in April when lightning crackled through a towering ash cloud and 12,000 people were evacuated.
Volcanic eruptions can be simultaneously frightening and spectacular. Cat Gundry-Beck is an Irish photographer living and working in Iceland. She describes the sensation of flying over an eruption to photograph it: “I remember thinking to myself if this didn’t feel so surreal ... I would be terrified.”
There is an entire community of photographers in Iceland who chase volcanoes. When they gather on an eruption, Gundry-Beck says it can be “like a festival”. But things quickly change and she describes an event when a fissure opened right where she had been standing only moments before: “That was a very solemn experience ... this ground is now open, and there’s lava flowing everywhere.”
While Gundry-Beck captures breathtaking photographs of volcanoes for a living, she draws a sharp distinction between danger and beauty, specifically when people’s homes and livelihoods are threatened. Speaking about the recent eruptions on the Reykjanes Peninsula, she says it’s “important to work respectfully and tell people’s story in a sensitive manner”.
The social effect of volcanic eruptions can last years and remain culturally embedded for generations. What matters is the scale and location of these events, says Magnús Guðmundsson, professor of geophysics at the University of Iceland.
Guðmundsson describes the current eruptions as a social event since the effects are disproportionately high for the scale of volcanic activity. While eruptions themselves can be anticipated and mapped out by scientists like Stock and Bean, the social implications can be unpredictable even if historical records exist.
He explains how disaster was avoided on the Icelandic island of Vestmannaeyjar in 1973 when people were able to flee aboard the fishing fleet. If the event had been just a couple of days earlier, an easterly storm would have carried ash over the town and made for treacherous seas prohibiting the escape.
In 1875 a large explosive eruption spread fragmented rock known as tephra over northeast Iceland, covering farms and pushing settlers to North America. Just two years earlier a fifth of Iceland’s population was wiped out when their livestock were killed by gas poisoning from an eruption and supply ships were unable to make it through winter seas from Denmark. The eruption had wider climatic effects across Europe.
The Icelandic Meteorological Office keeps a close watch on volcanic activity, issuing warnings and advisories in advance of potential eruptions. In most cases, risk to life is minimal but the cohesion of tight-knit communities can be severely disrupted. Guðmundsson has a personal connection to Grindavík and is in regular contact with relatives there. “The people are asking, ‘will we return?’ The village has a good chance of surviving but it will take a long time.
“In the big scheme of things, this is the trauma that comes with being displaced and not knowing what the future will bring, that is very difficult for people”. While he recognises the challenges of living in the face of volcanic activity, Guðmundsson says it is something Icelandic people adapt to: “You sort of live with it ... this is our culture, and our culture is very much shaped by the land.”
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