Infrastructure under threat

Iceland: Volcanic eruptions could last for decades

(Bild: Icelandic Coast Guard)

According to an international study, the recent volcanic eruptions in Iceland could last for decades. The country's most densely populated region and its vital infrastructure may be threatened for a long time to come.

According to the study, the recurring pattern of eruptions and dormant periods will probably continue for centuries, but the current series of eruptions is more likely to last for years or decades, the researchers report in the journal "Terra Nova".

The series of outbreaks began in 2021 on the Reykjanes Peninsula in the southwest of the island, only around 55 kilometers southwest of the capital Reykjavik. There have been five major volcanic eruptions since December last year alone. Lava flowed out of elongated cracks in the earth, which is why this type of eruption is also known as a fissure eruption. Some houses were covered in lava.

Last volcanic activity 800 years ago
A large part of the population of the North Atlantic island lives in the affected region. It is also home to the only international airport and several geothermal power plants that supply hot water and electricity for the country. According to the study, the peninsula was last volcanically active almost 800 years ago.

For their investigation, the researchers analyzed earthquake data from the past three years and took lava samples from several locations. They compared the liquid rock that flowed out of the earth at various locations in terms of its chemical and physical properties. In this way, they wanted to determine whether it came from the same magma chamber underground or from different chambers.

Interconnected magma system
According to the investigations, the magma actually has similar petrographic properties. This suggests a coherent underground magma system, the scientists write.

Together with the seismic data, they come to the conclusion that it is a moderately large magma accumulation at a depth of around nine to eleven kilometers, which extends over a width of ten kilometers. It formed between the years 2002 and 2020.

"Nature is never regular"
The research team concludes that the current series of eruptions could be the beginning of a long episode. But they cannot predict how long the series will actually last. "Nature is never regular," said co-author Ilya Bindeman, volcanologist and professor of earth sciences at the University of Oregon in the USA. "We don't know how long or how often it will continue over the next ten or even hundred years. A pattern will emerge, but nature always has exceptions and irregularities."

Iceland is located on the Mid-Atlantic Ridge, the tectonic plate boundary where the North American and Eurasian plates are moving apart. Volcanic eruptions are therefore frequent in Iceland, but the eruptions of the more centrally located volcanoes usually only last a few days or weeks, such as the eruption of the Eyjafjallajökull volcanic glacier in 2010. The fissure eruptions, on the other hand, can last much longer.