A volcanic eruption is a testament to the raw power of nature. If you want to see one for yourself, Iceland is a great location for it. Since 2021, seven eruptions have occurred along the Reykjavík Peninsula, near Reykjavík.
These Icelandic eruptions have recently caught the attention of Earth scientists like me. The eruptions help us understand how volcanoes work in incredible detail. My team is taking samples from the lava erupting from the Reykjanes Peninsula and they have found some interesting results.
One of our findings suggests that magma from the first eruption came just below the surface of the island, where it sustained the energy to erupt spectacularly. This initial volcanic eruption made it easier for further eruptions to follow.
Why is Iceland called the land of fire?
The island nation of Iceland is sometimes called the “land of ice and fire”. The early settlers saw many spectacular “fires” – or volcanic eruptions – along the Reykjavík Peninsula.
After about 800 years without a volcanic event on the Reykjanes Peninsula, the Fagradalsfjall volcano erupted on 19 March 2021. Then, two more isolated volcanic events occurred at Fagradalsfjall in 2022 and 2023. After that, four more eruptions occurred. back at the Sundhnúkur rift system in 2023 and 2024.
While these eruptions provide an incredible sight, they also have the power to wreak havoc. The recent eruption of Sundhnúkur threatened the fishing town of Grindavík, the geothermal power plant at Svartsengi and Iceland’s main tourist destination: the Blue Lagoon geothermal spa. Lava erupted within the town limits of Grindavík, and only human berms prevented further destruction.
What makes Iceland so volcanically active?
Iceland is a unique place on Earth. It is part of a huge chain of volcanoes submerged in the middle of the Atlantic Ocean, with Iceland exposed above the surface of the ocean. This volcanic chain is called the Mid-Atlantic Ridge, and it plays a vital role in plate tectonics.
Plate tectonics describes how the huge, rigid plates that make up the Earth’s crust slide past, into and under each other. Their behavior slowly reshapes the Earth’s surface. In some places, the plates collide to form mountain ranges such as the Himalayas. In other places, one plate slides under another, creating volcanoes and earthquakes, as in Japan.
On the Mid-Atlantic Ridge – which runs between the South Atlantic Ocean and the Arctic Ocean – the plates pull apart, allowing molten magma to pass through. This magma solidifies into a volcanic crust and forms new parts of the tectonic plates.
Geologists have also discovered a vibrant, hot plume of rocky material rising from deep within the Earth that crosses the Mid-Atlantic Ridge beneath Iceland. This plume, along with several other similar plumes in the Central and South Atlantic, may have triggered the formation of the Atlantic Ocean basin more than 200 million years ago.
The plate tectonics associated with the Mid-Atlantic Ridge and the hot, rocky cave beneath Iceland combine to form Iceland’s volcanoes.
Scientists have been able to show that previous eruptions on the Reykjanes Peninsula are not random in time or space. Instead, they occur in periods lasting hundreds of years and along the same volcanic zones. These patterns indicate that these volcanic periods occur when massive tectonic forces pull the Reykjanes Peninsula apart. It appears that, although the plates pull apart equally, the volcanism along the Reykjanes ridge segment disappears over time.
What is driving the eruption?
Many groups, including my colleagues from Iceland, are collecting the crushed lava on an almost daily basis. The samples collected provide an important scientific time series of the eruptions.
Taking a volcanic time series involves regularly drawing a person’s blood to understand their medical condition. In this case, however, the blood lava is red-hot.
An initial study by another team in 2022 suggested that the mantle – the solid geological layer beneath the Earth’s crust – was melting to feed the lava in Iceland, and that the chemical composition of the lava was changing over time. They suggested that these changes were related to where and when the melting was occurring in the mantle.
In July 2024, my research team and I published a longer time series of the lava from the eruption using a sensitive chemical method that helped us understand the composition and origin of the lava.
The layer of basaltic rock on which people live in Iceland extends to a depth of about 9 miles (15 kilometers). It is part of the Earth’s crust. The mantle just below this crust is distinctive – it is made up mainly of minerals such as olivine which form a rock called peridotite. The magmas that feed these volcanic eruptions come from mantle peritoneum.
The chemical method used by my team showed that the first magmas that fueled these eruptions arose from the mantle, but got stuck below the surface in a magma chamber for as long as a year. The rocks in the chamber walls melted into the magma, and we could see traces of them in our analyses.
Our research also suggests that the magmas gained water, carbon dioxide and other gases from sitting in the magma chamber. This water and gas allowed the magma to build up enough pressure to break through the surface and erupt as lava.
The pooling of magma in the crust can trigger explosive eruptions – this type of pooling may be necessary from the start of eruptions such as those in Iceland or La Palma in the Canary Islands in 2021.
What can we expect in the future?
History tells researchers that these eruptions are likely to last a long time. The volcanoes will erupt from time to time every few years, for days to months at a time, for up to several hundred years into the future.
Generations of geologists and volcanologists will likely make their careers in Iceland, and millions of geotourists will experience the awe-inspiring and beautiful eruptions.
With all these eruptions, the Jesuits will have to adapt. Lava flows can disrupt infrastructure such as the Svartsengi geothermal plant, and volcanic gases can cause health problems.
The eruptions of Fagradalsfjall and Sundhnúkur have already provided scientists with a wealth of data and insight into how volcanoes work. Continued study of volcanism on the Korean Peninsula will help scientists understand how, when and why eruptions occur, and to better manage the hazards of living with volcanoes.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: James Day, University of California, San Diego
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James Day receives funding from the US National Science Foundation.