Fagradalsfjall, Iceland’s active volcano that is causing a stir

Fagradalsfjall is a volcanic fissure vent and subglacial shield volcano located on the Reykjanes peninsula in Iceland. Lately it became active and erupted, which brought a very big impact according to different studies.

First and foremost, to understand a volcanic eruption we have to understand how and why it happens. This is because the magma that is found inside volcanoes and is generated from inside the earth, rises together with the gases that are also found inside the volcano. This generates a very large impact on the surrounding nature.

On 19 March 2021, the volcano erupted and remained active until December 2021, a fact that soon attracted tourists. The journal Nature published two studies, led by researchers from the University of Iceland, on the seismic activity and magma movements that occurred during the eruption and in the weeks leading up to it.

Nature is one of the world’s most prestigious scientific journals, founded by British astronomer Joseph Norman Lockyer. Its first issue was published on 4 November 1869.

Earthquake movement in Iceland

Between December 2019 and March 2021, the Reykjanes peninsula was rocked by a series of earthquakes, two of which reached a magnitude of 5.6, raising fears of an imminent eruption. 

The earthquakes are believed to have been triggered by the intrusion of dykes and the movement of magma beneath the peninsula. Minor damage to houses was reported from the 5.6 earthquake on 4 February. In the three weeks prior to the eruption, seismographs recorded more than 40,000 tremors.

Hard data

What does this data have to do with the volcano’s eruption? That’s where studies in the famous journal Nature come in. 

These data showed differences in what usually happens prior to volcanic eruptions, as the rates of ground displacement and the number of earthquakes usually increase prior to a volcanic eruption. In this case, a rather unusual decrease in both ground deformation and seismicity was observed in the days preceding the eruption. 

In a second paper published in the journal, Sæmundur Halldorsson and colleagues examined the lava ejected during the first 50 days of the eruption. These analyses showed that it came from a direct source of magma from the boundary between the Earth’s crust and mantle. The authors note that the erupted lavas changed over time. The change was that during the initial phases of the eruption, the lava came predominantly from near the crust-mantle interface, but during the following weeks the composition changed, indicating that it came from magmas generated at greater depth.

These findings demonstrate that the magma storage zone near Moho is an extremely dynamic environment, where magma mixing occurs on incredibly short timescales. This demonstrates how quickly magma bodies can form in real time.

Care tips

  • Here is some advice on what to do and how to act at a time like this.
  • First of all, stay calm and avoid panic. During an eruption, if you are very close to the crater, stay away from the volcano, do not go towards it. Also stay away from valleys and rivers: mud or lava flows could flow down them.
  • Gather your family quickly, especially children and the elderly, who are the most vulnerable in times of panic.
  • Seek shelter indoors and stay there until the phenomenon stops. If you cannot find shelter, try breathing through a cloth dampened with water or vinegar: this prevents the passage of volcanic gases and dust. Also, protect your eyes by closing them. Protect your eyes by closing them as much as possible.
  • Remember that heavy ash falls can cause total darkness: therefore, do not attempt to drive vehicles, as the risk of accidents increases due to the darkness; moreover, the vehicle may be damaged by ash entering the engine.
  • When you leave your house, turn off the electricity, turn off the water, gas and telephone and lock your house tight to avoid accidents and looting. If you have a water well, cover it well.
  • Be especially careful in the valleys that descend from the volcano because they can be the route of fiery clouds, mudflows, avalanches and floods, which sweep away everything in their path.

Fortunately nowadays it is a very nice tourist destination to visit, always accompanied by a professionally trained guide for these occurrences.

Posted in Iceland.