Iceland’s youngest volcanic eruption started at Fagradalsfjall volcano on Reykjanes peninsula at the end of March, 2021. And now, it is still going strong and lava flow has even increased. The Fragradalsfjall eruption is the first eruption in almost 800 years on the peninsula.
On average, volcanic eruptions take place in Iceland every four to five years. Iceland has many active volcanic systems due to its location on the Mid-Atlantic Ridge and over a hot spot. Of Iceland’s 30 active volcanic systems, 13 have had eruptions since the settlement of Iceland in 874 AD.
With so many active volcanoes, you might wonder which ones are overdue for an eruption. In this article, we will present a short overview of three Icelandic volcanoes that are ready to erupt: Hekla, Katla, and Grímsvötn.
Hekla
Mt. Hekla is Iceland’s most famous volcano, and with 23 eruptions since the settlement of Iceland, it is very active. The volcano has produced one of the largest volumes of lava of any in the world in the last millennium, around eight cubic kilometres.
Hekla eruptions are diverse and difficult to predict. Some are very short (a week) and others can last months or years. Hekla eruptions are potentially dangerous and multiple hazards can occur, like tephra emissions, lava flow, ash, and flooding due to melting of snow.
Its last eruption was in 2000, and this lasted for 11 days, from February 26 to March 8. The actual plume of ash, gas, and water vapour was 10-12km high and did not last long. Hekla’s most recent major eruption took place from 29 March, 1947 until 21 April, 1948. That eruption involved a volcanic plume of 30km high.
Since 1970, the volcano has erupted at intervals of about ten years (1970, 1980-81, 1991 and 2000). This is one reason why the volcano is now considered to be “overdue,” as the last eruption occurred more than 20 years ago.
The more time is between eruptions, the more explosive Hekla’s next eruption will be. Measurements made at Hekla point toward a build-up of magma pressure which will result in a bigger eruption than its last two eruptions.
Because Hekla eruptions are unpredictable, and because of the potential hazards, there’s risks for hikers and sightseers in the area. They might not be warned in time in case of a sudden eruption. At close-range, an eruption of Hekla would produce a variety of lethal hazards, including lava fragments, ash, and gas.
Katla
Katla is Iceland’s largest volcano, and it is one of the most active volcanoes in Iceland. On average, it erupts every 50-100 years; in all 20 times since the 9th century, when Iceland was first settled. There have not been any large eruptions since 1918 which some people interpret to mean that it’s overdue.
Katla is completely covered by a glacier. This means that when there’s a big eruption, the lava and ice make for a pretty violent show. But if the eruption isn’t very big, it might not even breach the surface of the glacier. For instance, scientists are fairly sure there were minor, pressure-relieving volcanic events in 1955, 1999 and 2011, but there’s no way to be sure.
If Katla erupts, it could be a devastating volcanic eruption, a small one that is just enough to cause some floods, or it could be nothing at all. Historically, Katla has had eruptions measuring between four to six on the Volcanic Explosivity Index.
Fun fact, Netflix will soon release its first-ever original series from Iceland, named Katla. The eight-part series takes place in Vík and covers the events one year after a violent eruption of Katla.
Grímsvötn
Of Iceland’s 30 active volcanic systems, the most active one is Grímsvötn. As Iceland’s most frequently erupting volcano, it erupted about 65 times in the past 800 years.
Grímsvötn is located in Vatnajökull National Park, which contains Europe’s biggest glacier, and is completely subglacial. Its most recent eruption was in May 2011, which involved a 17km-high ash plume.
Eruptions at Grímsvötn take place at variable intervals and are different in size. Before the major eruption in 2011, there were small eruptions in 2004, 1998, and 1983.
There is one overarching pattern, though: every 150-200 years, a large eruption will occur, and in between there will be a smaller eruption about every decade.
Since the eruption in 2011, scientists are keeping a close eye on Grímsvötn, and their data suggests the volcano might be erupting soon. There have been more earthquakes in the area and heightened thermal activity has been melting ice. Based on Grímsvötn’s pattern, the next eruption should be a smaller one, since the eruption in 2011 was a large one, but only time will tell if this is really the case.
