While there are fears of a new eruption in the volcanic fissure near Reykjavik, there are also increasing signs of impending eruptions at two other volcanoes.
Reykjavik – Grímsvötn is one of the most active volcanoes in Iceland. It lies in the southeast of the island under the Vatnajökull glacier. The volcano has two large craters, one of which is ten kilometers in diameter, and there are other smaller craters in it. On Thursday afternoon (January 4th), six earthquakes with a magnitude greater than one were measured within an hour at Grímsvötn. Icelandic volcanologist Thorvaldur Thórtharson believes the volcano is preparing to erupt.
Iceland volcano about to erupt: “It’s a miracle that Grímsvötn hasn’t erupted long ago”
“You have to be surprised that it hasn't erupted yet, because Grímsvötn normally erupts every ten years,” Thórtharson told the Icelandic newspaper Visor. The last eruption of Grímsvötn took place in 2011. “The eruption back then was actually unusually large, so the volcano may have taken a little longer to fill its reservoirs.” The alert level for Grímsvötn was temporarily raised from green to yellow. Thórtharson doesn't see a reason to give the all-clear yet. When asked how long it will take until the next eruption, he answers this: “I think days and maybe weeks, but not much more.”
The eruptions on Grímsvatn themselves are usually relatively small. But Thórtharson warns: “They start with a fair amount of energy and can cause an ash cloud that even reaches a height of thirteen kilometers.” The ensuing ash fall would be limited to the glacier itself. The eruption of the Eyjafjallajökull glacial volcano further east in 2010 led to significant restrictions on air traffic over Europe and North America. There were fears that volcanic ash could damage the jets' turbines and blind the cockpit windows.
If an eruption occurs, there is a risk of a huge tidal wave carrying tens of tons of glacial floe
Another risk is glacier overflow, which a volcano can cause: the hot lava melts large masses of glacier ice, which leads to a rapid rise in river levels. Huge blocks of glacier ice can be washed down the valley as ice floes.
In November 1996, a glacier run on the Grímsvötn caused a 600 meter wide and four meter high tidal wave, and ice floes up to ten meters high and weighing several hundred tons destroyed the bridges on the island's ring road. The total damage was between ten and 15 million dollars. The 2010 eruption of Eyjafjallajökull also caused a glacier run that was small compared to that at Grímsvötn.
South of Reykjavik the earth rises menacingly again
The volcano south of Reykjavik, which had already erupted once in December, is also causing concern: the ground is rising along the entire length of the magma vein, which filled in November and where a volcanic fissure opened in December. The ground uplift has actually accelerated significantly since the middle of the week. Volcanologists expect that the new eruption will occur again at the height of the magma fissure that opened on December 18th.
This would not endanger the neighboring fishing town of Grindavik, the geothermal power plant and the recently reopened thermal baths of the Blue Lagoon in neighboring Svartsengi. In the medium term, however, increased volcanic activity is expected across the entire Reykjanes peninsula, on the edge of which the capital Reykjavik lies.
A huge volcano is also drawing attention again in the north of Iceland
Loud Volcanoes.net New volcanic activity has also been registered in the Askja Caldera in the north of Iceland – a popular destination for vacationers: According to this, the ground there has risen by a good 70 centimeters since July 2022. The total elevation is therefore approximately twice as high as at Svartsengi.
Between 1875 and 1930, a violent, sometimes explosive series of outbreaks, the “Askja Fires”, occurred in the Askja region. The ashfall forced many residents of the eastern coast to emigrate. There was a smaller series of outbreaks in the 1960s. The crater sank at the turn of the last century, and since 2007 earthquakes have indicated that the magma chamber was refilling at a depth of three kilometers.
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