It seems like Fagradalsfjall is not the only volcano keen to erupt at the moment. Last summer, scientists predicted a possible eruption of Grímsvötn, a subglacial volcano located under the northwestern side of the Vatnajökull ice cap.
Water is accumulated in the glacial lakes of Grímsvötn
Last year, experts predicted that extensive jökulhlaups, a type of glacial outburst of floods in the Grímsvötn area, were likely to occur. Those might have been followed by an eruption—which did not happen. According to Vísir, it is more likely now that an eruption might follow, as even more water has accumulated in the glacial lakes—and more magma in the magma chamber under Grímsvötn.
Scientists believe that the Grímsvötn volcano erupts when large glacial floods follow large accumulations of water in the glacial lakes, putting pressure on the magma chamber. Then the magma breaks its way through to the earth’s surface when the pressure on the chamber decreases again, due to the water flowing down in glacial floods.
Maximum water volume since 1997
Currently, experts have measured high pressure on the magma chamber, as well as extensive amounts of water in the lakes. Scientists have now detected the most accumulation of water since 1996, when a large eruption and glacial floods occurred in the lakes.
Björn Oddsson, geophysicist and director of civil defense, explains, “There are indications that the ice dam, east of Grímsvötn, holding the water in and having dropped considerably after the eruption in 1996, has now risen. The lakes can now collect more water than in the past. Everyone is expecting a jökulhlaup now,” Björn adds, admitting that he thinks it is likely that the glacial flood will take place this year.
Grímsvötn is “overdue”
Björn describes the phenomena in a simpler way, comparing it to a shaken Coke bottle when removing the cap. The longer no glacial floods occur, the more likely an eruption will follow. He explains, “The magma chamber in Grímsvötn always collects more magma, so more magma is in the chamber now than last year.”
The geophysicist says that it is impossible to predict how big the eruption would be. The last eruption occurred in 2011, which was very big in scale; meanwhile, in 2004 it was smaller. On average, Grímsvötn erupts every ten years.
As of right now, it is not possible to determine how big the eruption could be. “This is unknown, but history tells us that it will be small to medium-sized in scale.” Due to Grímsvötn being located under a glacier, the eruptions are always explosive. Luckily, GPS meters will give the Meteorological Office good notice though before glacial floods begin and an eruption might follow.
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