Iceland's most active ice-covered volcano named Grímsvötn, recently showed signs of a possible eruption, leading experts to believe that it is gearing up for a potential explosion. The indications also prompted the Icelandic Met Office to change the volcano's aviation code from green to yellow.
Experts fear that an eruption may be looming, and it would likely cause a mild disruption to air travel.
Signs of Unrest in Grímsvötn
Signs of unrest were noted in the area, a telling sign that magma is swelling in the volcano's plumbing. Authorities changed the aviation color code based on the following indications:
- Seismic activities during the past month were recorded to be above average.
- Increased geothermal activity over the past months, such as deepening the cauldron in places around the caldera.
- The surface deformation is way more than the volcano's pre-eruption in 2011
- Magmatic gases were recorded in the geothermal emissions this summer
- Multiple datasets indicate that Grímsvötn volcano has reached a level of unrest comparable to previous eruptions
- The water level in the subglacial lake is similar to the level before the floods in 2004 and 2010, making it possible for floods in the coming months.
- Inflation of the volcano as magma moves into the plumbing system beneath it
- Increased thermal activities that cause the melting of ice
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Patterns of Grímsvötn Volcano's Previous Eruptions
Grímsvötn last erupted in 2011, spewing an ash cloud 12 miles into the air and grounding 900 flights.
A year before the Grímsvötn eruption, another Icelandic volcano called Eyjafjallajökull also erupted, causing more unrest and canceled around 100,000 flights. Eyjafjallajökull is smaller than Grímsvötn.
The 2011 Grímsvötn eruption was unusually large and powerful. The eruption has a devastating effect that ashes were spewed 20 kilometers from the atmosphere.
Based on patterns from Grímsvötn volcano's previous eruptions, an increased number of intense earthquakes lasting a few hours (one hour to ten hours) suggest that magma is moving towards the surface eruption is imminent.
Dr. Dave McGarvie, a volcano expert at Lancaster University, said that Grímsvötn has a significant eruption once in a century, like in 2011. Still, it also erupts smaller blasts once a decade.
'If Grímsvötn's past pattern of occasional large eruptions with more numerous smaller eruptions occurring in between continues into the future, then the next eruption should be a small one (given there was a large one in 2011),' he adds.
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The Icy Roof of the Volcano
The icy roof on the top of the volcano also suggests that its eruptions may be less catastrophic than other volcanoes.
This volcano has ice on its "roof." .The ash spewed out of the blast collides with 850 feet of ice and clumps up.
The ashes become wet and sticky and plummet into the air quickly. This also limits the disruption and damage. Ashes can travel to a few tens of kilometers from the eruption site. The scenario is better for Icelanders and air travel as it prevents the formation of ash clouds, Dr. McGarvie said.
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