The Grímsvötn volcano in Iceland is known to be the country’s most active, which is something as it is a seismological hotspot. The last time it had a major eruption came in 2011, when it ploughed ash 20 kilometres into the atmosphere. The previous year, Iceland’s Eyjafjallajökull erupted, which caused travel chaos across all of Europe.
The Grímsvötn volcano was actually more powerful than the Eyjafjallajökull, despite it causing less disruption, and experts are warning that it is gearing up for another explosion.
The volcano erupts every five to 10 years, and with nine years since its last eruption, scientists believe it could explode any time now.
Usually, an eruption is hard to forecast for scientists, but as Grímsvötn erupts relatively frequently, scientists have been able to pick up on the signs.
For starters, the base of the volcano begins to expand as it fills with magma.
This magma causes intense heating, which leads to the ice surrounding the volcano to melt fairly quickly.
Both signs have been noted in recent months, as well as an uptick in earthquakes.
Dave McGarvie, a volcanologist at Lancaster University, wrote for The Conversation: “A high frequency of eruptions at a volcano allows scientists to detect patterns that lead to eruptions (precursors).
“And if these are repeated each time a volcano erupts then it becomes possible for scientists to be more confident that an eruption is likely to happen in the near future.
“It is, however, seldom possible to be precise about the exact day.
“Icelandic scientists have been carefully monitoring Grímsvötn since its 2011 eruption, and have seen various signals that suggest the volcano is getting ready to erupt.
“For example, the volcano has been inflating as new magma moves into the plumbing system beneath it (think of burying a balloon in the sand and then inflating it).
“Increasing thermal activity has been melting more ice and there has also been a recent increase in earthquake activity.”
The reason eruptions at Grímsvötn cause less chaos than those at Eyjafjallajökull, for example, is because the former is covered in a thick layer of ice and sleet.
As the volcano erupts, the ash collects the meltwater, making it much heavier.
As a result, the ash and debris tend to drop out of the sky more quickly.
Mr McGarvie added: “The smaller Grímsvötn eruptions expend a lot of energy when they interact with water and ice at the surface.
“That means the resulting ash gets wet and sticky and so falls from the sky relatively quickly. Ash clouds therefore only travel a few tens of kilometres from the eruption site.
“This is a good scenario for Icelanders and also for air travel, as it prevents the formation of substantial ash clouds that could drift around and close off airspace.”