Just over a year after the eruption of Eyjafjallajökull shut down Europe’s skies, another powerful volcano has started up on Iceland.

At around 17:30 UTC on 21 May Grímsvötn began erupting. After punching through the glacial ice that it sits underneath, the volcano threw a plume of material some 20 kilometres into the sky, according to the Icelandic Met Office.

Grímsvötn last erupted in November 2004, says the Met Office, and is the country’s most active volcano.

Unlike Eyjafjallajökull, the eruption is not expected to have a major impact on European flights, as the current plume will likely drift northeast. But geologists are pretty excited by the latest rumblings from Iceland.

“Because it’s big!” explains University of Edinburgh volcanologist John Stevenson, on his blog. “This is the most powerful eruption in Iceland in over 50 years.”

He notes that the Eyjafjallajökull plume reached about 8 km, whereas this one is more like double that. “This is important because every extra kilometre of plume requires a much faster eruption rate.”

Other avid volcano watchers are also enthused. Former Nature editor Alex Witze notes (via twitter) that the Laki fissure on Grímsvötn was a real menace in the 18th century, when a huge volcanic event, far larger than this one, “spewed poisonous fog across Europe, killing tens of thousands”. (Check out her recent feature on sub-glacial volcanoes.)

Image: NASA satellite shot over Grímsvötn / NASA MODIS