Iceland's most active volcano may have spent most of its energy in the intense initial blast and could quieten down quickly
The eruption of the Grimsvötn volcano was so intense over the weekend that it may quickly quieten down and cause only fleeting disruption to air travel across Europe.
The volcano erupted on Saturday with a huge explosion that sent a plume of ash 20km into the sky. At the time, the volcano was blasting roughly 100 times more material per second into the atmosphere than was released from the Eyjafjallajökull volcano last April.
But the initial force of the blast means the volcano might have spent much of its energy already, at least for the latest eruption.
"The gigantic initial volcanic plume suggests that it may exhaust itself and cease quicker than the Eyjafjallajökull eruption," said Gillian Foulger, professor of geophysics at Durham University. The Grimsvötn eruption is believed to be the most powerful in Iceland in more than 50 years.
Measurements of the plume suggest the most violent phase of the eruption may already have passed. On Monday, local weather radar operated by the Icelandic Meteorological Office tracked the plume to a height of 10km, though it occasionally rose to 15km.
The Met Office planned to send balloons carrying instruments into the atmosphere to measure ash concentrations and particle sizes over western Scotland, but early attempts were thwarted by high winds.
Grimsvötn is the most active volcano in Iceland and usually produces large particles of ash that are too heavy to carry far by the wind. The latest eruption is more serious because it has forced ash high into the stratosphere where commercial airliners cruise.
In April, scientists at the Universities of Copenhagen and Iceland concluded that aviation authorities were right to ground aircraft last year, following an independent investigation into the ash particles produced by the Eyjafjallajökull eruption. The group noted that the particles were hard and sharp enough to abrade windows and aircraft bodies, and could melt inside jet engines, causing them to stall.
"If this is Grimsvötn blowing its top during an intense but short eruption, then activity will start to diminish in a few days, perhaps a week. More worrying for western Europe would be if this heralds the start of a sustained and lengthy explosive eruption that could last a month or two," said Dr Dave McGarvie, a volcanologist at the Open University.
"This eruption has started with much more vigour and violence than the two previous eruptions in 2004 and 1998," he said. "If the eruption continues with its current intensity and we get unfavourable winds, we could see ash over the UK. But the past two eruptions in 1998 and 2004 from this volcano did not affect UK air travel," he said.