Iceland's largest volcano is preparing to erupt and could blast a huge ash cloud across Europe, experts have warned.
The 6,590ft Bardarbunga volcano, buried under the Vatnajokull glacier, has been struck by four earthquakes in the past week, with the strongest one measuring 4.7 on the Richter scale.
Seismology expert Páll Einarsson said the quakes showed Bardarbunga is "clearly preparing for its next eruption." He told the Daily Star that the tremors were part of a series that has been "in progress for two years".
"The reason for the earthquakes in this place is that the volcano Bardarbunga is inflating, i.e. the pressure of magma in the magma chamber is increasing. It has been doing this since the last eruption ended, in February 2015," he said.
Earth scientist Dr Simon Day of University College London said that earthquakes could "precede a large explosive eruption and consequent widespread ash fall".
The last time the volcano blew was in 2014, triggering the largest eruption in Europe in over 240 years. Although the volcanic fumes did not disrupt flights, emissions did impact the air quality in Iceland.
When another Icelandic volcano erupted seven years ago and veiled Europe in a cloud of ash, it triggered travel chaos across Europe, leading to almost 100,000 flight cancellations and delays.
Dr Thomas Walter, from the GFZ German Research Centre for Geosciences, told The Daily Mirror that a Bardarbunga eruption could be a lot worse as the volcano is located underneath ice.
"In that case, we'd have had a water vapour explosion with a volcanic ash cloud even bigger and longer lasting than the one that followed the eruption of Eyjafjallajokull in 2010," he said.
The Icelandic Meteorology Office has not issued any warnings, but activity levels for the Bardarbunga volcano are described as "high".