“Intense seismic activity” began at the volcano on 16 August, and there was a strong earthquake in the region early on Monday, the met office said.
“This is the strongest earthquake measured in the region since 1996.
“Presently there are no signs of eruption, but it cannot be excluded that the current activity will result in an explosive subglacial eruption, leading to an outburst flood and ash emission,” the met office said, adding that the situation was being monitored.
The risk level to the aviation industry has been raised to orange, the second-highest level, the met office said.
Update 23rd August : Volcano alert level raised to red
*** Update 24th August: Alert level reduced to orange. ***
Update 29 August** Warning A fissure eruption has started north of Dynjujökull.** (Richard Holle)