A 5.3 magnitude earthquake occurred Sunday morning near the Bardarbunga caldera, the strongest ever measured since the onset of the seismic crisis at Bardarbunga volcano, according to the Icelandic Meteorological Office (IMO).
The IMO said the 5.3 magnitude earthquake at 5 km depth was measured at Bardarbunga caldera at 0009 GMT on Sunday. Its origin was at the northern rim of the caldera.
Another large earthquake of magnitude about 5, originated at the southern rim of the Bardarbunga caldera rim, occurred at 0533 GMT.
The IMO said, earthquakes near the Bardarbunga caldera were a consequence of adjustment to changes in pressure because of the flow of magma from under the caldera into the dyke which stretched to Dyngjujokull, more than 25 km away. But no signs of tremor or indicative of eruption were detected during the night.
Since a small sub-glacial lava-eruption was detected under the Dyngjujokull on Saturday, the IMO raised the aviation color code from orange to red. A 140 by 100 nautical miles no fly-zone was ordered over the eruption site.
The Icelandair, the biggest airline company in Iceland, said in a statement on Sunday, there was no flight disruption at this stage. They were closely monitoring the situation and would advise of any schedule changes if necessary.
Bardarbunga volcano, located under the 800-meter-thick Vatnajokull glacier, is Iceland's second highest mountain at 2,000 meters above sea level and also one of the most dangerous volcanoes.
Since the onset of the earthquake swarm at Bardarbunga on last Saturday morning, thousands of earthquakes have been detected around that area.