Seismic activity in Bárðarbunga volcano under Vatnajökull glacier continues to be strong, but has somewhat decreased, as reported by the Scientific Advisory Board of the Icelandic Civil Protection yesterday. The lava flow is still great in Holuhraun and the rate of the subsidence of the Bárðarbunga caldera is still significant.
The total number of earthquakes in Bárðarbunga from the board’s last meeting on December 30 was just over 250 of which about 20 were between magnitude 4.0 and 5.0. The strongest in the period was a magnitude 4.9 earthquake, which hit at 9:53 pm on December 5.
About 50 earthquakes were detected in the intrusive dike, connecting Bárðarbunga with the Holuhraun eruption site, in the same period, most of them smaller than magnitude 1.0.
Seven earthquakes were detected in Tungnafellsjökull glacier in the period. The strongest was around magnitude 3.0 and occurred on December 30.
Geophysicist Páll Einarsson stated recently that the activity in Bárðarbunga may trigger an eruption in the volcano which lies under Tungnafellsjökull, as indicated by the increased seismicity in the glacier.
The Scientific Advisory Board reports insubstantial changes to the volcanic eruption in Holuhraun over the last few weeks. The lava is now both flowing inside closed channels and on the surface of the lava field.
Data collected in a flight over the lava field on December 30 shows that the volume of the lava which has erupted in Holuhraun measures approximately 1.15 cubic kilometer (0.28 cubic mile).
GPS measurements of the northern Vatnajökull glacier shows continued slow deflation towards Bárðarbunga. The rate of the deflation continues to slow down.
The GPS station in Bárðarbunga caldera shows that the caldera continues to subside. The rate of the subsidence continues to slow down and is now around 13 cm (5 inches) per day.
The volcanic eruption has now been going on for over three months. The Scientific Advisory Board concludes that the lava flow is still great in Holuhraun and the rate of the subsidence of the Bárðarbunga caldera is still significant.
Future scenarios include a sub-glacial eruption in Bárðarbunga, accompanied by ashfall and jökulhlaup glacial outburst floods, although the eruption may also gradually slow down until the subsidence of the caldera stops.
However, the eruption could go on for months, the report points out, and Páll believes Bárðarbunga may impact other volcanoes in the vicinity, including Tungnafellsjökull.