Official end of eruption declared 28 Feb 2015At noon of the 28th of February, the Scientific Advisory Board for Iceland´s recent volcanic activity officially declared that the eruption at Holuhraun has come to an end.
Eruption continues, but decreases
Update Mon 16 Feb 10:37
The eruption at Holuhraun continues at similar levels as lately, the Icelandic Met Office reports in its updates. The decreasing trend, however, is becoming visible in a significant drop of the lava lake level inside the Baugur crater above the main vents, seen in the photo above.
Photo of the lava lake at Holuhraun on 12 Feb (photo: Ármann Höskuldsson / Univ. Iceland)
"From the field 12 Feb 2015; view from the rim of the southern crater into the lava lake of Baugur. In the foreground, 400m away from the rim, is the southern magma vent. Beyond that there is the northern magma vent, boiling. The lava lake in the foreground is not only glowing; the blackish cover next to the rim indicates some cold crust on its surface, whereas the orange colour reveals liquid magma. Photo: Ármann Höskuldsson. See more photos in a field report from the Institute of Earth Sciences" (Icelandic Met Office).
Update: eruption could go on for many months
Update Tue 03 Feb 07:08
Thickness map of the Holuhraun lava flow field (Scientific Advisory Board)
Caldera subsidence over the past months (Scientific Advisory Board)
Seismic activity under the dyke (IMO) and the Bárðarbunga caldera (blue) (Scientific Advisory Board)
The eruption, now going on for more than 150 days, continues with little changes. Although it has started to decrease, very slowly, in intensity, it remains impressive and magma discharge is still an impressive approx. 100 cubic meters per second.
Graph showing the measured and extrapolated subsidence of the caldera (Scientific Advisory Board)
Caldera subsidence and seismicity continue as well, but a slow decreasing trend of subsidence rate - from initially 50 cm a day to now about half of that now - is visible as well and seems to correlated with the decrease in magma effusion. Icelandic scientists think therefore that subsidence (and hence, the eruption,) might go on for another 5 to 16 months.
The latest report by the Scientific Advisory Board gives a detailed overview, summarized here:
The above prediction, based on extrapolation of measurements and simple models, must be seen with caution:
"It is entirely possible that the eruption will end sooner than predicted above. It is also possible that the eruption could become stable and go on for years, but with a greatly reduced magma flow rate.
An eruption in Bardarbunga is still possible even though the development described above will continue. Even though the volcanic eruption in Holuhraun stops in the coming months it is not certain that the current rifting episode is at an end. It is still possible that an eruption may start on another part of the fissure swarm within the Bardarbunga volcanic system."
"... Three scenarios are considered most likely:
1) The eruption in Holuhraun continues until the subsidence of the Bardarbunga caldera stops. The eruption can still go on for many months.
2) The volcanic fissure may lengthen southwards under Dyngjujokull, resulting in a jokulhlaup and an ash-producing eruption. It is also possible that eruptive fissures could develop in another location under the glacier. If such an eruption would be prolonged it could eventually produce a lava flow.
3) Volcanic eruption in the Bardarbunga caldera. Such an eruption would melt large quantities of ice, leading to a major jokulhlaup, accompanied by ash fall.
Other scenarios cannot be excluded."
Finally, here's an impression from the eruption site in the past days, showing the still large river of lava issuing from the Baugur crater:
Small subglacial eruption ?
Update Fri 30 Jan 11:45
A small earthquake swarm at 1 km below the eastern rim of the Bardarbunga caldera occurred yesterday evening at 21:22 local time, accompanied by a rise in tremor.
Earthquakes at Bardarbunga yesterday (IMO)
Tremor amplitude at DYN station showing the peak during the possible eruption(IMO)
John Friman who closely follows the events in Iceland suspects on his blog that a minor subglacial eruption could have taken place.
If so, a meltwater flood should be expected in the course of the day.