False alarms at Icelandic Volcano
By Doug Newhouse |
The Icelandic Meteorological Office has lowered its aviation warning level from red to orange today, after misinterpreting earlier eruption signs at the Bárðarbunga volcano.
Despite ‘thousands’ of small earthquakes and two very large ones in two days, the IMO has corrected its earlier report of yesterday, stating that its updated data now indicates that the two sub-glacial ‘eruptions’ reported yesterday close to Bárðarbunga were false alarms.
Bárðarbunga is part of Iceland’s largest network of volcanos which are interlinked, although it is not connected to the Eyjafjallajökull volcano which caused so much disruption in 2010 when ash clouds blew over commercial air space, closing many key routes in Europe for more than a week and disrupting more than 10m passenger journeys.
Following yesterday’s false alarm that an eruption was potentially imminent, the Icelandic authorities initially imposed a local no-fly zone around the volcano’s location, although the country’s airports have remained open at all times. The IMO says it is continuing to monitor the situation closely as small earthquakes under and around Bárðarbunga continue with regularity – especially since it is earthquakes that mostly trigger volcanic eruptions.
The big concern that remains with this volcano is that any large eruption will have to take place some 2,000ft down under packed glacial ice. This could lead to a huge release of pressure, so throwing rocks, ice and dust thousands of feet up into the atmosphere, where the journey of any ash cloud would be at the mercy of the winds – as happened in 2010. However, the new protocol for dealing with ash clouds in future now places the responsibility on individual airlines to decide on whether or not they fly if these are present.
Meanwhile, in an earlier statement related to this last weekend’s two large Richter-scale magnitude 5.3 and 5.0 earthquakes, the Icelandic Meteorological Office (IMO) said: “These are the strongest events measured since the onset of the seismic crisis at Bárðarbunga and the strongest since 1996 (the Gjálp eruption). The magnitude is already confirmed by the European EMSC network and the GEOFON network of GFZ Potsdam in Germany.
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“Probably, earthquakes near the Bárðarbunga caldera are a consequence of adjustment to changes in pressure because of the flow of magma from under the caldera into the dyke, which stretches to Dyngjujökull, more than 25 kilometres away.”
Commenting on events, EUROCONTROL said: “At this time, there has not been an ash eruption and there is no impact on aviation. EUROCONTROL, as Network Manager, is monitoring the situation closely and will publish any updates on it Network Operations Portal. An ad-hoc meeting of the European Aviation Crisis Coordination Cell was held on the morning of 24 August to review the situation.”
[See earlier story on this latest volcanic incident: http://www.trbusiness.com/index.php/regional/europe/15801-iceland-heightens-volcano-alert.html].
IMAGE ABOVE: The top image shows the Eyjafjallajokull volcanic ash cloud which caused European air space chaos for more than a week in 2010.
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