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Bárðarbunga update from Icelandic Meteorological Office
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The daily status report for today (25 August) is:
- Intense seismicity continues. Over 700 events have been recorded since midnight.
- Seismicity continues to migrate northward. Seismicity is now concentrated on the 10 km long tip of the dike extending 5 km beyond the edge of the Dyngjujökull glacier.
- At 20:39 last night an earthquake of magnitude ~5 was observed beneath the Bárðarbunga caldera. Since then earthquakes in the caldera have been smaller.
- The dike beneath Dyngjujökull is now thought to be close to 35 km long. Modelling of GPS data indicates that it contains about 300 million cubic meters of magma.
- Additional stations for continuous GPS monitoring will be installed north of Vonarskarð and on Urðarháls within a few days.
- There are no indications that the intensity of the activity declining.
- Currently, three scenarios are considered most likely:
o The migration of magma could stop, attended by a gradual reduction in seismic activity.
o The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dike. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.
o An alternate scenario would be the dike reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
o Other scenarios cannot be excluded. For example, an eruption inside the Bárdarbunga caldera is possible but presently considered to be less likely.
Further we didn't have confirmation of a sub-glacial eruption occurred on saturday morning (23 August) beneath Dyngjujökull glacier. The intense low-frequency seismic signal observed on that date has therefore other explanations.
For any real-time update of the situation please check our web-site: en.vedur.is
Regards,
Sara
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No eruption at Bárðarbunga, Iceland on 23rd of August 2014
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No eruption at Bárðarbunga, Iceland on 23rd of August 2014
To clarify the situation with events on 23rd of August 2014 in Bárðarbunga, people are referred to the notes of the Advisory Science Board of the Civil Protection in Iceland, a panel of scientists from IMO (Iceland Meteorological Office) and IES (Institute of Earth Sciences, University of Iceland) and the joint status reports of IMO and IES, both documents found at e.g. the web page of the IMO:
http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947
http://en.vedur.is/media/jar/Bardarbunga_daily_status_report_en_24082014.pdf
24th August 2014 11:50 - notes from scientists' meeting:
- Earthquake activity in NW-Vatnajökull is still very strong, 700 earthquakes have been observed since midnight and they are somewhat larger than previous days.
- Two large earthquakes, over 5 where in the Bárðarbunga caldera this night.
- The activity under Dyngjujökull has propagated northwards and is now mostly under the edge of the glacier, where an earthquake of size 4,2 was recorded this morning.
- The dike under Dyngjujökull is now estimated to be approximately 30 km long.
- There are no indications that the activity is slowing down, and therefore an eruption can not be excluded.
- Observations show that a sub-glacial eruption did not occur yesterday. The intense low-frequency seismic signal observed yesterday has therefore other explanations.
- The Icelandic Meteorological Office has decided to move the aviation color-code from red to orange.
People are referred to the web-page of the IMO (www.vedur.is) for real-time monitoring while background information and various observations are found on the IES web page (www.earthice.hi.is).
Magnus T. Gudmundsson
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