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Eyjafjallajökull and Katla: restless neighbours 4 March 2010

Posted by admin in activity reports, Eyjafjöll, Iceland.
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The Icelandic volcano Eyjafjallajökull has been very restless recently. The current seismicity and apparent inflation may be precursory to an eruption, or it may not – as Hugh Tuffen of Lancaster University observes, this kind of activity has been seen before, associated with dyke intrusion events (although the current seismicity is unusually energetic) and it is not possible at the moment to say whether this time it will end in an eruption: ‘time will tell’. An interesting detail about the current activity comes from a source in Iceland who tells me that magma degassing under Eyjafjallajökull produced an ‘acid pulse’ that led to local water supplies become temporarily acidic about a month ago.

Eyjafjallajökull is an interesting volcano, not least because of its relationship with its near neighbour, Katla. This much larger volcano lies less than 30 km to the east of Eyjafjallajökull, beneath the Myrdalsjökull icecap. Katla is, the Global Volcanism Program reports, ‘one of Iceland’s most active [volcanoes] and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods’. Katla, with more than twenty confirmed eruptions since the sixth century AD, has a much more active eruptive history than Eyjafjallajökull, which has just three eruptions over the same period. It seems, however, that there is a connection between these two closely-spaced volcanoes. Eyjafjallajökull’s most recent eruption, December 1821 to January 1823, was followed by an eruption of Katla in June and July 1823. More recently an intrusion at Eyjafjallajökull in 1999 appears to have been followed by a small subglacial eruption in the Katla caldera.

It’s intriguing that recent earthquake activity around Katla and Eyjafjallajökull has clustered in three areas: (1) shallow quakes around and within the Eyjafjallajökull caldera, (2) shallow quakes largely confined to the eastern part of Katla caldera, and (3) quakes with a deeper focus in the Godabunga area between the first two clusters. One possible interpretation of this pattern is that a cryptodome – an underground lava dome – is active beneath this area. The presence of viscous rhyolitic lava beneath Katla and Eyjafjallajökull makes for potentially explosive eruptive activity, if an eruption occurs.

An Icelandic commenter at Eruptions reports that the Iceland Meteorological Office do not expect an eruption at Eyjafjallajökull. The volcano may get over its current bout of restlessness and calm down again, as happened with the intrusion events of 1994, 1999 and 2009. It clearly needs careful watching, however, as does its large and destructive neighbour, Katla.

[Grateful thanks for information received to 'a source at the Department of Geophysics, University Of Iceland'.]

The Volcanism Blog

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1. Chance Metz - 4 March 2010

Something looks fishy here. It would eb swwet to see a volcanic eruption in progress.

2. Pamela Ross - 5 March 2010

I’ve been noticing the activity on the Icelandic website which shows recent earthquake activity – lots of red dots!

3. James - 5 March 2010

I have it on good authority that scientists from University of Iceland will be meeting with officials from the Civil Defence Authority (or whatever the Icelandic equivalent is called) today, specifically to discuss Eyjafjallajokull. I’m not sure if the Icelandic Meteorological Office are also involved, but it’s probably likely.

It certainly seems that the government are now beginning to take this quite seriously.

It is also important to note that since the volcano in question hasn’t erupted since 1823, no-one is really sure what to expect here. If an eruption occurs, it could be a mildly explosive but predominantly effusive eruption (similar to the Hekla eruption of 2000, for example, where an early sub-plinian phase gives way to fire-fountaining), or given the fact that it’s a central volcano with more evolved magmas, there is always the possibility that the eruption could be more explosive, involving rhyolite magmas. Of course, likely being sub-glacial, water-magma interaction would probably be in effect too. Certainly it’s somthing of an open book, and so a lot of caution will be exercised early on should an eruption occur until it is determined what exactly is going on.

Added to the distinct possibility of a jokulhlaup occuring, Eyjafjallajokull isn’t a volcano to be taken lightly, and it will be interesting to see how this pans out.

4. Chance Metz - 5 March 2010

sounds like even the govermnet there thinks sometihng big might happen.

5. icelander - 21 March 2010

we have an eruption now. like in just now :)

6. Garth Attaway - 21 March 2010

Now that there is an eruption in progress would love to see seismic readings from Katla caldera.

7. Blossi - 23 March 2010

and the eruption is still going on and the pressure is still growing under
the glacier ….witch means ….ups !! something will have to give away .

easy does it , I live not far from it .. no worry at all , I fled
the VestmannIslands 1973 , what we have to have in mind
is Katla .

hot Icelander :O)

8. tony malone - 26 March 2010

Why haven’t we heard any updates concerning Katla?

9. admin - 26 March 2010

Thus far, all seems quiet at Katla. If anyone out there has solid information to contribute concerning activity at Katla, please get in touch or leave a comment.

10. keith stone - 16 April 2010

I’ll bet this article will get some reads after this one! Best wishes to those that live there.

11. LJ - 16 April 2010

Yep it did, I was wondering about Katla too.

12. Jon Abraham - 17 April 2010

Is it a good idea to stockpile clean water in the uk…..? ….just in case katla blows…?

13. My name is Unknown - 18 April 2010

Wow, that Volcano has caused soo much trouble across Europe…

14. John Plimmer - 18 April 2010

Katla is well overdue…. Will probably blow before the autumn.
P.S. Do we have any clean water in the UK now?

15. A.Waterston - 19 April 2010

Past Events would suggest Katla activity within 6-9 months

16. Godabunga - 20 April 2010

Interested to read interpretation of the activity being measured by the Godabunga sensor. It looks rather ominous.

17. M. Wessel - 22 April 2010

all six seismic recordings showing increased activity in since noon April 21 UTC
Can’t find any commentary of this yet.

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