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Restless Hekla: an update 7 July 2011

Posted by admin in activity reports, Hekla, Iceland.
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Left: Hekla. Right: not Hekla.
The global news machine showed much interest in Hekla yesterday, but little interest in getting the facts right, or indeed the volcano right. Many supposedly reputable news outlets followed AFP’s lead and boldly illustrated their reports on Hekla with a picture of Eldfell, which is many miles to the west on Heimaey Island. AFP even labelled their picture of Eldfell ‘The Hekla volcano on Heimaey Island’, for pity’s sake. You’d think the presence of the sea in the picture of Eldfell would have given it away, Hekla being some distance inland, but apparently not. To help journalists and editors get it right I’ve provided pictures of the two volcanoes above, and obtained the assistance of a passing seven-year-old in providing labels so clear that even Daily Mail journalists will grasp the difference.

There was considerable interest in Hekla yesterday, but media speculation notwithstanding, all is quiet there today and the activity appears to be subsiding. Hekla is closely-monitored and we’ll be as well-informed about what it’s doing as we are about any volcanoes anywhere. In the meantime, it’s best not to jump the gun and read too much into every episode of seismic restlessness.

The forecasting of volcanic eruptions is fraught with uncertainty. Volcanoes, unlike earthquakes, generally give some signal of their intentions in the form of seismic activity, inflation, gas emissions and so on, but working out what those signals mean is no easy matter, and even the most sophisticated analysis of the widest possible range of data can never do more than reduce the level of uncertainty, it can never remove it altogether.

Likewise, a particular volcano’s history is an important guide to current and future behaviour, but no matter how full and detailed our knowledge of a volcano’s past may be, it is not an infallible guide to that same volcano’s future. Significant patterns can emerge from the records we have of a volcano’s previous activity, in terms of eruptive style and periodicity, but they can never be more than indicative. You can’t say, for example, that because volcano ‘A’ turns out to have erupted roughly every ten years since 1970, and it is now 11 years since its last eruption, that a big bang is imminent. Nor can you argue that because the geological record for volcanic field ‘B’ shows eruptive activity about every 2000 years and it is now 5000 years since we last had a peep out of it, it is ‘overdue’ and we should be worried. Human beings like patterns, and we particularly like periodicity: it provides a structure for our understanding of the past, and we like to use it to make some sense of the future too. But it has to be considered alongside other evidence and cannot offer anything but a set of pointers.

For volcanoes a knowledge of the chronological pattern of activity only gets us part of the way to understanding what is going on at any given moment, and what is likely to happen within the next month, year, decade or century — and it can never be definitive. Hekla has a volatile history and is active and restless, and will erupt again, but we do not know when: it could happen tomorrow, or next year, or in ten years or twenty (there was a gap of 23 years between the 1970 eruption and its predecessor in 1947, and 57 years between that eruption and the one before that in 1913, so the ten-year cycle is a pretty recent development anyway). It is not ‘overdue’. Nor is it ‘ready to erupt’:* we’ll know when it is ‘ready to erupt’ because it will then erupt.

* Did Páll Einarsson actually use this phrase? And if he did (in Icelandic), has the meaning he intended been faithfully reproduced (in English translation) by the news sources that have seized upon the phrase? In the past Dr Einarsson has not always been well-served by the way his comments have become distorted in translation or otherwise misrepresented: see examples from October 2009 and February 2011.

Information
Global Volcanism Program: Hekla – summary information for Hekla (1702-07=)

The Volcanism Blog

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Comments

1. Erik K - 7 July 2011

I love that illustration. Love it.

2. admin - 7 July 2011

Thanks Erik. And I *love* your rant: http://bigthink.com/ideas/39186

(Although I wish it wasn’t necessary.)

3. Boris Behncke - 7 July 2011

I love both of your rants, Ralph’s and Erik’s :-D
You’re doing some tremendous work here. Maybe one day the media will note ???

4. admin - 7 July 2011

Thanks Boris. My hopes aren’t high I’m afraid. After all, it’s easier than ever now to check that one’s facts are right (or ought to be) and yet none of these so-called journalists can be bothered, apparently. Here at the blogs our standards are higher!

5. Colin Weaver - 8 July 2011

I love your Hekla / Not Hekla diagram. Pure gold.

Alas it is not just scientific reporting that the media gets wrong. I work in the railway industry in Australia, and can assure you that our local papers get all things railway related just as wrong. I extrapolate this to assume that 99% of what I read in the paper is probably wrong or distorted.

Case #1: according to the media the distance from Brisbane to Cairns, QLD, randomly varies from 1500km to 2000km. The actual rail distance is 1680km, road is similar I guess.

Case #2: a recent article about someone being struck by a freight train at a level crossing west of Brisbane was illustrated with a picture of a suburban train from Adelaide, nearly 1600km away!

And then there is the whole carry on about Dr Joyce apparently saying Western Victoria is overdue for an eruption, as if a monogenetic field can ever be called overdue!

End of mini-rant.


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