Volcano Blog by Tom Pering
  • Blog
  • UV Cameras
  • Publications
  • Slug Calculator
  • About Me

Katla, the volcano that everyone is waiting to blow.

13/12/2011

 
Katla lies beneath the Mýrdalsjökull ice cap and has height of approximately 1512 m. Katla has been showing increasing signs of unrest for many months now with periods of harmonic tremor prompting news reports of an impending eruption. Also, historically, an eruption of the Eyjafjallajökull volcano is often followed by one at Katla.

However some of these news reports are citing the global impact an eruption may have. As a result I have a couple of comments about a recent BBC article titled New Icelandic Eruption Could Have Global Impact. First of all due to the high latitude of the volcano,a 'global impact' is unlikely, the majority of eruptions which transport ash globally and affect global temperatures are closer to the equator and if you look at past eruptions of Katla, the largest they reach is VEI 4/5 which is large, but not on the scale which Tambora or Pinatubo were. It is possible that ash will be transported through Europe again, although there are a number of factors which affect the transportation of ash other than wind direction, including ash particle size and strength of the eruption so even this isn't certain!

One of my main gripes, it is very unscientific and bad practice to say a volcano is overdue! Its seen with Yellowstone all the time, its not acceptable there so it isnt for Katla either! 
Katla
Steam rising over the Mýrdalsjökull ice cap.

One of the major hazards from volcanoes such as Katla which lies beneath the  Mýrdalsjökull ice cap  is the jökulhlaup. These occur when an ice cap/glacier is heated from below, these events are usually triggered by a sub-glacial volcanic event.  Such an event occurred on the 9th July from the Mýrdalsjökull ice cap and was likely trigger by an increase of heat flux from the caldera or a small sub-glacial eruption, this is a further indication of activity beneath the surface of Katla. There was also an episode of this kind in 1999. 

I confess that I am not the first one to write about this, but I felt the point needed to be made that caution should be taken when reading articles making claims such as the BBC article.

So to summarise, Katla is showing signs of an eruption, with periods of harmonic tremor indicating the possible movement of magma beneath the caldera, however Katla will go when she wants to go!

Share this page
Morgan
14/12/2011 12:26:24 am

Hi Tom

Thanks for the interesting read. Just a couple of comments and clarifications.

While it is more difficult for a high latitude volcano to have a global impact, it is not impossible. Any ash or sulphate that reaches the stratosphere affects the dispersal of radiation and therefore the heating, which then changes the jet streams in the vicinity. For Katla, that would mean the North Atlantic Oscillation (NAO), which is linked (in a very complicated way) to the El Nino Southern Oscillation (ENSO) in the Pacific. Therefore, if the eruption is of sufficient magnitude, the climatic effects can cause disturbances that become global (even though the dispersal of ash does not).

I completely agree that it is bad practice to say volcanoes are overdue. It is also unfortunate (but not surprising) that the world's media look at Katla and go straight for the worst case scenario, when it could erupt on a scale similar or smaller than Eyjafjallajökull.

One final thing, there is still some contention about the Jökulhlaup in July. While the tremor looked like a small eruption, geochemical measurements of the water coming out of the glacier showed no signs of being melted by lava (it had a high alkalinity which suggests a long time interacting with a geothermal system). So while it could have been a small eruption, the evidence isn't conclusive.

Thanks again for the blog
All the best :)

Polo Ralph Lauren link
29/1/2012 12:42:12 am

Very nice! Really beautiful!

Chemistry link
12/4/2012 12:01:00 pm

Just gorgeous !


Comments are closed.
    Volcano Blog Logo

    RSS Feed

    Share this page

    Archives

    August 2022
    May 2022
    January 2021
    February 2020
    December 2019
    November 2019
    April 2019
    January 2019
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    October 2017
    August 2017
    June 2017
    January 2017
    October 2016
    July 2016
    June 2016
    May 2016
    April 2016
    January 2016
    December 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    January 2015
    December 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    January 2014
    November 2013
    October 2013
    September 2013
    August 2013
    July 2013
    June 2013
    May 2013
    April 2013
    March 2013
    February 2013
    January 2013
    December 2012
    November 2012
    October 2012
    September 2012
    August 2012
    July 2012
    May 2012
    April 2012
    March 2012
    February 2012
    December 2011
    November 2011
    October 2011
    September 2011
    July 2011
    June 2011
    May 2011
    April 2011
    March 2011

An informative blog for anyone interested about all things volcano related!
  • Blog
  • UV Cameras
  • Publications
  • Slug Calculator
  • About Me