Tuesday, March 20, 2012

Katla Volcano Has Another Quake Swarm

Katla volcano in Iceland is having another quake swarm today, during what some say is supposed to be a quiet time geologically for Iceland, during the harsh Winter months. Seismicity is elevated today at the Mýrdalsjökull glacier, with some quakes even occurring at the neighboring Eyjafjallajökull volcano. Eleven tremblors struck within the Katla caldera within the last 24 hours. As I write this, the swarm is ongoing. Most of the quakes except for two were below 2.0 in magnitude, with the largest being a 2.5. Many smaller >1.0 quakes occurred.

This again is probable dike intrusion into Katla, which has seen elevated seismicity and geothermal activity since its very small eruptive event last year (which produced a glacier outburst flood, and caused minor damage to bridges and roads). 

Image from Iceland Met Office showing today's quakes at Katla/Mýrdalsjökull 

Katla has been seismically active for months, with most scientists expecting an eruption soon.When is impossible to say, however this will likely be larger than last time due to the amount of magma intruded into the system. Swarms have occurred at the volcano at least a few times in any given month since June of 2011, but so far has not resulted in a large eruptive event like its neighbor Eyjafjallajökull, who's eruption in April 2010 produced a large ash cloud, carried by the jet stream, and stranded millions of travelers in Europe as airliners were grounded due to ash concerns.

Europeans fear a repeat of this event should Katla erupt, however it is anyone's guess whether an ash cloud from Katla would even follow the same pattern. It is entirely possible that the ash cloud going go East, and give the United States East Coast a taste of the headaches that Europeans suffered. Or the ash could simply blow South, into the ocean, harming no one. In any case, Katla rumbles on, gearing up for its inevitable show. 


  1. Thank you! as I understand it, Kata has a much more coarse ash than Eyjafjallajökull so it should not cause similar problems with air traffic. Eyjafjallajökull's ash is very fine, like talcum powder. Kata's is not.

  2. It's definitely hard to say given that Katla's last eruption was so long ago, and we only have tephra layers to look at from long ago. Some volcanoes do get injected with different types of magma on occasion. Mt. Hood in the US has seen three to four different types of lavas erupt from it, sometimes occasionally mixing to create extra-explosive eruptions! While I don't think this would happen at Katla, being a "hotspot volcano of Iceland", it's always a possibility. The hard thing about volcanology is that a lot of times, volcanoes can make enthusiasts and scientists alike look very stupid, especially when they erupt in a completely different way than predicted... just look at El Hierro! The government has "declared" the eruption is over, but the R.O.V. mission the other day proved otherwise, with actual video of pillow lavas being extruded!


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