Saturday, February 4, 2012

Tremors at Eyjafjallajökull and Katla (Iceland) Today

Several small quakes struck Eyjafjallajökull today, as the seismic swarm continued at Katla caldera in Iceland. Two small flank tremors and one at the summit hit Eyjafjallajökull within the last 12 hours. Numerous other small tremors have also continued under the Mýrdalsjökull glacier capping Katla's caldera system. Several volcano moitoring scientists, agencies, and bloggers have noted the unrest under Katla, and suspect that minor dike intrusion is occurring under the volcano.

The quakes and tremors under Eyjafjallajökull are small, but four have occurred within the last 12 hours. Numerous tremors can be seen under Katla. None of these quakes exceed magnitude 3.0.

In the case of Eyjafjallajökull, it is entirely possible these are not volcanic quakes, rather they could be structural adjustments to the volcano due to it having had a recent eruption (April 2010), and further settling of the volcano on the crust. GPS deformation charts are not available to look at at this time, so it is unclear if inflation or deflation is occurring. Looking at the Iceland Met Office website, all GPS data looks flat on all sites, so their equipment may not be functional at this time (I blame the weather). It will be interesting to keep an eye on, nonetheless.

Eyjafjallajökull caused havoc for air travel to and from Europe during its eruption that began in April of 2010. It was a fascinating eruption to watch, as it started out with a somewhat benign and beautiful fissure eruption on its NE flank (in an area known as Fimmvörðuháls) between the main summits of Eyjafjallajökull and Katla. This eruption lasted around a month, and became quite a tourist attraction, with a great webcam view for a time. After the cone ceased to erupt, there was a short lull in activity from the volcano, before it erupted suddenly and powerfully from its main summit caldera. The eruption was actually rather minor for an Iceland volcano, but due to prevailing winds, and the latitude of the eruption, Europe and Europe's airspace was choked with ash.

This resulted in a months long ban from air travel, while Europe and other parts of the world bemoaned Eyjafjallajökull and the severe inconvenience it brought upon them. Celebrities were stranded, industries were paralyzed, and in the end, Eyjafjallajökull caused billions of dollars to be lost due to economic damage.

Iceland volcanoes have a violent history. Some of its eruptions have been devastating on a global scale, especially the famed Laki fissure eruption that covered a large part of Iceland in volcanic basalt lava, and unleashed incredible amounts of sulphur dioxide into Earth atmosphere for years. This caused a worldwide famine, global cool down, and some say it was actually responsible for sparking the French Revolution! And eruptions from Hekla are famed for the terror they caused to ancient Vikings, who referred to it as "The doorway to Hell".

This has made any news about Iceland volcanoes hot topics for tabloid news, and the usual rabble like Fox or the BBC/Daily Mail. Eyjafjallajökull is NOT currently erupting, nor is it expected to again any time soon. However, volcanoes do have a habit of reminding us that they cannot be predicted in the first place, so vigilance is important with volcanoes, especially the ones that have erupted in historical time. So to be clear, there are NO eruptions currently going on in Iceland, and nothing is imminent. It looks like Katla might be reloading, as well as Grímsvötn (American name). But neither has erupted yet this year.



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