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El Hierro - Canary Islands - Possible eruption alert


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http://www.ruv.is/fr...uption-in-katla

Possible eruption in Katla

A glacial flood from volcano Katla, in Mýrdalsjökull, has disrupted highway no.1 (the ring road), by river Múlakvísl on Mýrdalssandur, in the South of Iceland. The road is closed between Höfðabrekka, east of Vík, and river Skálm, near Álftaver. The flood is thought be the result of a small eruption underneath the icecap of Mýrdalsjökull, probably in the Katla crater. The Civil Protection and Emergency Management has sent out a warning to people in the area, to beware of sulphurate smell near the river, as it might be poisonous sulphurate gas. The mountain route Fjallabaksleið nyrðri is open for 4X4 vehicles only, and is the only open road in the area.

The Álftaver area is being evacuated and preparation for evacuating the camping area in Þakgil.

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More detail on the current activity at Katla. Very small event at this point -

http://bigthink.com/ideas/39223

Small jokulhlaup at Katla in Iceland

Erik Klemetti on July 9, 2011, 10:46 AM

For the people of Iceland, the past few years must feel like the old saying "when it rains, it pours': we've seen two significant eruptions, one at Eyjafjallajökull and one at Grimsvötn, in less than a year. Earlier this week, there was news that another Icelandic volcano, Hekla, was showing signs of unrest, although it was unclear whether they pointed towards an eruption. Then, the switcheroo, where instead of anything at Hekla, we get a surprise jokulhlaup (glacial outburst flood) at Katla on the southern end of the island.

Earlier today, Katla produced a small glacial flood (a jokulhlaup) that closed the Ring Road around Iceland. The scientists monitoring the events called it a very small event, possibly only a phreatic explosion under the ice that generated the meltwater.

The jokulhlaup from Katla was fairly small and as of right now there are no clear external signs that the flood was caused by an eruption of volcano. Remember, Katla is covered by a large ice sheet (Myrdalsjökull), so any heating of the glacier from underneath could cause meltwater to build up until it is catastrophically released. There are some circumstantial clues that this could be the result of a very small eruption - first off, Jon Frimann has been tracking the increase in harmonic tremor, an indicator of magma moving in conduits, under Katla. Secondly, there are sightings of cracks in the glacier at Katla (top left), any suggesting a large thermal input under the ice to create weakness in the cap. However, there has been no evidence of eruptive material such as lava or ash, so it is still only conjecture that this flood was caused by an eruption under Myrdaljökull.

With this hiccup at Katla, I'm sure the "disaster mongering" will start to ramp up into a frenzy with people expecting a giant eruption from the volcano. Knowing this, Dr. Freysteinn Sigmundsson even said "At least this is not a large eruption, the Katla eruption people have been waiting for." Katla hasn't erupted since 1918, although there have been events - in 1955 and 1999 - that may have been small eruptive events. When Katla does decide to not hide its eruptive activity, we are likely to expect something fairly large, in the VEI 3-5 scale. However, at this point, this is no indication that Katla is headed towards a major eruption.

If Katla does show signs of a new eruption, there is currently at least one webcam pointed at the volcano - but I'm sure this event will prompt a flurry of new webcams in the near future, so if you find one, post the link here. The Icelandic Met Office also has realtime tremor and GPS information (check out stations GOLA, HVOL and THEY) at Katla, although you have to know where the volcano is located to click on the right station.

In any case, these events at Katla mean we should keep a close eye on the volcano in the coming weeks to months to see if this was another transitory event like the jokulhlaup of 1999 or possibly a sign of things to come. (Oh yes, and I'd like to thank Katla for adding to the cavalcade of volcanoes this year that decide to make noise on the weekend).

The cracking and sagging in the ice cap on Katla after a small jokulhlaup on July 9, 2011 -

myrdalsjokull_sig.jpg?1310222806

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It's never erupted as a 6 (at least not any good evidence that it has, which isn't to say it hasn't). All the documented major eruptions are 3-5, usually a 4, but quite a few 5s in there as well.

With Katla being at such a high latitude and never having erupted as a 6, how did it ever affect the climate?

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With Katla being at such a high latitude and never having erupted as a 6, how did it ever affect the climate?

This is a very good article on Katla's explosive potential. Skivermont is correct. VEI 4 or 5 likely based on past results. VEI 6 is the outside potential of Katla based on its magma chamber size. A 5 would produce a cooler climate. A 6 could cause famine issues.

http://modernsurvivalblog.com/volcano/katla-volcano-10x-100x-eyjafjallajokull/

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This is a very good article on Katla's explosive potential. Skivermont is correct. VEI 4 or 5 likely based on past results. VEI 6 is the outside potential of Katla based on its magma chamber size. A 5 would produce a cooler climate. A 6 could cause famine issues.

http://modernsurviva...jafjallajokull/

Thanks! I'm going to read that now..... this is a fascinating subject :)

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This is a very good article on Katla's explosive potential. Skivermont is correct. VEI 4 or 5 likely based on past results. VEI 6 is the outside potential of Katla based on its magma chamber size. A 5 would produce a cooler climate. A 6 could cause famine issues.

http://modernsurviva...jafjallajokull/

I understand the wiki is not even close to scientific but it does list Katla as possibly having a VEI 6 eruption in 934AD.

the magma chamber beneath Katla is large enough to produce a VEI 6 eruption

To those that say it has never erupted a 6 before I say take caution, we don't know what happened in unrecorded history before, it also does have the potential according to the article you posted.

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I understand the wiki is not even close to scientific but it does list Katla as possibly having a VEI 6 eruption in 934AD.

To those that say it has never erupted a 6 before I say take caution, we don't know what happened in unrecorded history before, it also does have the potential according to the article you posted.

+1

I think many of us forget about this when we look back historically for many different weather phenomena...

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With Katla being at such a high latitude and never having erupted as a 6, how did it ever affect the climate?

A lot of it has to do with sulfur dioxide emissions. The sulfur dioxide emissions are much more important than latitude. A VEI 4 can emit enough sulfur even at high latitude to affect climate (think of Laki). Some eruptions contain much more sulfur than others.

This is a very good article on Katla's explosive potential. Skivermont is correct. VEI 4 or 5 likely based on past results. VEI 6 is the outside potential of Katla based on its magma chamber size. A 5 would produce a cooler climate. A 6 could cause famine issues.

http://modernsurviva...jafjallajokull/

A 5 doesn't necessarily produce a cooler climate.. only if it contains enough sulfur (Helens was a 5 for example with little or no effect).

I understand the wiki is not even close to scientific but it does list Katla as possibly having a VEI 6 eruption in 934AD.

To those that say it has never erupted a 6 before I say take caution, we don't know what happened in unrecorded history before, it also does have the potential according to the article you posted.

Yes I wasn't saying it hasn't done a 6 before, only that none has ever been recorded. Other sources list the 934AD as a 5. But since all the recorded ones are 3-5 I'd say a 4, possibly a low-end 5 is most likely.

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Another small uptick in activity at Katla.

http://www.jonfr.com/volcano/?p=1209

At the moment there appears to be a small earthquake swarm in Katla volcano. Currently this is just a earthquake swarm. All the tremor plots are normal and show no signs of harmonic tremors and magma on the move. The largest earthquake in this earthquake swarm in inside Katla volcano caldera was a ML1.3 with the depth of 1.7 km according to reviewed data from Icelandic Met Office.

There have been about five smaller quakes and a rather decent one (if it verifies) since the latest update above.

110718_0210.png?t=1310955871

110718_0220.png

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So VEI 4 or 5 most likely if it blows completely? Also what if any impact will this have on this winter and the next if we get a big blast? I have yet to hear about that aspect. I have heard something before about latitude being a factor in that as well.

At least 3 ZR events @ KATL

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So VEI 4 or 5 most likely if it blows completely? Also what if any impact will this have on this winter and the next if we get a big blast? I have yet to hear about that aspect. I have heard something before about latitude being a factor in that as well.

The magma chamber is capable of producing a VEI 6, although it is believed that VEI5 is the highest it has produced. If I recall correctly, Katla usually produces VEI4 or low end 5. I believe an equatorial eruption is more influential to the following weather than a high latitude eruption, although the most important aspect may be how much SO2 is involved.

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