Iceland - Iceless crater lake of the volcano Askja causes speculation

[Pathfinder]

04.04.2012 | 16:45

Photos: Iceless Iceland Volcano Lake Causes Speculation

http://www.vatnajokulsthjodgardur.is/starfsemi/a-dofinni/nr/604

There is currently no ice on ?skjuvatn, the crater lake of the volcano Askja in the northeastern highlands, which is unusual for this time of year. There are two possible reasons: increased geothermal activity or a snow-light winter; scientists lean towards the first option.
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?There is something unusual going on, either a weather-related phenomenon or there is increased geothermal heat in the lake,? Bj?rn stated.
The Coast Guard?s airplane with which he flew, TF-SIF, is equipped with heat cameras and they were used in the search for increased flow of heat.

?We didn?t see anything on the surface and it didn?t seem as if there was increased geothermal heat around the lake,? he said.

?So there are two possible reasons for [the lake?s iceless state]: increased flow of heat from the geothermal area below the lake or a winter with little snow and strong southwesterly winds,? Bj?rn reasoned.

However, as he pointed out, Lake M?vatn, which lies lower than ?skjuvatn but in a similar area, currently has an ice cover. Therefore, geothermal heat is the more likely explanation, he concluded. Further research is necessary to confirm his suspicion.
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Full text:
http://www.icelandreview.com/icelan...no_Lake_Causes_Speculation_0_388867.news.aspx

 

[Pathfinder]

Re: Iceland - Iceless crater lake of the volcano Askja causes speculation

Unexplained Melting at the Askja Crater Lake in Iceland

By Erik Klemetti
April 6, 2012 |
8:02 am |


The crater lake at Askja in Iceland. The lake is normally covered in ice during this time of the spring. The "ash" marked on the image is unconfirmed and could be dust or material from fumaroles. Image courtesy of the NASA Earth Observatory and processed by Robert Simmon.

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The most recent activity at Askja was in 1961 that produced lava flows near ?skjuvatn ? a pattern of eruption that was seen in numerous times since the VEI 5 eruption in 1875. That caldera-forming eruption in 1875 was large enough that ash and tephra fell as far away as Norway and Sweden. Much like the 2010 Eyjafjallaj?kull eruption, the explosivity of the eruption was likely aided by the meltwater that is readily available at Askja. If you go back to the rhyolite eruption in ~8910 B.C., that ash from that caldera-forming event is found over much of Europe.

After hearing about the melting ice on Askja, I asked Robert Simmon from the NASA Earth Observatory is they had any imagery of the Askja are to see if I could see the melting for myself. Well, as you might guess, trying to image the middle of Iceland in winter from space is, ahem, problematic. However, Robert did find three image that show the lake becoming more-and-more ice-free between February 23 and March 23. The most recent image is at the top and shows ?skjuvatn nearly ice-free. It also shows V?ti on the top right of ?skjuvatn and a coating of something on the snow surrounding V?ti. {SPECULATION ALERT} Now, it is marked as ash on the image, but there is no confirmation. However, it is hard to come up with any other explanation ? some idea might be windblown dust from inside the small warm crater lake or staining from fumaroles that can occur inside V?ti. If it were ash, it could be from steam explosions inside V?ti that blasted little material out as the water got hot enough to form steam. This discoloration is not visible on the March 6 image (see below), so something new has happened {SPECULATION END}.
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Full text:
http://www.wired.com/wiredscience/2012/04/unexplained-melting-at-the-asjka-crater-lake-in-iceland/

 

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Re: Iceland - Iceless crater lake of the volcano Askja causes speculation

J?n Fr?mann also has some interesting pictures and additional information on his blog:

http://www.jonfr.com/volcano/