This is just a short overview of the Askja volcano earthquakes that have been taking place over the past few weeks. I do not at this have a good picture of what is happening in Askja volcano.
In Week 15 earthquake activity started north of Askja volcano. This activity have been growing since then, with considerable difference between Week 16 and Week 17. Currently the earthquake activity is ongoing. It is not clear if this earthquake activity has slowed down or not. Many of the earthquakes that are taking place north of Askja volcano are shallow. But most of the earthquakes are happening on a depth from 1 km and up to 0.0 km. I am currently unclear on why the activity is so shallows as seems to be the case.
A second set of earthquakes have also been taking place in Askja volcano system. But this earthquakes are taking place east of main Askja volcano. But Askja volcano fissure system goes east and then north from the main volcano. It also goes several km south of main Askja volcano. But that area has not seen any activity so far. While the activity east of Askja volcano is not clustered as it is north of it. It is showing many of the same signs as the earthquakes north of Askja volcano. They are shallows with most of the earthquakes taking place in less then 1 km depth. As before I am not sure why the earthquakes are taking place on less then 1 km depth. But one idea for both the earthquakes north and east of Askja volcano is that there is magma pushing up the bedrock north and east of Askja volcano. But does not at this time have the power to break up trough the crust and start a eruption. Only one deep earthquake has so far been recored, it was on a 22,8 km depth. The location of this earthquake was not far from Herðubreiðartöglum mountains.
Due to lack of GPS data it is hard to see any deflation or deformation in Askja volcano. But it has been known since last year (2010) that Askja volcano has started to prepare for a eruption. But it remains unclear how long it is until Askja volcano is fully ready for a eruption. Last eruptions that took place in Askja volcano where in the years 1961, 1938, 1926, 1924, 1923. More on Askja volcano eruption history here (GVP web page).
A bit OT here but how come Holmsa station east of myrdalsjökull is showing such a strange pattern in water flow?
http://vmkerfi.vedur.is/vatn/VV_Frame.php?r=15556&load_graph=1&direct=1&station_id=218&station_name=Su%F0urland&page_id=270
The link is a one year chart and it seemed pretty calm last year around this time.
This is normal, the winter snow has started to melt in Iceland.
Broken link, also the main link asks for a user name password?
Go to http://www.vedur.is to see the station graphics there.
Thanks for the link, jon. Reading your post, seems allot has happen in the past year or so for Askja, Do you know of any reports any small cracks or lake temp change in the last few weeks?
I found this on my travels, Its not dated. I think it might be basic stuff for you and some others, for me not so much. 🙂
http://www.geokem.com/OIB-volcanic-iceland.html
Besides increased earthquake activity. I have not got any other reports of changes in Askja volcano.
We recorded a maximum temperature today of 20.5ºC north of Selfoss.
It is an astonishing warm temperature for this time of the year in Iceland.
And as the night falls, there are places on the east still with 14ºC. How crazy this is.
I imagine the strangeness today in Reykjavik with a beautiful day with a maximum of 16ºC and 10cm of melting snow on the streets! When it snowed in Reykjavik 2 days ago, here was raining with a temperature of 9ºC, and we are just 1 hour east.
The snow was mostly gone in the morning, in the afternoon nothing was left of it. The Hengill mountains are an excellent barrier for the weather, which is often the complete opposite on both sides.
Actually, early this morning (late night in Rio) I saw it snowing in Mila’s Reykjavik lake cam.
Heavy snow: streets, church and swans blanketed in white! 🙂
Last year when I was in Iceland in the beginning of May it was also this warm..
We had 19C near kirkjurbaerklaustur (or something like that :P)
It is getting clear. Earthquake activity in Askja volcano is increasing and it appears to be speeding up far as I can tell.
Jon, care to venture any ideas at this point on how this likely would play out if it were close to an eruption? Are we going to see hundreds of quakes?
Or is it too soon to speculate?
I think Askja volcano behaves in some part like Krafla volcano before a eruption starts. That is a lot of small earthquakes and some earthquakes even going up to Mb5.0 or larger.
But that is just a guess. What is going to happen is a bit unclear due to the fact that last eruption was in the year 1961.
What also strikes me is the small magnitude of the earthquakes. When the earthquake swarm in Krysuvik happened there were a lot of M2+ earthquakes.
Is there a reason for this?
I guess it is due to Askja being situated at the spreading zone. Rock is already pretty much fractured, and thus needs very little new fracturing for lava to rise up.
More informative links re: Askja. Important to note that the 1875 fissure event was a VEI5 and was Phreatic (http://www.volcano.si.edu/world/volcano.cfm?vnum=1703-06=&volpage=erupt)
http://www.springerlink.com/content/wk7h583281766611/
http://www3.hi.is/~heidi/Data/Herdu-Askja-literature/SturkellSigmundsson00.pdf
Much like Eyjafjallajökull, there were different magma compositions involved in the 1875 eruption; a basaltic fissure eruption was followed in short order by a Plinian eruption of rhyolitic magma, and caldera formation.
The phreatic component was relatively minor, resulting in the creation of the Viti crater towards the end of the eruption.
Mike
Largest earthquake so far ML2.5 at the depth of 0.1 km. It had low period earthquake signature if I read the IMO data correctly.
Seems like we have to change bets about which volcano erupts first!
Though I guess there is still a good chance that nothing will happen :P!
Sander
This is getting really interesting what is happening in Askja volcano. When it might erupt is a good question.
But with ML2.5 earthquake at 0.1 km depth. It can’t be that long until a eruption happens.
Off-topic: It has happened again with me. I have finished paying all the bills and no money left for food. 🙁
In fact, it is so bad now that I can’t even pay all the bills now since I am out of money.
Any help in this matter with a donation appreciated . Thanks for the support!
I recommend that people use Google Earth or a like to view Askja volcano system from space.
Lol I just watched Askja on google earth and now you post it to do so ..
Pretty impressive volcano! wonder what will happen and where…
Sander
I wonder if an eruption at Askja would accellerate an eruption at Bardarbunga given they share the same system.
Things are heating up. I am just wondering what the time frame here is. 1-2 days, 1-2 weeks
Activity is clearly growing in North part of Askja volcano. The deepest earthquake so far was today on 19,6 km depth.
So far the main activity is in the north part of Askja volcano.
This at Svartarkot looks to me similar to what happened recently at grimsvotn.
http://hraun.vedur.is/ja/oroi/sva.gif
Some of the more recent quakes have been midway between here and askja, is this of any significance?? What is happening here at Svartarkot??
This are mostly earthquakes from Askja volcano. But nothing else is going on far as I know.