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Bárðarbunga and Askja - Volcanic Activity


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I am still trying to understand what is happening here but there does seem to be a little confusing information going on. Before I express any thoughts, understand that I am not a volcanologist and th

Did you see the beautiful picture with the eruption glow and northern lights giving surreal lighting effects.   The eruption seen from Jökulsarlón south of Vatnajökull glacier.  (Martin Schultz,

This is my favourite (from elsewhere) to date - very atmospheric.  

Posted Images

 Have been reading an interesting report about the Krafla rifting episode (HOFTON AND FOULGER 1996) and how rifting in one part can have compression effects on other fissures. Over time that compression can reduce and they came up with a little picture to suggest an area where decompression would occur after the krafla rifting episode stopped.

post-2809-0-87733700-1409066774_thumb.jp

Pretty inpressive forecasting in my opinion.

 

One thing I am still confused about is whether the Caldera is collapsing. The nearest GPS I think is HAFS which does not suggest much downward movement at the surface at the moment.

post-2809-0-25573700-1409066914_thumb.pnpost-2809-0-21753400-1409066927_thumb.pn

 

If the magma chamber is being depleted by the infusion into the fissure we should see earthquakes below Bárðarbunga at the depth of the top of the magma chamber. There are no definative answers as to where the magma chamber is. One estimate is as follows (see red arrow)

post-2809-0-06637200-1409067095_thumb.jp

 

That suggests a deep magma chamber feeding into quite a shallow magma chamber. That would suggest the 6km deep earthquakes under Bárðarbunga are actually near the bottom of the magma chamber. (There have been a few smaller ones higher up which might be linked to depressurisation, but I remain to be convinced). Since these earthquakes are on the northern side of Bárðarbunga away from the flow out to the fissure it is difficult to understand what is going on.

 

Rock analysis from vocanoes in iceland comes up with different ideas about how the magma chambers are organised.

post-2809-0-98745900-1409067354_thumb.jp

 

That would appear to be a much more complex system of magma chambers under some volcanoes than others. Bárðarbunga being one of the more complex, and might suggest some linkages bewteen volcanoes.

Some have even suggested that below a certain depth the rock under parts of iceland is a mushy porous rock susceptable to melting.

post-2809-0-77182400-1409067534_thumb.jp

 

If that is the case then I am not sure how it would affect rifting or how deep a fissure would need to be to tap into its own source of magma (Crust is nearly at its deepest under Bárðarbunga at nearly 40km).  What I think I would take from this is that each volcano and rifting area is slightly different and looking for clues from the Krafla eruptions might not be apt.

 

One interesting point is that the fissure seems to have taken a little bit of a left turn from where we might expect it to follow and seems to be following the Askja fissure system.

post-2809-0-75683100-1409068266_thumb.pn

 

So interesting to see happen (at the moment while it has no immediate impact on life), but I still remain confused.  I hope the post is useful and gives a pause for thought, but remember my thoughts are most likely to be wrong.

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The magma may have found some weakness due to the earlier Askjar swarms and moving along those lines of weakness. Next few days will be interesting. Will it hit a block? If it does what then pond or break out at the surface? Or spreadout?

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Latest Info

 

Bárðarbunga - updated information Overview of seismic events in August 2014

In this article, updated information on the Bárðarbunga seismic activity is given with daily status reports from the scientist of IMO and the University of Iceland. New material is added to the top of the article. The original information is at the end of the article. All in all, this article gives an overview of events. For additional material, check also the news list on our front page. Photos from fieldworkare available too.

26th August 2014 15:45 - status report

Overall assessment from the joint daily status report 260814 of the Icelandic Met Office and the University of Iceland, Institute of Earth Sciences:

There are no indications that the intensity of the activity declining. Currently, three scenarios are considered most likely: 1) The migration of magma could stop, attended by a gradual reduction in seismic activity. 2) The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dike. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity. 3) An alternate scenario would be the dike reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity. Other scenarios cannot be excluded. For example, an eruption inside the Bárdarbunga caldera is possible but at present considered to be less likely.

26th August 2014 11:50 - from the Advisory Board of scientists

Scientists from the Icelandic Met Office and the Institute of Earth Sciences, and representatives of the Civil Protection in Iceland, attend the meetings of the Advisory Board.

The following points were the conclusion at a meeting of the Advisory Board today:

  • Intense seismicity continues. Over 500 events have been recorded since midnight.
  • Seismicity continues to migrate northward. Seismicity is now concentrated on the 10 km long tip of the dike extending 5 km beyond the edge of the Dyngjujökull glacier.
  • At 01:26 this morning an earthquake of magnitude 5,7 was observed beneath the
    Bárðarbunga caldera.
  • The dyke beneath Dyngjujökull is now thought to be close to 40 km long. Modelling
    of GPS data indicates that about 50 million cubic meters of magma have added to the volume in the last 24 hours.
  • There are no indications that the intensity of the activity declining. The following three scenarios are still considered most likely:
    • The migration of magma could stop, accompanied by a gradual reduction in seismic activity.
    • The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dyke. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.
    • An alternate scenario would be the dyke reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
  • Other scenarios cannot be excluded. For example, an eruption inside the Bárðarbunga caldera is possible but presently considered to be less likely.

From the Icelandic Met Office:

The Aviation Color Code remains at the "orange" level.

26th August 2014 06:45 - from geoscientist on duty

Seismic activity continues to be high.

Biggest earthquake in the current swarm was measured this night at 01:26. According to USGS the magnitude was 5.7. The event was localized in the northern/northwestern part of Bardarbunga caldera at 6 km depth.

Most of the seismic activity is close to the rim of Dyngjujokull. The dyke is still migrating to the north and the tip of it is already around 10 km outside of the glacier. Most of the events are at the depth of 8-12 km.

There have been no signs of harmonic tremor.

Edited by Lincs Observation
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..........One thing I am still confused about is whether the Caldera is collapsing. The nearest GPS I think is HAFS which does not suggest much downward movement at the surface at the moment....................If the magma chamber is being depleted by the infusion into the fissure we should see earthquakes below Bárðarbunga at the depth of the top of the magma chamber. There are no definative answers as to where the magma chamber is. .........That suggests a deep magma chamber feeding into quite a shallow magma chamber. That would suggest the 6km deep earthquakes under Bárðarbunga are actually near the bottom of the magma chamber. (There have been a few smaller ones higher up which might be linked to depressurisation, but I remain to be convinced). Since these earthquakes are on the northern side of Bárðarbunga away from the flow out to the fissure it is difficult to understand what is going on...........................

 

One interesting point is that the fissure seems to have taken a little bit of a left turn from where we might expect it to follow and seems to be following the Askja fissure system.

http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gifbbbeginman.png

 

So interesting to see happen (at the moment while it has no immediate impact on life), but I still remain confused.  I hope the post is useful and gives a pause for thought, but remember my thoughts are most likely to be wrong.

 

Good post brickfielder.

 

Some thoughts on my part as a layperson

 

Is there a possibility that the magma chamber directly below the caldera is being continually filled from below? 

 

If this is the case, then in the absence of a way out for the new magma, the caldera/volcano would become pressurised and this would be observed as uplift/earthquakes and an eventual caldera eruption.

 

However. There is an outlet - the fissure system extending NE from the SE edge of the caldera.

 

The continual movement of magma into the fissure, prevents any obvious uplift and therefore an eruption of Bárðarbunga itself.  The intrusion into and the extension of this fissure system from the caldera is therefore merely a proxy for this pressurisation.  The large earthquakes on the north part of the caldera rim are also a manifestation of this pressurisation as here there is no local escape route for the magma. This would also explain the lack of gps evidence of any downward movement of the caldera surface.  If this is the case, what happens if the magma moving through the new fissure becomes blocked?

 

Just some thoughts and probably way off the mark but we shall see what unfolds next.

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Good post brickfielder.

 

Some thoughts on my part as a layperson

 

Is there a possibility that the magma chamber directly below the caldera is being continually filled from below? 

 

If this is the case, then in the absence of a way out for the new magma, the caldera/volcano would become pressurised and this would be observed as uplift/earthquakes and an eventual caldera eruption.

 

However. There is an outlet - the fissure system extending NE from the SE edge of the caldera.

 

The continual movement of magma into the fissure, prevents any obvious uplift and therefore an eruption of Bárðarbunga itself.  The intrusion into and the extension of this fissure system from the caldera is therefore merely a proxy for this pressurisation.  The large earthquakes on the north part of the caldera rim are also a manifestation of this pressurisation as here there is no local escape route for the magma. This would also explain the lack of gps evidence of any downward movement of the caldera surface.  If this is the case, what happens if the magma moving through the new fissure becomes blocked?

 

Just some thoughts and probably way off the mark but we shall see what unfolds next.

It's probable that this could happen at some point, but at the moment there is no sign of something called harmonic tremor, which indicates the movement of magma and venting of gases on a detectable scale.

 

http://en.wikipedia.org/wiki/Harmonic_tremor

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From what sense I can make of the general consensus in the Iceland inter-web, the magma or fissure or what ever will/may not reach Askja, it may die or it may create a new Askja(Google Earth) or rather new rather large hole in the ground just like Askja.

A rifting fissure eruption may or may not happen and Bada may still explode like the Tzar Bomb at "her" convenience. Bit like the threat of MAD in the cold war...

 

My guess is yes to all of the above over the next few years. 

 

No need to worry about pension then.

 

Actually it could all just stop for tens of years, if it wanted.

 

Yes it will effect the weather in England and Scotland no matter which way they end up politically... :hi:

 

post-4726-0-43107500-1409082088_thumb.jp

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 If the fissure pressure leak is blocked there could be a pressurized flank eruption of Bada, this would collapse the caldera ice cap would it not. At an angle all at once like Blaster Bates.

 

The fissure blocks backs off flow all the way to Bada, I would imagine a flank breach, in UK English.

 

The lone green star to the West of Bada and now some red dots approaching the Lone green star.

 

 

 

The hot spot that powers up every so often like Hawaii hot spot, it injects pressure and heat melting rock and exuding magma, Iceland with its Ice is more explosive.....

 

Geologically that's it, the pressure will stop when its finished(overriding factor), the side of the volcano will push out and collapse if it has the least resistance. or a new fissure fun will start etc, etc.

 

Expect the lava is going up and down like Hawaii under the glacier, which is like some Brunellian Maidenhead arch, dripping. Because the arch is Ice, with a capitol I

Edited by Rustynailer
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This is the image at Kverkfjoll @20:30

 

http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gifm140825203002575.jpg

 

but i don't know when this snap was taken,i can not see the date/time in the snap :sorry:

 

http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gifkverk1.jpg

 

seems to me that there is some melt  on the lake and slope with some steam vents there.

 

 

http://volcams.malinpebbles.com/pubweb/Iceland.htm

 

i was  reading  what some else said  regarding  

Kverkfjöllum.

  cam   there was snow there yesterday  now its looking  like  steam  not  cloud

You can see how much melt has occurred over the past couple of days compared to that quoted above. The area of the lake showing signs of melt is increasing quickly too, suggesting significant temp rises on the left side.

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3.7M at ASKJA the plot thickens

 

 

Wednesday27.08.2014 01:52:02 65.022 -16.652 3.9 km 3.7 99.0 2.9 km SW of Dreki

 

 

post-18233-0-67331300-1409105888_thumb.ppost-18233-0-20421700-1409105889_thumb.p

 

EDIT : make that 4.5M at askja

 

 

Wednesday 27.08.2014 01:52:02 65.022 -16.652 3.9 km 4.5 99.0 2.9 km SW of Dreki Edited by Buriedundersnow
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Morning All,

 

http://vedur2.mogt.is/kverkfjoll/webcam/images/lon/m140827044002239.jpg

 

Looks like some melting and also some cracking of the surface ice maybe?

 

 

when did the melting in the top right appear I haven't been keeping an eye on the cams at all the last few days?

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3 magnitude 5's overnight and the Kverkjohl cam has multiple jets of steam coming out of the rocks now.

 

http://volcams.malinpebbles.com/pubweb/Iceland.htm

 

 

watch the melting at the top right as well that's where the dyke is I wish the camera was able to turn around so we could see the area where the dyke has progressed to

Edited by Buriedundersnow
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Blimey, take your eyes off it overnight and it goes mad!  Some big events all over the area this morning and now well intersecting Askja.  Yesterday it looked to me like the dyke may track to the east of Askja, clearly its just gone straight for it.  Things could start to get very interesting looking at the discussions presented in the links posted throughout this discussion.  Especially if it reactivates the magma beneath Askja.

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Look at the steam now on this cam @10:20am

 

post-16960-0-10026200-1409135194_thumb.j

 

this was what i posted two days ago

 

post-16960-0-96956400-1409135251_thumb.j

 

there is more melt too,check out the lake,the bottom left ridge and top right along the dyke,there is definately something happening there.

 

http://volcams.malinpebbles.com/pubweb/Iceland.htm

 

also,a lovely clear day should things happen.

Edited by Allseasons-si
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