iceland Bárðarbunga and Askja - Volcanic Activity

[Pixel]

http://davemcgarvie.wordpress.com/2014/09/07/so-what-if-there-was-an-eruption-at-the-bardarbunga-caldera/

 

Hope this hasn't already been posted.. just found a very good read  - not very long but understandable

[karyo]

Where are you seeing that? - he is quoted as saying "This is just the beginning"

 

 

http://www.mbl.is/frettir/english/2014/09/17/this_is_only_the_beginning/

 

PS. A piece on the Reyk­janes mud geysers.

 

http://www.mbl.is/frettir/english/2014/09/17/mud_geysers_heating_up_in_iceland/

It is a comment in the Jon Frimman site: http://www.jonfr.com/volcano/?p=4988&cpage=3#comment-60052

 

Check comment made at 11:39am which says: The seismic activity of the Bárðarbunga am losing more and more, the volcanologist Ãrmann Höskuldsson said yesterday in a press conference. I emphasize: YESTERDAY! This morning, or at night, there were already two in the Bárðarbunga quake of 5.4 and 5.2 mag.

The scenario for the coming weeks, outlining the volcanologist is quite optimistic:

The volcanic activity diminishes, perhaps still opens one or the other craterlets and more Rifte poppen on how far in Holurhaun. The risk of a major outbreak has dropped enormously, Höskuldsson says in Morgunbladid.

[Gael_Force]

It is a comment in the Jon Frimman site: http://www.jonfr.com/volcano/?p=4988&cpage=3#comment-60052

 

Check comment made at 11:39am which says: The seismic activity of the Bárðarbunga am losing more and more, the volcanologist Ãrmann Höskuldsson said yesterday in a press conference. I emphasize: YESTERDAY! This morning, or at night, there were already two in the Bárðarbunga quake of 5.4 and 5.2 mag.

The scenario for the coming weeks, outlining the volcanologist is quite optimistic:

The volcanic activity diminishes, perhaps still opens one or the other craterlets and more Rifte poppen on how far in Holurhaun. The risk of a major outbreak has dropped enormously, Höskuldsson says in Morgunbladid.

 

Unfortunately, no link to verify what was reported in the Morgubladid; perhaps their media sources are like ours, different interpretation depending on editorial policy. I think something as important as the risk dropping enormously would have been mentioned in todays IMO briefing - the three scenarios remain as before.

[karyo]

Unfortunately, no link to verify what was reported in the Morgubladid; perhaps their media sources are like ours, different interpretation depending on editorial policy. I think something as important as the risk dropping enormously would have been mentioned in todays IMO briefing - the three scenarios remain as before.

Agreed! I was surprised to read that especially after the successive large earthquakes yesterday.

[BrickFielder]

 I personally think the tremor chart for vonasgard sil shows lower lava intrusion into the fissure. From this I would expect the eruptions to die down if it conitues. GPS time series charts to me do not suggest much in the way of the fissure opening up more or much uplift.

 

http://earthice.hi.is/gps_time_series_around_bardabunga_0

 

I thought I would do a little anlysis on the earthquakes around Bárðarbunga's caldera to see if there was a depth at which there were no earthquakes. Firstly I looked at earthquakes over the last 48 hours and picked three likely depths 4km to 4.5km and 1.7km to 2.7km and below 10km. Looking back further and I picked up earthquakes in those regions above 10km. I thought I would do some more analysis to see if larger earthquakes were on one particular part of the caldera and the answer seemed to be perhaps NE or NNE but not exclusively. Perhaps I could pick up information by analysing distance from the center of the caldera and depth or location. There was perhaps a suggestion that deeper earthquakes were more central. I guess more detailed spectral analysis of the earthquakes is required to pick up any patterns.

 

What I hoped to see was an area at the magma chamber where there were no earthquakes. Perhaps a particular weakness in the ring faulting above the magma chamber. Not finding something can off course be as informative as finding something in scientific terms. Perhaps there is no shallow magma chamber ? Perhaps the magma chamber walls are partially collapsing ? Do earthquakes potentially below a magma chamber centrally indicate opening up of dyke intrusions into the chamber and how quickly could it refill ?

 

Well at least one mistery has been partially explained and that was why the GFUM Sil GPS plot was showing a rise. The reason being that the antenna was iced up. Still when I look at the longer term plot it seems like a partial explanation (still looks like a bit of inflation and deflation allowing for correction - smothing of east/west plot movement).

 

 

Some quotes from another paper which might interest

 

The magma pressure in the shallow chamber of Bárðarbunga decreases when magma flows into the shallow Krafla chamber.
A layer of partially molten material beneath the 10-20km thick crust in Iceland is inferred from seismic and mahnetotelluric data. This layer acts as a coductor or pressure variations between volcanic systems even if their magmas do not mix.

Five of the Bárðarbunga earthquakes were large enough to allow a fault plane solution to be obtained from P-wave first motions. A common feature of all the solutions is a large component of reverse faulting.The earthquakes are therefor likely to be related to brittle failure of the crust in response to stress changes caused by pressure fluctuations in the magma chamber.

http://jardvis.hi.is/sites/jardvis.hi.is/files/Pdf_skjol/Bardarbunga_greinar/einarsson91.pdf

 

 

This suggests a magma source or plumbing system linking up icelandic volcanoes somewhere between 10-15 km deep (perhaps between the new crust and older subducted old crust ?)

It also suggests the caldera crust might be brittle, but I should point out that I think other papers would contest this.

 

It all looks to me like we will get possibly multiple phases of activity over a longer period. Perhaps phase 1 is coming to a bit of a halt. As for what is going on in the caldera I am not sure but perhaps the university of Iceland Report gives us some clues.

 

Below the centre of the caldera, material with lower density occurs, possibly a caldera fill, a subsided block or both. Existence of magma chamber is uncertain. If a shallow level magma chamber exists below the  Bárðarbunga volcano a likely location is at the base of the lower density region.

 

http://en.vedur.is/media/jar/Bardarbunga_kafli20140825.pdf

 

That sounds like some sort of collapse has happened before to me. I have also read about some gravity anomalies in Bárðarbunga which have been atributed to asperities or gabbro. So again I am not sure.

 

As ever I am not an expert and you should take everything I say with an open mind to being completely wrong.

[The PIT]

 I think we will see a continued sinking of the caldera for a little while yet but nothing catastrophic in the terms of eruption unless magma is suddenly withdrawn at a very fast rate from the magma chamber effectively emptying it. I suspect a long run of fissure eruptions to occur.

[karyo]

 I think we will see a continued sinking of the caldera for a little while yet but nothing catastrophic in the terms of eruption unless magma is suddenly withdrawn at a very fast rate from the magma chamber effectively emptying it. I suspect a long run of fissure eruptions to occur.

Enough to keep us busy for the rest of the year and the next one too!

[john pike]

Tuesday marks one month since a record wave of seismic activity started at and around the volcano of Bardarbunga. At least 20,000 earthquakes struck the area in that period, according to estimates from the Icelandic Met Office.

186 earthquakes of magnitude 3.0-3.9 were detected. 43 quakes were of magnitude 4.0-4.9, most of them at Bardarbunga's caldera. A total of 23 earthquakes were detected of magnitude 5.0 or greater, all at Bardarbunga. The largest earthquake, a magnitude 5.7, struck on 26 August. That's the largest earthquake in Iceland since a M6.3 struck east of Reykjavík in 2008.

No significant changes have been observed in the ongoing lava eruption at the lava field of Holuhraun, north of Bardarbunga volcano. Sulfur dioxide pollution from the eruption continues to plague people in the northern and eastern parts of Iceland, though it causes no immediate harm to people.

A M5.2 earthquake struck Bardarbunga Tuesday afternoon. The subglacial volcano's caldera continues to subside at a rate of 50 cm (20 inches) a day, according to scientists.

Three scenarios of future development are still considered most likely. Firstly, that the subsidence of Bardarbunga's caldera will stop and the Holuhraun eruption slowly fades out.

Secondly, the subsidence could continue, along with the eruption in Holuhraun. Another eruption could start, possibly under glacier. In this scenario, the eruption(s) could last for a longer time, with lava volume possibly measured in cubic kilometres. Should a subglacial eruption occur, explosive action and glacial floods should be expected.

The third scenario is an eruption within the Bardarbunga caldera. Scientists say such an eruption could melt large volumes of ice, causing a powerful glacial flood. Another possibility is that the water would not immediately escape the caldera, because of the volcano's previous subsidence. That meltwater would later produce a large flood. When the eruption would reach through the glacial ice above, explosive eruption with ashfall would be expected.

 

http://www.ruv.is/frett/20000-earthquakes-in-one-month

17.09.2014
The Icelandic Met Office mesasures SO2 at the eruption site and issues daily forcast on SO2 concentration in the atmosphere based on SO2 measurements and weather conditions. Today the forecast of Sulphur dioxide (SO2) concentration is high in the vicinity of the eruption and surrounding area. The pollution can be expected to move towards Hofsjökull and Tungnárjökull to the south, also around the eruption area. The pollution can accumulate in depressions in the landscape and reach high concentrations.

Weather forecast: Light variable or easterly wind and cloudy but mainly dry. East and southeast 3 to 10 m/s and some rain or drizzle later today, least in the northwest. Similar weather tomorrow. Temperature 8 to 14 degrees C, during the day.

 

http://www.almannavarnir.is/displayer.asp?cat_id=133

[john pike]

Another Video of the Eruption

http://icelandreview.com/news/2014/09/17/another-video-eruption

[john pike]

M 4.2 - ICELAND - 2014-09-17 18:09:55 UTC

 

http://www.emsc-csem.org/Earthquake/earthquake.php?id=400333

 

 

Edited September 17, 2014 by john pike

[john pike]

http://www.livefromiceland.is/webcams/bardarbunga/

 

its trying to clear

Edited September 17, 2014 by john pike

[karyo]

M 4.2 - ICELAND - 2014-09-17 18:09:55 UTC

 

http://www.emsc-csem.org/Earthquake/earthquake.php?id=400333

Quiet all day and now waking up for the evening

[john pike]

Edited September 17, 2014 by john pike

[karyo]

M 4.2 - ICELAND - 2014-09-17 18:09:55 UTC

 

http://www.emsc-csem.org/Earthquake/earthquake.php?id=400333

 Upgraded to 5.2 according to IMO

 

[john pike]

hi karyo

 

thought that was bigger than 4.2

[ukpaul]

Interestingly. no reaction from the caldera GPS.

[john pike]

http://en.vedur.is/media/jar/myndsafn/Factsheet_Bardarbunga_20140917.pdf

[karyo]

hi karyo

 

thought that was bigger than 4.2

I wonder if this is the first of several big ones like yesterday evening.

[john pike]

hi karyo

 

i would not be surprised

 

seat belts on again

[karyo]

hi karyo

 

i would not be surprised

 

seat belts on again

Last night was exciting, wasn't it? I almost thought it was about to erupt!

[john pike]

 

 

spot the red line again

 

hi karyo

 

last night certainly was interesting :)

 

what happens next??????????

Edited September 17, 2014 by john pike

[Allseasons-Si]

Evening all

 

yes it was v interesting last night,i didn't go to bed till gone 12,was up @5am

 

anyhows,what happened to to cams,was it a power outage?

[john pike]

hi allseasons

 

it looks like it was dense fog-gas blocking the view

 

http://www.livefromiceland.is/webcams/bardarbunga/

 

its trying to clear

[john pike]

Wednesday

17.09.2014 18:09:52 64.619 -17.390 5.9 km 5.2 99.0 7.0 km ESE of Bárðarbunga Wednesday

17.09.2014 15:31:09 64.664 -17.393 5.0 km 3.3 99.0 6.9 km ENE of Bárðarbunga Tuesday

16.09.2014 21:34:12 64.692 -17.378 7.7 km 5.4 99.0 9.2 km NE of Bárðarbunga Tuesday

16.09.2014 20:02:53 64.677 -17.470 5.0 km 4.8 99.0 4.9 km NE of Bárðarbunga Tuesday

16.09.2014 18:23:04 64.674 -17.460 7.4 km 3.9 99.0 4.9 km NE of Bárðarbunga Tuesday

16.09.2014 16:13:35 64.674 -17.393 6.7 km 3.7 99.0 7.4 km ENE of Bárðarbunga Tuesday

16.09.2014 14:47:57 64.621 -17.564 9.7 km 5.2 99.0 2.8 km SW of Bárðarbunga Tuesday

16.09.2014 10:36:30 64.671 -17.503 9.2 km 4.8 99.0 3.6 km NNE of Bárðarbunga Tuesday

16.09.2014 09:13:34 64.670 -17.461 5.4 km 3.4 99.0 4.6 km NE of Bárðarbunga

 

list of quakes over 3 since yesterday

 

still fairly deep according to the above (5km the shallowist)

 

http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/#view=table

[Allseasons-Si]

hi allseasons

 

it looks like it was dense fog-gas blocking the view

 

http://www.livefromiceland.is/webcams/bardarbunga/

 

its trying to clear

is that official JP,cos it came in pretty quick,also i didn't recognise the MILA sign in the bottom left,or i didn't notice cos i was glued to the center of the cam/sceen lol.

 

it is a shame that it is foggy though.