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Bárðarbunga and Askja - Volcanic Activity


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The fissure is certainly looking rejuvenated tonight! Even the flowing lava looks brighter.

Prob down to a clearer night Karyo,she does look wonderfull,maybe free flowing also(more liquider),i am just going by the lesser extent of the EQ's,i don't know.

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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

Prob down to a clearer night Karyo,she does look wonderfull,maybe free flowing also(more liquider),i am just going by the lesser extent of the EQ's,i don't know.

Part of it may be the clearer weather but there is also a 2nd vent which was not there last night. 

 

Edit: Jon Frimman just updated his blog and he confirms that a 2nd vent has opened. He is also saying that even if this fissure closes another one will be open and the activity will last for months!

 

http://www.jonfr.com/volcano/?p=4984#comments

 

Karyo

Edited by karyo
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15 September 2014 19:00 - from geoscientist on duty

Earthquake rates are similar to recent days. Around 120 events have been detected since midnight, the vast majority in the northern part of the intrusion. Some events were located in the old part of the intrusion, i.e. a bit southwest of where the dyke was bending more northerly into Dyngjujökull on 23 August. All events in the intrusion are smaller than magnitude 2.

Occasional earthquakes on the caldera rim of Bárðarbunga. No event exceeded magnitude 2 after the M5.4 this morning at 08:04. Microseismic activity around Dreki (east of Askja) continues at low rates, same at Herðubreiðartögl.

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

 

hi love snow

 

ï‚·
Three
scenarios are
considered most
likely:
o
Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun
declines gradually.
o
Large
-
scale subsidence of the caldera occurs, prolonging or strengthening
the eruption on Holuhraun. In this situation, it is likely that the eruptive
fissure would lengthen southwards under Dyngjujökull, resulting in a
jökulhlaup and
an ash
-
producing eruption. It is also possible that eruptive
fissures could develop in another location under the glacier.
o
Large
-
scale subsidence of the
caldera occurs, causing an eruption at the edge
of the caldera. Such an eruption would melt large quant
ities of ice
, leading to
a major jökulhlaup, accompanied by ashfall.

Other scenarios cannot be excluded

http://en.vedur.is/media/jar/myndsafn/Factsheet_Bardarbunga_20140915.pdf

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Could it be possible for this volcano to just switch off and go back to sleep so to speak for the next decade ? Of is it past the stage of no going back now and it will erupt ?

Nobody knows LS,the weather is more predictable than this(to an exstent),not many EQ's since the biggy this morning(quiet eery) but that doesn't meen that it is over,my take on the situation at the moment is the longer this fissure keeps erupting,the more the magma chamber empty's,and the caldara drops even more

 

on basic turms,the lava exiting through the dyke out of this fissure is releaving preasure on the bardabunga volcano,hence the collapse of the caldara,here is the link of the collapse of the caldara

 

http://brunnur.vedur.is/pub/bgo/figs/

 

you can see the drop from left to right,hope that helps

 

now did i get that right,only a novice on the subject myself. :unsure2:

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Part of it may be the clearer weather but there is also a 2nd vent which was not there last night. 

 

Edit: Jon Frimman just updated his blog and he confirms that a 2nd vent has opened. He is also saying that even if this fissure closes another one will be open and the activity will last for months!

 

http://www.jonfr.com/volcano/?p=4984#comments

 

Karyo

No it wasn't there last night Karyo,but i think it is a old fissure that has re-opened,what does that tell us,MORE PRESSURE?,or widening of the fissure fault.

 

WAIT A MOMENT,what has happened to the main lava fountain,it's died down!!,just a quick question,can these cracks/fissures open and close with the techtonic plates shifting,maybe a stupid question.

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No it wasn't there last night Karyo,but i think it is a old fissure that has re-opened,what does that tell us,MORE PRESSURE?,or widening of the fissure fault.

 

WAIT A MOMENT,what has happened to the main lava fountain,it's died down!!,just a quick question,can these cracks/fissures open and close with the techtonic plates shifting,maybe a stupid question.

I think the flow can vary according to the pressure from below i.e how much magma is coming through. The big difference for me tonight is the bright colour of the lava that is flowing away from the fissure. Very hot and liquid unlike last night which was darker, slower and colder on the surface. There must be increased SO2 emissions tonight.

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I think the flow can vary according to the pressure from below i.e how much magma is coming through. The big difference for me tonight is the bright colour of the lava that is flowing away from the fissure. Very hot and liquid unlike last night which was darker, slower and colder on the surface. There must be increased SO2 emissions tonight.

The cloud/steam was obscuring the scene when i posted,the fountain is still there me bad lol

 

un-earhtley images at the moment,looks like Mars.

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16 September 2014 10:00 - earthquakes since 16 August 2014

Earthquakes measured  00:00 16. August 2014 until  22:20 15 September 2014 are listed in table:

  all intrusion caldera Kistufell Askja HB / HBT TFJ Kverkfj. automatic ~ 25.000 - - - - - - - checked ~ 5.900 ~ 4.100 ~ 760 ~ 120 ~ 250 ~ 680 ~ 70 ~10 M3.0-3.9 186 99 74 6 2 3 1 1 M4.0-4.9 43 7 34 1 1 0 0 0 M>5.0 23 0 23 0 0 0 0 0

HB/HBT:       HerðubreiðandHerðubreiðartögl
TFJ:               Tungnafellsjökull
Kverkfj.:         Kverkfjöll
Kistufell:       Cluster north of Bárðarbunga that was active during the first days
automatic:    Automatically detected events in the whole country, number of events outside the Vatnajökull are comparably small in number, contains also false detections. Asafe number is “around 20.000 eventsâ€.
checked:      Manually revised events.

In *normal* circumstances 10.000-15.000 events occurs per year in Iceland.

 

see link its easier to read

 

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

 

from iceland met office link supplied

Edited by john pike
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 A quick update on one or two things today. First up the GPS change map from the IMO web SIte.

post-2809-0-29577600-1410881074_thumb.pnpost-2809-0-02718200-1410881062_thumb.pn

 

Preliminary analysed data by the GPS monitoring group of the Icelandic Meteorological Office, the Institute of Earth Sciences University of Iceland and GNS Science."

 

http://en.vedur.is/earthquakes-and-volcanism/gps-measurements/bardarbunga/

 

 

The first thing I notice is the change at GFUM with the GPS displacement gone from pointing towards Bárðarbunga to pointing away from it. This I would interpret as a sinking of Grimsvotn or at least the area between Grimsvotn and Bárðarbunga. This might signal an end to the intrusion of lava into the fissure or that lava is flowing into another fissure.

 

Notice also that DYNC gps measurements suggest the fissure is not really opening up that much anymore (perhaps a little bit in the last 24 hours). VONC GPS measurements continue to point to uplift either at Bárðarbunga or the southern most part of the fissure.

 

It certainly looks like something happened with the magma flow movement around two days ago (especially with the GFUM upward motion reversing) and I am unsure whether it was a stop in the flow of magma into the fissure or a stop in the magma plume or magma flowing somewhere else yet to be determined. (possibly along a new fissure to the north east of the volcano ?)

 

Next up is a picture of the Bárðarbunga GPS.

post-2809-0-77937500-1410882139_thumb.pn

 

From the university of Iceland Web Site

 

http://brunnur.vedur.is/pub/bgo/figs/

 

 

What interests me here is the movement this morning (16th) which shows a marked bounce in the caldera floor. This I think shows just how  loose the caldera floor is on the ring faults.

 

Earthquakes since mid day yesterday tending to be a little deeper at Bárðarbunga which may be attributable to ring faults going down from the magma chamber down to a deep magma source. I am guessing here not only does the the caldera floor sink under decompression but perhaps the magma chamber floor does as well. This might let more magma into the magma chamber, so you get a yo yo effect between compression and decompression. Todays earthquakes seem shallower at Bárðarbunga suggesting perhaps a period of decompression again.

 

I have been reading around again through various bits and pieces which some may like to peruse and think about.

 

 

The location of maximum stress at Bardarbunga fluctuates along the chamber/ring-fault boundary in harmony with dike size and/or pressure changes and encourages ring-dike formation and associated magma flow within the chamber. Caldera collapse and/or eruption in some of these volcanoes is possible, most likely in Bardarbunga, but depends largely on the future development of the regional dike.

http://link.springer.com/article/10.1007/s00445-014-0869-8

 

 

This particular extract from an article seems to partially explains why the fissure seems to change course as it approches Askja and how stresses interact with Bardarbunga.

 

 

Our results favour outward-dipping fault segments in the western half of the ring fault, while the eastern half is preferentially inward-dipping. This variability may reflect structural heterogeneities or an irregular magma chamber geometry. The individual segments of the caldera ring fault radiated approximately equal amounts of energy. This indicates that the caldera dropped coherently as one single block.

http://www.sciencedirect.com/science/article/pii/S0012821X10004516

 

This one interests me because it indicates the change from inward to outward dipping ring faults is from east to west and implies rather than fragmentation of the caldera floor you might expect the whole caldera floor to move as one. This could imply a very slow collapse of the caldera is likely or that reinflation of the magma chamber could cause problems. I am of course just guessing again or hoping.  A very rapid caldera collapse could be very nasty but seems less likely.

 

The initiation of the collapse on June 11 was accompanied by  a major explosion recorded by infrasonic stations throughout the western hemisphere.

http://gji.oxfordjournals.org/content/39/2/301.full.pdf

 

This interests me because it suggest perhaps you can have an infrasonic wave or pressure wave associated with a caldera collapse.

 

Bearing in mind the worst case scenario of a rapid caldera collapse seems unlikely due to a mixture of outward and inward dipping ring faults. What do you think would be the effects of the worst case scenario  (earthquake big enough to affect the UK? tsunami ? a pressure wave ? big sulphur dioxode cloud ? ash ?). Just curious for peoples opinions.

 

As ever anything I post should be taken with a very large pinch of salt and I openly admit the situation has me totally confused and I dont have the training to interpret the information  kindly provided by the authorities in Iceland.  I just hope better minds can explain the anomalies and puzzles I see.

 

 

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Quote Brickfielder.

 

 

It certainly looks like something happened with the magma flow movement around two days ago (especially with the GFUM upward motion reversing) and I am unsure whether it was a stop in the flow of magma into the fissure or a stop in the magma plume or magma flowing somewhere else yet to be determined. (possibly along a new fissure to the north east of the volcano ?)

 

The Institute of Earth Sciences have said that the erroneous movement was caused by ice build up on the instruments.

 

lOlxtVH.png

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