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CaptainToonces
2014-Aug-20, 05:44 AM
There are a lot of earthquakes happening around the Bardarbunga volcano lately. Are we about to see an eruption some time in the next few days?

The wiki articles are pretty lacking but I found this cool page: http://hraun.vedur.is/ja/englishweb/vatnajokull.html

According to this, if it's correct, there seems to be a lot of seismic activity going on just in the last few hours.

Squink
2014-Aug-20, 12:22 PM
That's a big swarm alright!
Area north of Bardarbunga evacuated (http://www.cbc.ca/news/world/iceland-volcano-area-north-of-bardarbunga-evacuated-1.2741422)

CaptainToonces
2014-Aug-20, 01:13 PM
This site may be even cooler. You can click on the graph and drag it to rotate in 3d:

http://baering.github.io/

dgavin
2014-Aug-20, 02:26 PM
I have not found the VONA source for this mountain yet, as it's buried in universities web site, that's more interested in advertising then giving access to their data. Anyway I have found that it's been upgraded to condition orange (Eruption imminent). The area north of the volcano has been evacuated, and the Icelandic Coast Guard has searches underway for hikers and other missed during evacuation.

A magma reservoir has been confirmed from 3km to 7km depth, though no dimensions on it's total volume yet. However given the size in depth alone it could be capable of anything from a VEI 2 to 7 level eruption.

Normally I'd side with a VEI 3 for this, due to the rift nature of the magma in Iceland. However with a half mile of ice above it, I'm going to have to say this might be the first VEI 6 to 7 in our life time, likely mostly from a steam blast eruption that blows a crater out the overlying glacier, and not so much ash.

If this mountain does erupt, as it sits under about a half mile of ice, it could trigger one of the largest glacial melt's seen in about 12000 years.

Squink
2014-Aug-21, 02:55 PM
Iceland Met Office (http://en.vedur.is/) is keeping pretty good track of quakes (http://en.vedur.is/earthquakes-and-volcanism/earthquakes#view=table).
4.0 and 3.8 this morning (http://icelandreview.com/news/2014/08/21/magnitude-40-earthquake-bardarbunga).

dgavin
2014-Aug-22, 03:51 AM
I checked some historical data, and this mountain occasionally has produced a VEI 6 level eruption.

danscope
2014-Aug-22, 03:59 AM
That's a lot of steam and water.... along with the attendant ash and gases. No good comes from a vei6 .

dgavin
2014-Aug-22, 04:39 AM
What I have found out from an independent Icelandic geologist's web site.

While there is GPS uplift north of Bardarbunga and magma moving to the north in an underground dyke, that the Bardarbunga caldera is starting to subside, at a increasing pace. This indicate a (remotely) possible caldera collapse is starting. However while there are harmonic tremors and earthquakes. There are only a few signs of upward magma displacement, and not enough to be concerned over There are also no signs of any Chugging, which means the magma chamber while depressurizing to the north, it is not showing the chugging signature of Magma moving into a volcanic chimney.

It's hard to say what this mountain will do exactly, but with magma being force to the north, and the caldera itself subsiding, I'd have to agree with Jon Fr.'s assessment on his site, that this might, just might be the first caldera collapse being monitored ever by seismologic equipment and web cams. Time will tell if that assessment turns out accurate.

*edit to add*

Incase anyone asks, there has never been a caldera collapse less then a VEI 6 level.

dgavin
2014-Aug-22, 05:00 AM
4.7 magnitude 21 Aug 23:50:20 Checked 4.0 km SEof Bįršarbunga

dgavin
2014-Aug-22, 03:10 PM
Iceland Met Office has now also confirmed the caldera subsidence.


Large events in Bįršarbunga are interpreted as adjustments of the caldera rim related to decompression in the caldera since the beginning of the unrest. The activity continues and an eruption can therefore not be ruled out.

During the last days quite a number of quakes has been detected within the Bįršarbunga caldera, or on the rims, at a depth of 2-6 km. Probably these earthquakes derive from changes in pressure when magma is drawn eastward into the huge intrusion and away from the magma chamber under the caldera.

Squink
2014-Aug-23, 02:13 AM
Intrusion is large dyke formation (http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947):
A 25 km long dyke has formed in the crust under the Dyngjujökull glacier at 5-10 km depth. Interpretation of the latest data suggests that the magma continues to move along the dyke, possibly branching at the northeast end of the dyke.

CaptainToonces
2014-Aug-23, 03:46 AM
Almost a week since the earthquake swarm began and no signs of slowing down. Good thing Yellowstone isn't doing this :)

And we are 3 days away from the new moon, when tidal forces will be at their peak.

Squink
2014-Aug-23, 05:20 PM
It is believed that a small subglacial lava-eruption has begun under the Dyngjujökull glacier. (http://en.vedur.is/) The aviation color code for the Bįršarbunga volcano has been changed from orange to red. (Met office front page warning banner)

Looks like baseline tremor size picked up half a magnitude unit or so around 10 (http://en.vedur.is/earthquakes-and-volcanism/earthquakes) this morning (saturday).

CaptainToonces
2014-Aug-24, 02:01 PM
The aviation threat code was reduced from red to orange today, but seismic activity actually increased. Two 5.0+ magnitudes today.

Squink
2014-Aug-24, 07:51 PM
Met office has walked backed yesterday's claim of subfglacial lava flow.

CaptainToonces
2014-Aug-25, 08:09 AM
Magnitude 6 quake north of San Francisco yesterday, and a 7 in Peru. Moon about 4 hours away from the new-moon peak alignment with the Sun as I type this, which will coincide with mid day in Iceland. No solar eclipse will be visible from Earth for this month's new moon, as the declination of the Earth, Moon, and Sun bodies are offset too much.

I do expect a day of heavy seismic activity in Iceland. Get your popcorn ready and tune in around 7:00am if you live in the US.

dgavin
2014-Aug-26, 04:03 AM
The Caldera subsidence quakes are getting stronger.



5.3
24 Aug 20:39:11
Checked
8.1 km E of Bįršarbunga


5.1
24 Aug 05:33:41
Checked
4.6 km SE of Bįršarbunga


4.8
24 Aug 15:00:11
Checked
5.0 km SE of Bįršarbunga

CaptainToonces
2014-Aug-26, 08:18 PM
This is really an unprecedented event, scientifically. I don't think the movements of magma through the Earth's crust have ever been tracked nearly this well, and likewise no magma event like this has ever been scientifically observed.

Squink
2014-Aug-26, 10:59 PM
Nice compilation w maps etc at Daily Kos: 40km Long Fissure Is Ripping into Violent Askja, Linking Iceland's 3 Largest Volcanoes: Updated (http://www.dailykos.com/story/2014/08/25/1324426/-40km-Long-Fissure-Is-Ripping-into-Violent-Askja-Linking-Iceland-s-3-Largest-Volcanoes?detail=hide)
vulcanologists have been stunned by the growing 35 - 40km long dyke which now connects the fissure systems of Iceland's three largest volcanoes. As a general rule, eruptions stay on the fissure systems of one volcano because magma will follow a fissure system's existing planes of weakness. The forces controlling the movement of magma now are acting on a larger scale than the scale of one volcano. While Iceland's Met office is speaking calmly of a possible small eruption other vulcanologists are discussing the possibility of a large rifting eruption

50 million cubic meters of magma was injected into the dyke system yesterday. (http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947)That's 0.05 cubic km a day or 18.25 cubic km per year.

Squink
2014-Aug-27, 02:18 PM
Activity is definitely slacking off. Whole country magnitude 3 or greater over 48 hours was up to 89 this past weekend. It's down to 29 today (http://en.vedur.is/earthquakes-and-volcanism/earthquakes#view=table).

JohnD
2014-Aug-27, 09:16 PM
This is interesting - and terrifying:

https://www.youtube.com/watch?v=dQWzLPyRY8I

It maps the earthquake epicentres that mark the dyke (is 'magmatube' a word?) that has been moving.
It's moving straight towards Lake Askja, a caldera lake that is the deepest in Iceland and the remains of a volcano that erupted in 1875, so enormously that large numbers of Iclanders emigrated to Manitoba, to found 'New Iceland'.

If that dyke reaches the Lake - Kablooey?

John

profloater
2014-Aug-27, 11:56 PM
Interesting indeed and I have been shocked to see no sign of it in any news broadcast, New Scientist had a small paragraph this week, that's all.

dgavin
2014-Aug-28, 12:53 AM
Meanwhile at the Bardabunga Caldera: 5.4 and a 5.2 Mag quakes today.


Scientists from IES and IMO on a flight to Vatnajökull tonight discovered a row of 10-15 m deep cauldrons south of the Bįršarbunga caldera. They form a 6-4 km long line. The cauldrons have been formed as a result of melting, possibly an eruption, uncertain when. Heightened tremor level/volcanic tremor has not been observed on IMO's seismometers at the moment. The new data are being examined.

Possible Steam Fissure or Magma Fissure emissions underway... This is exactly what is expected as a precursor to a caldera collapse.

Squink
2014-Aug-28, 01:49 PM
Intrusive Dike Reaches Askja Fissure Swarm (http://icelandreview.com/news/2014/08/28/intrusive-dike-reaches-askja-fissure-swarm)
The intrusive dike formed by magma flowing out of the Bįršarbunga caldera keeps extending to the north and has now reached the fissure swarm of the Askja volcanic system, according to Kristķn Vogfjörš, director for research at the Iceland Met Office.

Squink
2014-Aug-29, 02:57 AM
Breaking News: An Eruption has Started for Real (http://icelandreview.com/news/2014/08/29/breaking-news-eruption-has-started-real)
At midnight on August 28 a small fissure eruption started the Holuhraun lavafield,approximately mine kilometers north of Dyngjujökull glacier. First indications are that the lava streams out of a 100 meter long crack, about 15 kilometers south of the Askja caldera
The Events Leading to the Eruption (http://icelandreview.com/news/2014/08/29/events-leading-eruption)
Webcams (http://www.livefromiceland.is/)

CaptainToonces
2014-Aug-29, 09:03 PM
There seems to now be significant evidence that all of the intrusions have their own linkage to the mantle underneath, and are not necessarily all flowing from Bardarbunga as was speculated by some. So the fact that the earthquake swarm followed the line of the continental rift "from" Bardarbunga "to" Askja may simply have been a visual red herring, as they all lie on the line of the rift.

http://i1049.photobucket.com/albums/s396/gogglezon/Deep_zpse3360462.jpg


Each translucent orange circle represents an earthquake observed since Aug 16th 2014.

JohnD
2014-Aug-29, 09:17 PM
The eruption has started. Magma on the surface:
http://icelandreview.com/news/2014/08/29/breaking-news-eruption-has-started-real

dgavin
2014-Aug-30, 05:43 AM
To make matters worse, the remains of storm "Cristobal" will be making landfall in Iceland Sunday. Talk about a double whammy....

dgavin
2014-Aug-30, 06:34 PM
Ash visible on both Bardarbunga webcams today. hey were complete obscured by as earlier, but there some visibility now.

JohnD
2014-Aug-30, 08:55 PM
Just to point out.

The fourth letter of the word for this volcano is not a 'd' but an 'eth', a letter in the Nordic alphabet that looks like a 'd' with crossed upright and pronounced as an unvoiced 'th'.
Here's help from a friendly Icelander! https://www.youtube.com/watch?v=o5t96V-8_TM

John

dgavin
2014-Aug-31, 05:46 PM
Was watching the web cam this morning when I caught an eruption on cam, snap shot (Courtesy of Mila Communications) attached. It's still going strong, and looks like the fissure is near 1km long now total.

Squink
2014-Aug-31, 07:46 PM
the flow of lava is close to 1,000 cubic meters per second (http://icelandreview.com/news/2014/08/31/lava-flow-four-times-eyjafjallajokull), which is three to four times the flow during the 2010 Eyjafjallajökull eruptionThat's about 7.5 cubic miles (31.5 cubic km) per year.

dgavin
2014-Sep-01, 09:07 PM
Still not a lot of ash fall, but the fissure eruption continues at around 100 m3/sec. 2 more > 5 mag quakes in Bįršarbunga Caldera, Iceland Met office has indicated today that an eruption in the Caldera also is possible.

JohnD
2014-Sep-02, 12:18 PM
Live webcam of the beginning eruption at: https://www.youtube.com/watch?v=zKtGqoxV_qo#t=7855

Click on the 'Live' dot, bottom line, to make it red and live.
Just smoke now, it was dramatic last night!
JOhn

CJSF
2014-Sep-02, 06:12 PM
Just to point out.

The fourth letter of the word for this volcano is not a 'd' but an 'eth', a letter in the Nordic alphabet that looks like a 'd' with crossed upright and pronounced as an unvoiced 'th'.
Here's help from a friendly Icelander! https://www.youtube.com/watch?v=o5t96V-8_TM

John

Languages sometimes really just throw me.... if it's an "unvoiced" sound, doesn't that mean silent? How can it sound like a "th" if it's unvoiced??

Anyway, thanks everyone for keeping up on this - the web cam views have been awesome and it's good we have people with relevant expertise (or at least a lot of interest) on the forum.

CJSF

Strange
2014-Sep-02, 06:54 PM
Languages sometimes really just throw me.... if it's an "unvoiced" sound, doesn't that mean silent? How can it sound like a "th" if it's unvoiced??

It means your vocal cords don't vibrate.

Thin is unvoiced.
This is voiced.

S is unvoiced (actually it depends, it is unvoiced and then voiced in horses, for example).
Z is voiced.

F is unvoiced.
V is voiced.

CJSF
2014-Sep-02, 06:57 PM
Hmm... :think: ok.. I get it... I think. Thanks.

CJSF

Squink
2014-Sep-02, 08:16 PM
The rate of deformation at GPS sites closest to the dike intrusion has decreased. Together with an overnight decrease in seismicity, this implies that magma inflow appears to match magma outflow (http://icelandreview.com/news/2014/09/02/slight-decrease-eruption-activity) at the eruption site. Number of tremors over the past day is roughly half that of previous days.

dgavin
2014-Sep-03, 01:48 PM
Strongest quake in the Caldera, at 5.5 mag this morning. So far all these large quakes in the caldera have been along the caldera's rim. This is expected of both just subsidence, or as precursor to a caldera collapse. Also it appears that recent measurements indicate that the magma inflow into the dyke from the Caldera, is still larger then what is erupting at the fissure.

dgavin
2014-Sep-04, 02:04 PM
Iceland Met reporting that the tremors at fissure site have stopped today, though lava is still extruding. Quakes at the Caldera still continuing.

Trebuchet
2014-Sep-04, 02:59 PM
I've gotten the impression that a fissure eruption is less dangerous than a caldera eruption. Less ash, or something. Is that correct?

JohnD
2014-Sep-04, 08:57 PM
http://www.livefromiceland.is/webcams/bardarbunga-2/

Extreme telphoto lens, so a little shaky. Not as dramatic as before but still erupting, and in the night dramatic enough. Is that a lava flow from bottom middle towards the left?
JOhn

Swift
2014-Sep-05, 01:09 PM
I have to admit when I look at the URL for that link my brain wants to interpret it as Live Fro Mice Land :doh:

dgavin
2014-Sep-05, 02:09 PM
Trebuchet, Yes Fissure eruptions tend to be safer, unless you get to one that is size of the Siberian or Decan Traps, or the Columbia River Breakout. Then ash isn't the problem, but the sheer amount of C02 and SO2 pumped into the atmosphere.

JohnD, Yes that is the Southern area of the flow. Most of the Lava is heading away from the Cam's to theright and beyond into the flats.


Two new lava vents have opened up in that Southerner flow area but with minimal fountaining. Tremor activity has been off an on. The Caldera itself is still experiencing quakes, in a pattern around the rim. Another 5.3 magnitude today. That does not seem to be slowing down, so if this level of quake activity continues over then next month in the caldera, I'd place a guess at a 15% probability of a caldera collapse.


It's low, because, this is likely just what is known as a lateral eruption, where the magma breaks out of the side instead of the top of the volcano. Just this is a very odd one in that the magma traveled some killometers before breaking out. As to how that happened, I'd also guess there was a lava tube down there in place, and there was a EQ that opened up a way between the tube, and the Caldera's magma chamber. There is a Lava tube (TomSawyer Caverns) in Oregon, that's been explored in to 2 miles, and it's assumed from measurements that it goes some 28 miles all the way back to Mt. Jefferson. So a pre-built tube already there is a distinct possibility.

Squink
2014-Sep-06, 02:19 PM
Short Subglacial Eruptions have occurred (http://icelandreview.com/news/2014/09/06/short-subglacial-eruptions-have-occurred)
In the surveillance flight yesterday the ice-surface at Bįršarbunga was measured with the radar system of Isavia's aircraft. The measurements show large changes on the ice-surface. Up to 15 m subsidence has occurred in the centre of the caldera, which corresponds to a volume change of 0.25 km3. The shape of the subsidence area is in accordance with the elevation of the caldera floor having lowered by that amount.

Subsidence of this order has not been observed in Iceland since measurements of crustal movements started around the middle of last century. Story includes a nice map.

dgavin
2014-Sep-06, 03:23 PM
Wow, chances of a caldera collapse....now my guess is about 25% with that information. Hadn't realized the subsidence was that significant.

dgavin
2014-Sep-07, 04:14 PM
From Ice Met Office today,
The lava tongue now extends 11 km to the north and has reached the western main branch of Jökulsį į Fjöllum river. Also there was a mag 5.4 at the caldera rim.

CaptainToonces
2014-Sep-09, 12:00 AM
More big quakes around the caldera today. I figure it's gotta fall in at some point.

dgavin
2014-Sep-09, 12:38 AM
Iceland met staff that were field camping at the oasis at Mt. Heršubreiš, had to evacuate that area today after swarm of quakes occurred there, followed by a significant increase in CO2 emissions. Heršubreiš is about the same distance from the lava flows, as the flows are from the caldera, sort of making the flows the central point of activity in that area.

Squink
2014-Sep-10, 03:46 PM
More big quakes around the caldera today.
5.2 yesterday and 5.5 today. Caldera continues to sink.

dgavin
2014-Sep-12, 01:57 AM
Another 5.2 Today. Additionally Iceland Met office is now indicating that either a Large Scale Caldera subsidence might occur, causing the fissure to expand and erupt much stronger. Or, also considered as likely, a Caldera Collapse. Bumping my guess for Caldera collapse up to 33% probability.

CaptainToonces
2014-Sep-12, 09:20 AM
33% seems low to me. I am a layman, but we've been seeing magnitude 5 quakes on a daily basis underneath the caldera for weeks now.

The magma, it seems, has tried to escape from lower altitude points nearby, but it's still exerting tons of pressure on the glacier and earth holding it down over Bardarbunga caldera.

How many mag 5 earthquakes does it take for the ice to fall into the molten rock?

dgavin
2014-Sep-12, 01:44 PM
Well, to be honest, how many does it take? It's completely unknown. The last Caldera collapse that was documented was Krakatoa, and there was no monitoring of that one. They don't happen often enough for a good baseline on them. Like St. Helens which was the first well monitored strata volcano eruption, Bardarbunga if it collapses, will be new science!

dgavin
2014-Sep-12, 01:54 PM
On that note, the number of larger earthquakes at the caldera have been increasing very slightly in frequency and in strength. If what was learned from strata volcanoes that blow out, applies with a caldera, a large scale subsidence or collapse may involve a magnitude 6 to 8 quake event. So far the strongest event's have been a few 5.4mag.

Gillianren
2014-Sep-12, 02:22 PM
Well, to be honest, how many does it take? It's completely unknown. The last Caldera collapse that was documented was Krakatoa, and there was no monitoring of that one.

Also not a lot of ice.

dgavin
2014-Sep-13, 02:52 PM
From Iceland Met office:
The GPS station on top of Bįršarbunga shows a subsidence of the caldera around half a meter over the last 24 hours.

Unknown if this is a trend increase, or a one time increase. A half meter of a caldera that size, is a fairly significant shifting of mass.

dgavin
2014-Sep-13, 03:12 PM
The closest web cam is transmitting nothing but white today. I would guess that it finally broke down due to all the shaking from tremors.

JohnD
2014-Sep-13, 04:38 PM
"Half a meter", dgavin?

The caldera has subsided by FIFTEEN meters, equivalent to 250 million cubic meters of magma.

See: http://www.ruv.is/frett/15-meter-subsidence-in-bardarbunga-caldera

"This much subsidence has never before been measured in Iceland," says geophysicist Magnus Tumi Gudmundsson, a professor at University of Iceland“s Institute of Earth Sciences, "We have not measured an event like this before in Iceland. We probably have to go back to the formation of the Öskjuvatn caldera in Askja, in 1875, when a large explosive eruption occurred there. That event was of course much larger, with subsidence of about 300 meters, but the current one in Bardarbunga is ongoing, and very significant."
And Askja was an enormous event, that led to thousands of Icelanders emigrating to the USA: http://www.icelandicroots.com/%CF%89-the-luck-of-the-icelanders-%CF%89/

JOhn

dgavin
2014-Sep-13, 05:32 PM
Might want to read what I posted a little better, about the 1/2 meter being in just the last 24 hours......

Total subsidence is actually over 20m as of today.

JohnD
2014-Sep-14, 12:13 PM
Oops, sorry, DG!

Whats the implication of this magma loss? Has it all 'leaked out' into the fault pointing towards Askja, in a sort of safety valve, depressurising a dagerous situation, or is this a precursor of a far more dangerous one? The Icelandic authorities are comparing with the Askja event, which was in a group with Mt.Helen's and second only to Kratatoa and Tambora.
What's your bet?
JOhn

dgavin
2014-Sep-14, 04:10 PM
Based on all information, my gut feeling is I don't think we are going to see an explosive caldera collapse.

Activity at the fissure has reduced down to a single vent/cinder cone and the lava flows are slowing down.

While the Caldera subsidence has reached 23 Meters (75.5 Feet) which is extreme, and has never been seen before in a documented fashion, all appearances say the subsidence is purely based on the magma pool having already been drained into the dyke and fissure.

I think we will see the fissure activity stop at some point -first-, and then some weeks later, the caldera subsidence will settle down. I will go out on a limb and say the subsidence will probably never reach 50m.

While the SO2 emissions are still very high, there has not been any emissions from the rim of the Caldera itself, or other signs indicating an explosive eruption potential there yet.

I honestly think what we are seeing here, is how Caldera subsidence/formation normally works. With the explosive formation of say Crater Lake, being much more rare of a event.

profloater
2014-Sep-14, 04:24 PM
Question: I had thought before that Crater Lake, for example, was formed by collapse of a volcano cone into the lava pool beneath, forming the Caldera, subsequent activity of the Caldera such as Yellowstone can heave up and down as lava flows around. Is it the addition of large amounts of water flooding into the lava pool that makes explosion possible, let alone likely?

Squink
2014-Sep-14, 08:13 PM
Based on all information, my gut feeling is I don't think we are going to see an explosive caldera collapse.Most of the larger quakes have been on the caldera's north and southeast sides. Crater floor looks to be behaving like a cork jamming in a bottle sideways. A 6.5 off to the west side could still change that pretty quickly though.
The one cone that's still active (Baugur) is now is over 200 feet tall. That'll change the character of what we see on cam without necessarily meaning less lava is flowing.

Trebuchet
2014-Sep-15, 12:39 AM
Phil Plait has a post up about a "Volconado (http://www.slate.com/blogs/bad_astronomy/2014/09/14/volcano_tornado_video_of_a_vortex_spawned_by_the_i celand_eruption.html)" at Bardarbunga. Wait 'til the Discovery Channel gets ahold of that! SharkoVulcoNado, or something.

dgavin
2014-Sep-15, 01:57 PM
Is it the addition of large amounts of water flooding into the lava pool that makes explosion possible, let alone likely?

Although magma's can change by it encountering water as it pushes to the surface. Basically there are three types. Gas content drives the potential for explosive eruptions.




Summary Table




Magma Type


Solidified Rock


Chemical Composition


Temperature


Viscosity


Gas Content




Basaltic


Basalt


45-55 SiO2 %, high in Fe, Mg, Ca, low in K, Na


1000 - 1200 oC


Low


Low




Andesitic


Andesite


55-65 SiO2 %, intermediate in Fe, Mg, Ca, Na, K


800 - 1000 oC


Intermediate


Intermediate




Rhyolitic


Rhyolite


65-75 SiO2 %, low in Fe, Mg, Ca, high in K, Na.


650 - 800 oC


High


High









Source:http://www.tulane.edu/~sanelson/Natural_Disasters/volcan&magma.htm

Squink
2014-Sep-15, 04:42 PM
Photos of Lava Flowing into River (http://icelandreview.com/news/2014/09/15/photos-lava-flowing-river)

dgavin
2014-Sep-15, 05:23 PM
Rate of subsidence of Caldera in last 24 hours, 50cm (1/5 meter). Two > 5.0 quakes. While the fissure seems to have stabilized into a single cone, the caldera subsidence doesn't seem to be deceasing, but still on the increase.

CaptainToonces
2014-Sep-17, 06:24 AM
The seismic activity below the big caldera picked up again today. We had 2 magnitude 5+ quakes in the last 24 hours and several more 3 and 4 mags.

Something's going on down there. In my layman's mind, I picture high pressure magma melting the mountain of rock and ice that sits atop of Bardarbunga from below. As the caldera sinks in (I think it's gone down by almost 20 meters in altitude since this event started), its tremendous weight keeps acting as an effective plug on the magma pressure below.

But something below keeps causing the quakes and slippage so I picture it slowly melting the rock above and sending small upwellings of magma through the cracks at the weakest points in the mountain. As it does so, fault-lines are created, the earth slips in, and a big quake is generated.

So I see the question as, will the pressure from within the Earth somehow dissipate before the plug that is the glacier is breached, or will we see a small eruption, followed by accelerated melting and ultimately a climactic "big one" as the caldera collapses into a magma pool below it?

And how long is it possible all this could take?

dgavin
2014-Sep-18, 01:22 AM
The seismic activity below the big caldera picked up again today. We had 2 magnitude 5+ quakes in the last 24 hours and several more 3 and 4 mags.

Something's going on down there.

You are right, it appears the now 50cm per day subsidence is corresponding to GPS measurements (released today) indicating that the magma flow either out of or into the Caldara (uncertain as to which one) has been changing.

CaptainToonces
2014-Sep-18, 05:18 AM
Or perhaps the magma is just there, whether flowing in or out, and the cold rock and ice at the bottom of the mountain/glacier is being melted away into the magma.

At high enough temperature, the rock and ice will lose its crystalline structure and become more like a liquid. That would explain the sinking of the great ice and rock cathedral that is Bardarbunga. Its foundation is melting.

It would be interesting to see infrared pictures of the area, to measure the change in heat... and even better if we could measure the change in heat about a kilometer beneath the surface. I don't know if that's data that can be obtained though.

dgavin
2014-Sep-23, 02:49 AM
Stats so far: 0.4 to 0.6 cubic km of lava has been erupted, spanning 37 square km.

Lava flow has split into two flows, going around the area of the already extruded flow.

Caldera Subsidence continues a rate from .25m to .5m per day, total subsidence about 27.5 m (Projected from Sep. 14th last published measurement)

5.5 mag Caldera quake on the 21st.

JohnD
2014-Sep-23, 11:49 AM
Today's APOD (23/9/14) shows how much light the eruption is putting out.
That's NOT a sunset!
http://apod.nasa.gov/apod/

John

CaptainToonces
2014-Sep-23, 10:05 PM
The large quakes under the caldera have been definitively linked to subsidence of the caldera's altitude.

Still though, at 500 centimeters of sinking per day, and these quakes averaging about 5 km of depth (is that correct?), that's still several years until caldera top meets magma...

dgavin
2014-Sep-24, 02:28 AM
Well the deepest known Caldera is Crater Lake at 593m (1900+ feet) and that was from a catastrophic collapse. So I expect that this one will not subside much given the current gentle trend of it. I'll stand by my 50m max subsidence estimate for now, though it is getting closer to that mark.

Swift
2014-Sep-24, 02:58 AM
Today's APOD (23/9/14) shows how much light the eruption is putting out.
That's NOT a sunset!
http://apod.nasa.gov/apod/

John
Wow. New desktop for the home computer.

dgavin
2014-Sep-27, 01:38 PM
Updated stats. Lava flow from central cone continues, and still split off into two fields on each side of prior flows.

Avg. Daily Caldera Subsidence .45m (7m over 15.5 day as a base line) has continued. Last total GPS Subsidence measurement of 24.5m on Sept 17th. Projected out to current day, 30m (96ft) Subsidence.

CaptainToonces
2014-Oct-01, 04:47 AM
Anybody got a read on if the quakes under Bardar are getting any shallower?

dgavin
2014-Oct-01, 01:04 PM
They don't seem to be getting shallower, the quakes seems to be stable around the 4-10km range, with an occasional one above that.

Squink
2014-Oct-02, 02:21 AM
Looks like a lull tonight.
Not many earthquakes: two of magnitude 1 in last 5 hours (http://en.vedur.is/earthquakes-and-volcanism/earthquakes#view=map) (around 00 thursday).
Not much activity at fissure (http://www.livefromiceland.is/webcams/bardarbunga-2/) either since darkness fell.

JohnD
2014-Oct-02, 06:36 PM
Anybody got a read on if the quakes under Bardar are getting any shallower?

Gallant Capt. T!

It's BarTHar! BarTHarbunga!!!
JOhn

Squink
2014-Oct-02, 11:11 PM
New cluster of quakes up on the north coast of the island today (http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947) (Oct 2):
Seismic activity has been prevalent in Öxarfjöršur (Axarfjöršur) bay off the northern coast of Iceland, about 5-10 km southwest of the village Kópasker. The largest was 3.3 at 09:03 this morning.
Map of Mid-Atlantic ridge through Iceland (http://en.wikipedia.org/wiki/Mid-Atlantic_Ridge#mediaviewer/File:Iceland_Mid-Atlantic_Ridge_Fig16.gif).
Quake map (http://en.vedur.is/earthquakes-and-volcanism/earthquakes#view=map).

CaptainToonces
2014-Oct-03, 10:58 PM
Gallant Capt. T!

It's BarTHar! BarTHarbunga!!!
JOhn

Hmm, maybe they should translate it that way then! I'll refer to it as Bartharboonka from now on.

JohnD
2014-Oct-04, 09:14 AM
Icelandic uses the "thorn", a crossed 'd' for that soft 'th' sound, that English doesn't bother to discriminate from thr hard version.
"the, their, them" soft; "thing, think, cloth" hard.

Here's a helpful Icelander!

http://www.youtube.com/watch?v=o5t96V-8_TM

JOhn

dgavin
2014-Oct-09, 01:14 PM
Subsidence continues at the .45m/day rate, projected out to 35.4m total so far. While the quake activity at the fissure area has slowed, the lava flow hasn't. SO2 emissions reached Iceland's capital yesterday.

Swift
2014-Oct-14, 06:04 PM
National Geographic on-line article about erruption (http://news.nationalgeographic.com/news/2014/10/141013-iceland-volcano-bardarbunga-lava-science/)


A tremendous gush of lava in Iceland that began six weeks ago shows no signs of slowing. The eruption, on a plain of old lava called Holuhraun in the Bįršarbunga volcanic system, has spewed out enough molten rock so far to fill 740 Empire State buildings and has buried, on average, an area the size of an NFL football field every 5.5 minutes.

At this rate, the lava flow will soon be larger than any seen for more than two centuries in the volcanically active island nation. And there's no telling when it will stop—months, maybe, or years.

"It's amazing that it has gone on at this rate for so long," says volcanologist John Stevenson of the University of Edinburgh.

dgavin
2014-Oct-15, 12:24 AM
I am thinking that I am going to have to eat my words soon, that it wouldn't reach 50m subsidence...

Squink
2014-Oct-16, 11:11 PM
Last few days there looks to be a swarm of earthquakes (http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/) at Tungnafellsjökull (http://www.vidiani.com/maps/maps_of_europe/maps_of_iceland/detailed_road_map_of_iceland.jpg). It's that small glacier/volcano just northwest of Bįršarbunga caldera. Back in late 2013. a swarm there (http://www.jonfr.com/volcano/?p=4096) was put down as likely due to increased magma flow into the volcano. With the current eruption steady, and the dike so quiet, I wonder if we might soon be seeing a little eruptive activity from this new location.

Squink
2014-Oct-24, 04:06 PM
Tungnafellsjökull has settled down. However in last 48h there've been 73 quakes of magnitude 3+ all around the caldera rim (http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/).
Last week the number was more like 20-30, so there's a definite uptick.
subsidence of the caldera continues with similar rate as it has done over the last few weeks (http://en.vedur.is/media/jar/Factsheet_Bardarbunga_20141024.pdf)

dgavin
2014-Oct-24, 09:08 PM
Total Subsidence projected to 42meters now. Only 8m from my "It won't get to 50m" statement.

I better start looking for some crows to fix for supper....

CaptainToonces
2014-Oct-26, 05:34 AM
42 meters, wow. From what i understand, the rock that is this "plug" of a caldera atop Bartharboonga is vast, like an immense amount of Earth. So the energy displacement for that small island to fall 42 meters is quite off the charts.

CaptainToonces
2014-Oct-27, 03:09 AM
So why is the subsidence rate of the caldera so remarkably linear?

dgavin
2014-Oct-27, 07:29 AM
Well, this is kind of like the first Caldera collapse being so well monitored, that isn't an explosive event.

Let me research this on before chiming in on it, but I suspect that it's related to how the magma pool is draining at a somewhat linear rate.

dgavin
2014-Oct-27, 02:03 PM
I've found 3 articles and one paper detailing Linear Subsidence of Caldera's. http://adsabs.harvard.edu/abs/2014EGUGA..1612534T

So it seems that a Linear collapse of Caldera's may actually be more common than destructive collapses. It could be that destructive collapses are precipitated by a phase of Linear Subsidence, that is punctuated by an intense eruption around the Caldera. Aka, Krakatoa and Crater Lake.

Squink
2014-Nov-03, 01:33 PM
At about 66 square km, Bįršarbunga still has a ways to go to reach record size.
Today's EPOD (http://epod.usra.edu/blog/2014/11/wolly-fringe-moss-over-icelands-lava.html):

largest lava flow in recorded history, the Skaftareldahraun lava flow in southern Iceland. The flow covers approximately 232 sq mi (600 sq km) with the moss as thick as 1.6 ft (0.5 m) in some places (left). The lava flow was created during the Laki eruption of 1783. This fissure eruption lasted 8 months and resulted in a drop in global temperatures...

CaptainToonces
2014-Nov-04, 09:29 AM
It seems to me like there's an eruption desperately trying to happen underneath Bartharboonka, but there is so much rock and ice covering it that it's stalled.

Do we see any melt-water on top of the caldera, or is it still cold enough on top of it?

Squink
2014-Nov-04, 02:52 PM
Do we see any melt-water on top of the caldera, or is it still cold enough on top of it?

From the Scientific Advisory Board's Nov 3 report: (http://en.vedur.is/media/jar/Factsheet_Bardarbunga_20141103.pdf)

Energy of the geothermal areas in Bardarbunga is now few hundred megawatts and the melting of water is
estimated around 2 cubic meters per. second. Not knowing where the geothermal areas are, this is ambiguous. However the same report series has claimed that heat flux to the base of the ice is increasing.

dgavin
2014-Nov-06, 01:21 PM
Official subsidence measured yesterday at 44m. So it looks like I will have a better baseline to project out from going forward. It appears to be slowing down slightly, my projected rate would of had it at around 48m by now.


The subsidence of the Bįršarbunga caldera has reached 44 m which corresponds to 1.1-1.2 km³.

Additionally some geothermal features outside of the caldera have subsided 5-8m in the last 11 days.

dgavin
2014-Nov-06, 01:46 PM
Link to the graphs of GPS measurements of the caldera's subsidence. http://www.vedur.is/photos/volcanoes/barc_gps_all_is.png Based on that, I calculated a new rate of about .32 m/day. It had started at around .45m/day. The curve of slowing subsidence can be seen on the graph as well.

dgavin
2014-Nov-06, 02:07 PM
Going to make my first ever, amateurish volcanic predictions.

1. It should reach 50m subsidence about Nov 24/25th.
2. Subsidence will continue along the slowing curve, placing the end of it (and the eruption) out to about mid May 2015.
3. Total subsidence should reach 74m +-4m.
4. There should not be a catastrophic caldera collapse (Sorry to disappoint)

Squink
2014-Nov-07, 03:30 PM
This from today's SAB report:
The GPS station in the centre of Bardarbunga show that the subsidence of the caldera has decreased. Other measurements do though show that the volume of the subsidence increases with the same rate as it has done since these measurements started in September. This indicates that the flow of magma from Bardarbunga is not decreasing. So apparently there's now a larger area sinking more slowly, rather than just slower subsidence.

Squink
2014-Nov-21, 09:09 PM
Holuhraun eruption - fresh video (http://www.ruv.is/frett/holuhraun-eruption-fresh-video)
Aerial footage adds a good sense of scale to what the stationary camera show.
That's a large crevice the lava river is gushing out of.

Trebuchet
2014-Nov-21, 09:17 PM
Wow. Very impressive.

CaptainToonces
2014-Nov-26, 08:48 AM
And the seismic activity continues. Huge upheaval of magma is thwarted by giant mountain of ice, what will be the endgame?

Squink
2014-Nov-28, 04:10 PM
Fact sheet 28.11.2014 (http://en.vedur.is/media/jar/Factsheet_Bardarbunga_20141128.pdf):
Scientists flew over Bardarbunga on Wednesday, 26. November. According to data collected in the flight the total depression of the Bardarbunga caldera is 50 meters and the total volume of the depression about 1.4 cubic kilometre since the seismic activity started in mid-August.

Trebuchet
2014-Nov-28, 04:32 PM
Going to make my first ever, amateurish volcanic predictions.

1. It should reach 50m subsidence about Nov 24/25th.



Fact sheet 28.11.2014 (http://en.vedur.is/media/jar/Factsheet_Bardarbunga_20141128.pdf):

Not bad at all!

dgavin
2014-Dec-13, 03:02 AM
Thank you! We'll see if my other predictions pan out. Looks like I didn't quite get the slowing rate of subsidence down quite right, but I was close:) I probably should have used a parabolic curve formula for rate reduction instead of a sinual one.

CaptainToonces
2014-Dec-14, 06:13 AM
Thank you! We'll see if my other predictions pan out. Looks like I didn't quite get the slowing rate of subsidence down quite right, but I was close:) I probably should have used a parabolic curve formula for rate reduction instead of a sinual one.

or maybe a catenary curve. Or maybe it's all too complex to really predict! :)

dgavin
2015-Jan-11, 02:31 PM
As of Jan 6th.

The GPS station in Bardarbunga caldera show that the caldera continues to subside. The rate of the subsidence continues to slow down and is now around 13 cm per day.

Total Subsidence at 56m as of Dec 31st. It looks to be slowing down faster then I predicted.

Squink
2015-Jan-12, 03:18 PM
Quake frequency is down too.
Getting some mag 3+ quakes showing up further from the Caldera center now.
For example, on saturday, mag 3.6, 5 km deep and 11.7 km SE of Bįršarbunga.
Haven't seen spread in that direction before.

jj_0001
2015-Jan-14, 11:25 AM
Anyone tried to fit the deflation to an exponential of the k ( 1 - e^at) sort?

Squink
2015-Jan-26, 07:36 PM
Notes from surveillance flight with LHG to the eruption site, 21 JAN 2015 (http://en.vedur.is/media/jar/Notes-from-surveillance-flight-to-the-eruption-site.pdf) (PDF)

Observations from the previous surveillance flight held on 10 JAN had already indicated that the intensity of the eruption had decreased since early DEC 2014. Observations made on 21 JAN not only confirm this, but also indicate that the intensity of the eruption has decreased (markedly) further. The collective evidence is given hereComparison of photos of the lava channel on 10 and 21 january show a much decreased stream on the 20th.

Holuhraun Crater as Big as Iceland’s Tallest Church (http://icelandreview.com/news/2015/01/20/holuhraun-crater-big-icelands-tallest-church)
The crater which has formed at the Holuhraun eruption site in the northeastern highlands is now 80 meters (263 feet) tall, higher than the second-tallest building in Iceland and Iceland’s tallest church, Hallgrķmskirkja in Reykjavķk, which measures 74.5 meters. The crater is 100 meters wide and several hundred meters long.

Not so simple after all, Jan 28 (http://en.vedur.is/media/jar/Factsheet_Bardarbunga_20150127.pdf): (pdf)

Comprehensive cross-section measurements from air (on 30. December and 21. January) show however that the lava field has thickened substantially during these three weeks and that the volume of the lava field is now little less than 1.4 km3. The flow of magma, during this period, was just under 100 m3 per second. The intensity of the eruption is
there for slowly decreasing but hopefully it will be possible to measure the volume of the lava field again later this week, which will give new numbers on the flow of magma.


jj_0001: GPS broadcast from the caldera went down in december, and AFAIK, they haven't been able to get in there to fix the device yet. That leaves a hole in the data.

Squink
2015-Feb-11, 03:18 AM
Vatnajökull just went 10 hours between quakes (http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/) of mag >0.5. Things are really calming down these past couple weeks. Still magma coming out at vent (http://www.livefromiceland.is/webcams/bardarbunga-2/), but haven't seen big lava fountains for a while either.
Next day: They just added 3 mag ~1 quakes to that period. Probably took them a while to sort them out from windstorm produced noise. Still, quake activity is much below previous levels.

Squink
2015-Feb-20, 08:17 PM
Holuhraun Eruption in Final Days? (http://icelandreview.com/news/2015/02/20/holuhraun-eruption-final-days)
Volcanologist Haraldur Siguršsson predicted in October last year that the eruption in Holuhraun would end on March 4 and it appears his prediction may not be too far off the mark, visir.is reports.

There has been a significant reduction in the eruption in the last few days and it appears that the lava lake, which was being continuously filled with new lava, is closing. Quakes are way down, no visible smoke plume during clear daytime for the past week.

CaptainToonces
2015-Feb-25, 05:16 AM
Yep activity is down, but not gone altogether. I'm still pulling for another big show from this event. Looking at the eruption history in Iceland, it looks like most of the big ones tend to happen in the spring months, no?

Squink
2015-Feb-28, 04:22 PM
THE SCIENTIFIC ADVISORY BOARD OF THE ICELANDIC CIVIL PROTECTION (http://en.vedur.is/media/jar/Factsheet_Bardarbunga_20150228.pdf)
Date: 28.02.2015

The volcanic eruption in Holuhraun, which began on August 31st 2014, has come to an end.

dgavin
2015-Mar-01, 04:36 AM
Rate of Caldera subsidence down to just 5cm a day. Estimated total subsidence at 62m. I don't think it will reach my predicted 70m - 78m range. Also stopped 2.5 months before I predicted.

Squink
2015-Jun-11, 06:49 PM
Pretty good swarm along the Reykjanes ridge today (http://en.vedur.is/earthquakes-and-volcanism/earthquakes/reykjanesridge/) (to the west of Reykjavķk). Six or seven over mag 3 in a 6 hour time frame.
Holuhraun remains relatively quiet.

CaptainToonces
2015-Jun-12, 02:40 PM
Actually, the Bartharboonka system (including Holuhraun) is rumbling a bit these days. A mag 3 near the Bartharboonka caldera yesterday, and a light swarm of mag 1's continuing all through the area.

Squink
2015-Jul-01, 08:30 PM
Another big swarm at the Reykjanes ridge (http://en.vedur.is/earthquakes-and-volcanism/earthquakes/reykjanesridge/#view=table).
477 quakes in the past 48 hours. 35 over magnitude 3. Max was magnitude 5.0 at 3.5 km depth.
Iceland Review is on the story (http://icelandreview.com/news/2015/07/01/two-hundred-earthquakes-southwest-iceland).


Vatnajökull (http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/) (Holuhraun etc.) looks like it continues to cool down, with 25 quakes of up to max magnitude 2.