![yearly_activity[1]](https://wattsupwiththat.files.wordpress.com/2014/08/yearly_activity1.png?quality=75)
From the Icelandic Meteorological Office:
A summary of seismic activity, written Tuesday evening 19th August 2014 at 20:00
Around 1.000 small earthquakes were detected in the Bárðarbunga region from midnight (18/19) until Tuesday evening 19th August at 20:00. All of them were smaller than magnitude 3 and most were located in the cluster east of Bárðarbunga.
While the northern cluster close to Kistufell has calmed down significantly following the M4.5 earthquake on early Monday morning, event rates in the eastern cluster are still high. Similar to recent days, two pulses of comparably strong seismic activity have been measured between 04:00 and 08:00 this morning, as well as 16:00 and 18:30 in the afternoon. The cluster east of Bárðarbunga continued to slowly migrate northeastwards today. Events are still located at around 5-12 km depths, no signs of upwards migration has been seen so far.
Below is a summary map of all manually revised earthquakes since the onset of the swarm, which illustrates the migration of earthquake activity during the last days. Earthquakes in the map are colour coded by time, dark blue dots show the onset of the swarm on Saturday, orange dots Tuesday’s events until 19:00, light blue and yellow are the days in between. The time scale is days since the onset of the swarm.
Map by Gunnar B. Guðmundsson, Icelandic Meteorological Office.
via WUWT commenter “unmentionable”:
From the quotes below it sound like they’re crossing their fingers and toes that this thing stays underground and does not get any bigger. the longer the tremor goes on like this the worse its going to be if it pops under 2,000 ft of water ice.
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Magma flowing into Bárðarbunga caldera with great force – 20th August 2014
http://www.visir.is/magma-flowing-into-bardarbunga-caldera-with-great-force/article/2014140829931
Kristín Vogfjörð, seismologist and research director at the Icelandic Meteorological Office, says that the activity is very powerful. “This just keeps going on. This is many times more powerful than what’s been going on in recent years.” Kristín says that a large volume of magma is flowing under the caldera, heading northeast towards the Kverkfjöll mountain range. The magma is staying at a depth of 5-10 kilometers – there are no signs of it moving any closer to the surface. If asked if an eruption is due to happen in the next few days, Kristín responds: “Not necessarily. There’s nothing suggesting that it’s about to. But due to the size and scale of the activity there’s full reason to be vigilant and prepare for an eruption.”
Magma surge towards the surface would be very powerful – 20th August 2014
http://www.visir.is/magma-surge-towards-the-surface-would-be-very-powerful/article/2014140829927
Kristín Vogfjörð, research director at the Icelandic Meteorological Office, says that the current seismic activity at Bárðarbunga is many times more powerful than any on record for the site. “It’s very powerful,” she says. For comparison she notes that thousands of quakes have been measured at Bárðarbunga in the past week, but in the Gjálpar eruption in 1996 they were only a few hundred. … “While this is going on, it may never reach the surface. But we still need to keep an eye on it because the volume of magma is incredible,” she adds. …”There is no indication that it’s moving further up than that. But if it were to happen, it would happen very quickly,” Kristín states.
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Mag 2.4 at 1.2 km depth
15,0 km ESE Kistufelli at Mag 2.4, 10 minutes ago, at 1.2 km depth, with 90.02% quality
Where is the town of Akuyeri in relationship to Bardarbunga? I see that they had a 4.3 quake some 6 hours ago.
I have watched the daily USGS quake map for the last 3.5 years. I note that you don’t think much of lunar effects playing any part with what is happening with the magmatic influence, and I see your well reasoned explanation which makes sense. I have noticed over the years that earthquakes in general appear to be affected by the changing moon. There tends to be less quakes right around the max or min of the moon cycle. Although, some of the larger quakes seem to activate at these points, as if the influence could be from the peak of the change in direction of the lunar tide.
It’s at the base of the N-S trending long inlet on the central Northern coastline.
http://en.vedur.is/earthquakes-and-volcanism/earthquakes#view=map
The following is the only >3 quake that’s occurred in that area today (north of the town). I’d say the USGS initial was over estimated and reclassified
Friday 22.08.2014 01:26:29
LONG 66.223
LAT-18.226
DEPTH 11.4 km
MAG 3.3
QUALITY 99.0
The one more straw breaks the camels back theory, eh? I’ve heard that asserted for static magma chambers. The theory is that the tidal minimum leads to the peak compressive pressure rise in a closed chamber and if it is close to a tipping point it can trigger eruption at that point. Have a look at the harmonic tremor plot for Bardarbunga. Tides come in and out twice a day, and it does not. http://www.jonfr.com/volcano/?p=4736
In igneous there’s a plutonic intrusion feature called a layered intrusion, which forms when very large subterranean bodies of magma which don’t erupt, very slowly cool over tens of millions of years and progressively crystallize. As they do so different layers of crystals are laid down on the floor of the intrusion and different crystal types build up slowly until you get multiple horizontal layered stripes in the hard rock, recording a lack of mixing or stirring over millions of years, as they heterogeneously solidified. Compelling evidence magma tides are not a factor in stirring up magma or making it slosh around.
http://www.unalmed.edu.co/rrodriguez/geologia/ofiolitas/Lecture%206%20Layered%20basic%20intrusions.htm
Thanks! I looked at the EMSC map and they also show a 4.3 at 15:41 UTC. Also thanks for the great detailed information which you have presented here. I am not necessarily implying the ‘last straw’ thought, but more like a shift of direction influence.
or a stall point in influence
goldminor says:
August 22, 2014 at 5:02 pm
Thanks! I looked at the EMSC map and they also show a 4.3 at 15:41 UTC. Also thanks for the great detailed information which you have presented here. I am not necessarily implying the ‘last straw’ thought, but more like a shift of direction influence.
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I do see what you’re getting at and that is in fact the one more straw thesis. I remember seeing a trace of a short series of eruptions in Guatemala many years ago plotted against tidal phase and most of the eruptions either occurred on the lower half of the falling tide or close to its lowest point. The suggestion made was that in some rare structural geometries such an effect could emerge within a finely balanced system. So it’s not able to be ruled-out. But I doubt it is a valid correlation, for instance, the natural period of harmonic tremors in the Guatemala instance could also be on a 12 hour cycle, that just happened to be in rough phase with what the tide was doing during the eruption sequence, but otherwise unrelated.
But as a general effect on existing high intensity intrusion its untestable and powerfully overridden as just the mere turbulence within the material dwarfs any tiny secular lunar pull.
Re the quake, this is the official Iceland record and there’s only a 4.0 and a 4.7, both are near Bardarbunga:
http://en.vedur.is/earthquakes-and-volcanism/earthquakes#view=table
The EMSC map agrees, there was no mag 4.3 near Akuyeri, only a 3.3 and a smaller one. That area routinely has a sprinkling of quakes per week.
http://www.emsc-csem.org/
Funny, both the USGS and EMSC still show a 4.3 there.
My attempt at explaining was not well done. I am feeling a bit off key today. Although, I see where you think that I am stating this in reference to volcano activity. I should have stated that this is related to the daily earthquake count. The lowest daily counts are often around the full moon, and the dark of the moon. Then activity increases after each of those points.
Mag 2.1 at 21 km depth on the SW end of the Dyngjujökull fissure swarm.
That’s the largest deep one under the main fissure complex so far, a trend that began to become obvious yesterday. The magma is moving more force fully even that far down. That this part of the sub crust is about the most plastic, so if stress is rising fast enough there, even as the tension relief quakes are going deeper, then the rest of the plume is still applying tension to the base of the crust to wedge open the fissure conduit more. The only larger and deeper quake was a mag 2.2 that occurred yesterday under the Kverkfjöll caldera area. So a sprinkling of quakes are getting both deeper and larger down to ~24 km, and occurring over a wide area.
I now see what you are getting at if this is the one you’re referring to over at EMSC.
http://www.emsc-csem.org/Earthquake/earthquake.php?id=396369
It says: “127 km S of Akureyri” That’s just to the west of Bardarbunga, not near Akureyri at all.
It also says “Source parameters not yet reviewed by a seismologist”.
More like not updated yet for if it were valid it would have showed up in the Icelandic tabulation rather smartly, as they’re giving immediate attention to all the big ones.
So I checked the EMSC date and time stamp against the Icelandic list date and time and the only one that occurred during that minute was at:
Friday 22.08.2014 15:41:06 [i.e. only 2 seconds different]
64.622 -17.463
Depth 3.0 km
Mag 2.8
Quality 99.0
3.7 km SE of Bárðarbunga
That’s the same quake goldminor, EMSC and USGS are displaying inaccurate first returns, not the corrected data.
goldminor says:
August 22, 2014 at 10:34 pm
The lowest daily counts are often around the full moon, and the dark of the moon. Then activity increases after each of those points.
—
I’ve heard of that in earthquakes terms around 15 years ago on the usenet.geo newsgroups but could not take it seriously as the person pumping it was putting about all sorts of Art Bell stuff. I became prejudiced and did not look deeper and put it in the same mental place as moon-effects on magmas. But I can see how a fault could be ‘crept’ to a failure once near a failure. At least as a concept.
I see many geophysical things wrong with the general thesis of elastic storage in a crustal basement rock that’s chock full of discontinuities and highly dessicated polygonal crustal jointing, foliations and cavities, that are lined with mica, graphite and metals like molybdenum. These are all tremendous crystal-level structural lubricants that are typical of almost all fault surfaces, to some degree, but are common at the interface discontinuities as is copious liquid water. (the only thing missing seems to be a cake of soap and a banana peel).
It’s even worse in active regions as it is by far the most discontinuous and fractured crust, as a result of past quakes, yet is supposed to store huge strains. How is elastic strain supposed to accumulate in the crust, when it could not be more disjointed or more lubricated in fracture zones and major crustal decollements?
It’s like suggesting you can store massive elastic energy in a rubber band if you first cut it into ten or more pieces. Good luck with that. 🙂
So the mechanism is wrong, even though it appears to explain the observations, as well as the apparent stretching and relaxation reflex of the crust. But could not be more inconsistent with the medium itself, nor any less viable across a tectonic strain accumulation distance. It’s a total nonstarter, but it is the emperors new and old garments.
It ‘s wrong and that much I know, but alas, we play in the elastic-storage dominated paradigm’s sand box, so you have to hold your nose and participate in their stuff. 😀
I will keep your observation in mind.
Large rapid swarm almost the full height of the main fissure from Mag 2 to Mag 2.8 began about an hour ago and is ongoing.
http://baering.github.io/
Distinct rise in magnitude is visible in the bottom plot, now tapering
http://en.vedur.is/photos/jarisls_rit/140823_1155.png
Harmonic tremor shows sharp rise almost off the scale
http://www.jonfr.com/volcano/?p=4761
Unmentionable,
Can the seismologist make accurate predictions of the amount and extent of the liquid phase under bardarbunga from the S and P travel times? A liquid does have different seismic properties to the surrounding crust n’est pa?
23rd August 2014 14:10 – a small eruption under Dyngjujökull
· A small lava-eruption has been detected under the Dyngjujökull glacier.
· The Icelandic Coast Guard airplane TF-SIF is flying over the area with representatives from the Civil Protection and experts from the Icelandic Met Offic and the Institute of Earth Sciences. Data from the equipment on board is expected later today.
· Data from radars and webcameras are being received, showing no signs of changes at the surface.
· The estimate is that 150-400 meters of ice is above the area.
· The aviation color code for the Bárðarbunga volcano has been changed from orange to red.
· Just now (14:04), an earthquake, estimated magnitude 4.5
AleaJactaEst says:
August 23, 2014 at 6:53 am
Unmentionable,
Can the seismologist make accurate predictions of the amount and extent of the liquid phase under bardarbunga from the S and P travel times? A liquid does have different seismic properties to the surrounding crust n’est pa?
__
I have seen two wildly varying estimates in the past 24 hours and nothing official, perhaps the Iceland Met Office will define some numbers later today.
eruption has broken surface, 15:35 BST
http://www.ruv.is/frett/small-eruption-near-bardarbunga
Small fissure eruption, we’ll just have to wait and see if it grows into something bigger.
correction: the eruption is sub-glacial. The volcano status has been changed from orange to red
http://www.jonfr.com/volcano/?p=4761
Mag 4.5 in Caldera
http://baering.github.io/
AleaJactaEst, I replied but it’s stuck in moderation, sorry.
Mag 3.1 low down in the fissure complex surge – largest so far.
This is disturbing as the fissure is unzipping from below, forced open, and there a very large volume of magma is entering it.
Things have definitely evolved lower down in the mush.
http://volcanodiscovery.com/bardabunga-earthquakes.html
This was posted from a commenter at volcano cafe from one of the webcams:
?dl=0
It’s not ash. I suspect this is either degassing that’s raising dust, or else it could be electrical repulsion pushing dust aloft.
Either way, it is not ‘dust devils’ as was previously reported elsewhere, and the entire western side of the icesheet is now obscured by it.
I checked the weather and it is supposed to he 12 km/h at 1000 hPa from 240.
BBC are currently showing helicopter footage of smokey ash just beginning to emerge form the central ice sheet.
Just noticed a Mag 3.4 in middle of the fissure complex – the new largest so far.
Regarding the BBC footage, I’m not 100% confident they were not just showing the old file footage of the beginning of the Gjlap eruption, in 1996, they were talking about Bardarbunga as they showed it, but …