![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.
What was the time between the ground subsidence and the eruption observed previously?
Sorry, didn’t see your second post.
Jean Parisot says:
August 21, 2014 at 4:54 am
What was the time between the ground subsidence and the eruption observed previously?
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Volcanoes shift before they spew – 12 January 2014
GPS data from 2011 Icelandic eruption hint at new ways to forecast hazards.
” … “A GPS site can tell you not only that there’s unrest at a volcano, but that it’s about to erupt and then how high its plume will be,” says Sigrún Hreinsdóttir, a geophysicist at the University of Iceland in Reykjavik. … Seismic instruments can detect an impending eruption, because earthquakes usually come fast and furious right before such an event. But only the GPS data hint at the actual size of the eruption to come, Hreinsdóttir says. …”
http://www.nature.com/news/volcanoes-shift-before-they-spew-1.14498
1 hour 20 mins ago
21st Aug 2014 10:58:09
Depth 3.1 km
Mag 3.8
Quality 99.0
4.8 km NE of Bárðarbunga
mag 4 earthquakes now occurring Thusday morning. I’m no seismologist but to my knowledge, that suggests strengthening and magma moving upwarward in the caldera.
Very bad jujuj. Ireland and Scotland and Northern UK look out.
http://en.vedur.is/photos/jarisls_rit/140821_1425.png
mods- why is WordPress sending posts to the bit bucket?
[The cause (for the greatly increased number of “wait for moderator” delays) is uncertain. The “clause list” (phrases that trip the programmed logic) has not changed recently, but the search engine (Akimsmet) may have been modified back at the source. Be patient, we’ll get through it. .mod]
Joel O’Bryan says:
August 21, 2014 at 7:43 am
mag 4 earthquakes now occurring Thursday morning.
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This can happen if the magma is running out of room, and/or the ground can’t displace and extend fast enough to accommodate the rest of the magma which is trying still trying to rise.
There’s a deep column of relatively less dense buoyant material that has been moving upward in bulk for over 130 hours. It has inertia so it doesn’t want to stop just because there’s some trouble with the plumbing above. This will be sorted out, one way or another, by earthquakes and fractures, if secular molecular creep displacement can’t do it fast enough.
Complication: New hot magma is gassy and reactive and new magma often does not mix well with old magma, and there’s always old magma.
So the new stuff either gets blocked under the old stuff, or it intrudes through it, and mostly lays above it. What strong magmatic quakes do is shake them together and increase mixing and reaction. As they mix they react more and exsolve more gas which increases the pressure further, which makes for more quakes. Even as more material below does not want to stop from rising at the same speed as prior. Billions of tonnes of stuff moving up will take a lot of stopping.
eventually a mag 4+ jolt is bound to open cracks to the underside of the ice sheet. Steam makes Millions of liters of water rushing into a magma chamber????
Worst case:
blows the several cubic km off the top of that ice pack. A long 20km fissure opens up, 300meter high lava fountains. SO2 & HF laden gass, by the mega tonne pour out.
Time frame: < 96 hrs.
Agust Bjarnason, joelobryan and Unmentionable:
Sincere thanks for your comments, running commentary, and explanations. This is very helpful to people such as me who know nothing of such matters. Please continue your informative posts that I – and I am sure many others – am finding very helpful.
Richard
I seem to recall that a few years ago when we had the last major eruption on Iceland, there was mention of that particular volcano having historically been a precursor to the eruption of another, larger volcano. Does anyone else recall this?
LeeHarvey says:
August 21, 2014 at 9:17 am
I seem to recall that a few years ago when we had the last major eruption on Iceland, there was mention of that particular volcano having historically been a precursor to the eruption of another, larger volcano. Does anyone else recall this?
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You’re referring to the triggering of the Katla complex on the south coast by Eyjafjallajökull’s eruption. Katla has had periodic quakes under it for most of the time since then.
http://en.wikipedia.org/wiki/Katla_volcano
Seconded.
If it blows and think of flying in Europe keep an eye on the wind map
http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=0.00,54.00,1106
August 21st. Bárðarbunga Earthquakes larger than 1.5 over the last 48 hours.
http://oddurk.cartodb.com/viz/68c57ac6-2931-11e4-bfc4-0edbca4b5057/public_map
Someone with the data access should try a 2D plot of seismic activity and the tide schedule for the nearest port, Hofn.
See:
http://www.windfinder.com/tide/hornafjordur_airport_hofn
Tide and seismic data association for Bárðarbunga region looks interesting to me. If there is an + correlation it suggests next set of mag 4 quakes will occur around 2100-2300 UTC tonight. It’s almost 1800 UTC now (1100 PDT), so in about 3-4 more hours, maybe another set of mag 4 jolts.
Morgunblaðið 21.8.2014 | 15:31 GMT/UT
>>>A magnitude 4 quake in Bárðarbunga<<<
Intense earthquake activity continues at the Bárðarbunga volcano. Since midnight, over 900 earthquakes have been detected in Bárðarbunga. Today three earthquakes exceeding three in magnitude have occurred on the caldera rim of Bárðarbunga, the largest one was magnitude 4. These earthquakes were at depths around 2 – 5 km. They are interpreted as possible adjustments of the caldera due to changing magma pressure. They are not assumed to be the precursor to an imminent eruption, according to scientists at the Icelandic Met Office.
There are no signs that the seismicity is decreasing. Seismic and GPS measurements reveal a 25 km long dyke being formed in the crust under the Dyngjujökull glacier at 5 – 10 km depth. Interpretation of the latest data suggests that the dyke has widened slightly at its north-eastern end beneath Dyngjujökull. The dyke has not propagated to the north-east, nor has it progressed to shallower depth.
The ongoing monitoring and assessment effort is necessary in case a volcanic eruption occurs. Hazards in the event of an eruption are being assessed, including a glacial outburst flood and dispersal of volcanic ash. Additional seismic, GPS and hydrological stations have been installed in the Bárðarbunga region. Likewise, mobile radars capable of monitoring ash dispersal have been moved to the region.
There are no measurements to suggest that an eruption is imminent. Previous intrusion events in Iceland have lasted for several days or weeks, often not resulting in an eruption. However an eruption of Bárðarbunga cannot presently be excluded, hence the intense monitoring and preparation efforts.
http://www.mbl.is/frettir/innlent/2014/08/21/a_magnitude_4_quake_in_bardarbunga/
Agust Bjarnason says:
August 21, 2014 at 3:35 am
=================================================
I like the way that they use color on their chart. It allows for easy interpretation of the flow of events.
the 8 hour old seismic events scatter conservatively span approx 1/4 of a line of longitude (at 65N that’s about 11km) and goes from surface to 35km (http://baering.github.io/) If one was to conservatively say 1/4 of that is magma (I don’t know, what would one presume would be a ballpark guess?) that’s 40km3 of very angry molten rock just waiting for a reason to say hello.
If you look at the events scatter over the last 5 days, the volume doubles.
Interesting reading from:
ICELAND
2006 Geodynamics Field Trip
May 30 – June 8, 2006
Massachusetts Institute of Technology/
Woods Hole Oceanographic Institution
Joint Program in Oceanography
http://www.whoi.edu/cms/files/iceland-trip_25604.pdf
The Skaftár Fires
“A devastation was brought about by the 1783-84 Laki (i.e. Skaftáreldar) eruption on the
late 18th Century communities in Iceland. The resulting Haze Famine (i.e.
Móðuharðindin) is the worst environmental and social-economic disaster in Iceland’s
history, killing 50% of the countries cattle, 77% of the sheep and one fifth of the human
population. The Lakagígar lava flow is the largest lava flow formed on Earth in at least
the last 1000 years. The average discharge during the first 50 days of the eruption may
have been close to 2000 m3/s. The 565 km2 and 14 km3 lava flow formed two main
branches that we will cross, driving back to Reykjavík.” (B. Brandsdottir)
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The Laki volcano complex is about 75 Km southwest of the current seismic activity loci.
More interesting reading of what this Icelandic volcano complex is capable of, is here:
http://onlinelibrary.wiley.com/doi/10.1029/2001JD002042/abstract
Unmentionable says:
August 21, 2014 at 8:41 am
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Where you point out the continuing dilation of the area, is it possible that the dilation can reach a limit of extension, and then push back into the expanding magmatic forces?
The entire northern and northeastern areas around Bárðarbunga.
Here’s a Google Earth photo of Lake Viti about 40 km northeast of the current seismic activity. This lake could get washed away.
https://www.google.com/maps/place/Laki,+Vatnaj%C3%B6kull+National+Park,+Iceland/@65.047374,-16.727371,3a,75y,90t/data=!3m5!1e2!3m3!1s14138865!2e1!3e10!4m2!3m1!1s0x48d104ba78f4518d:0xc96945ee63bc0993
goldminor says:
August 21, 2014 at 11:54 am
Unmentionable says:
August 21, 2014 at 8:41 am
=======================================
Where you point out the continuing dilation of the area, is it possible that the dilation can reach a limit of extension, and then push back into the expanding magmatic forces?
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No, that won’t occur, the crust is tensional (being stretched) due to it being a rift triple-junction. It will remain distended with little closing even after the magma is gone, a dyke swarm in the mid and lower crust will wedge it open permanently and the upper part will remain open at lower static pressure and be a cavity for the next eruptive cycle.
This is how Iceland grew.
AleaJactaEst says:
August 21, 2014 at 11:22 am
(trim)”… that’s 40km3 of very angry molten rock just waiting for a reason to say hello.
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I wouldn’t mind seeing the guestimates by the Iceland Met office. They were clearly impressed by the numbers yesterday.
There’s an awful lot of scaremongering going on about #Bardarbunga. For *real* news, just follow @gislio & @subglacial #ashtag
http://www.twitter.com/subglacial
mag 4.7 jolt, depth 4.3 km, just 4 km south-east of Bárðarbunga 15 minutes ago.. This gal is getting angrier. If she doesn’t pop though in the next 48 hrs though the tidal forces are waning until they peak again next Wednesday-Thursday.
http://en.vedur.is/photos/jarvatj_rit/140822_0050.png