Bardarbunga and Askja Volcanoes in Iceland (Month 1)


 

Update, May 9, 2015: A few days ago, Jón Frímann (a blogger in Iceland) noted the presence of an earthquake swarm at Askja. He says:

There is nothing suggesting that current earthquake swarms are due to magma movements at shallow depths. This is rather hydrothermal activity changes in the volcano due the it being warmed up by new magma entering it and warming up groundwater inside the volcano. That has happened before in earlier eruptions and is documented, the time scale of such changes is not documented far as I know.

Askja volcano started for prepare for an eruption phase in 2010, so far nothing suggest that an eruption is imminent, but it remains a question if the push from Bárðarbunga volcano has changed anything in Askja volcano.

 
 

NOTE: STARTING MONDAY, THE 29TH, THERE WILL BE A NEW POST AND THIS ONE WILL BE ARCHIVED UNDER MONTH 1.

 

Update, September 28, 2014, 5:19 p.m. Pacific:

A spectacular video posted on YouTube on September 20th (h/t David Bressan):
 

Update, September 28, 2014, 2:08 p.m. Pacific: Aviation code: Not given for the 27th or today (I just noticed), but presumably still – Bardarbunga, orange. Askja, green. There are no updates on the University of Iceland’s Bardarbunga site since the 26th. Per the Iceland Met Office, things today at the volcano are similar to yesterday.
 


 
Update, September 27, 2014, 10:23 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.
 

 

Scientists say:

Seismic activity: Seismic activity continues at a similar rate at Bárðarbunga and the northern part of the dyke. For the last 24 hours, six events of M>=3 have occurred, the largest ones at northern Bárðarbunga yesterday afternoon M5.2 and at 02:00 this morning M5.1.

Plume and lava: Visibility in the eruption area is poor due to weather. The plume was observed again on webcam late this morning. Last field observations yesterday indicated that the lava was still flowing northwards, possibly also east according to thermal images but that has not been confirmed by the field team.

Displacements: The subsidence of the Bárðarbunga caldera continues with same rate as before. GPS measurements show continuing slow movements.

Water monitoring: No change was detected in water monitoring.

Forecast for gas dispersion: For the next few days many low pressure areas will pass Iceland. Wind direction will be changing quite frequently. In such conditions gas dispersion forecasting is difficult. The gas should move quite rapidly with the winds, and not accumulate in one specific area.

After the weekend, south and southeast winds are prevalent. The forecast for the weekend:

Saturday: Easterly or variable winds. Pollution mostly expected west of the eruption site.

Sunday: Westerly winds. Pollution mostly expected to southeast and later east of the eruption.

Update, September 26, 2014, 10:55 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

Scientists say that the eruption’s rate, seismicity, and SO2 pollution are the same, as is the rate of caldera subsidence. The University of Iceland has analyzed the eruption plume and found it to be 80-85% H2O, about 10% SO2, and only about 5% CO2.

They took a gorgeous picture last night:
 

Also, the lava has crossed a nearby road.  (Image source, Photo from 25. September at 23:10. Morten S. Riishuus)

Also, the lava has crossed a nearby road. (Institute of Earth Sciences, Morten S. Riishuus)

 


 

Update, September 25, 2014, 4:48 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.
Wow!

 


 

Update, September 25, 2014, 4 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Per the geologist on duty:

25 September 2014 19:00 – from geoscientist on duty

Seismic activity around Bárðarbunga and the dyke intrusion has been persistent today and at similar rates as in recent days. About 40 earthquakes have been manually located in the northern part of the dyke intrusion and about 35 on the caldera rim of Bárðarbunga. Although the vast majority of events around the caldera occur on the northern rim, the ongoing occurrence of M>5 events on the southern rim, like this morning at 05:00, evidences still significant release of seismic moment in this area. It can not be concluded that activity on the southern rim is declining based only on the low number of events. The strongest earthquake in the dyke was M2.3 at 09:55. Six earthquakes on the caldera rim exceeded magnitude 3; the strongest of them were M4.2 at 04:25 (northern rim), M5.2 at 05:00 (south-eastern rim), M4.4 at 05:16 (northern rim) and M5.0 at 16:35 (northern rim).

Update, September 25, 2014, 11:03 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

Per scientists, both the eruption and the subsidence of the caldera continue at the same rates. SO2 pollution is still severe in some places, and:
 

 


 

Update, September 24, 2014, 3:33 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Ben Edwards tweets a comparison between this eruption and Laki’s (as well as the 2013 eruption of Russia’s Tolbachik) and notes this Bardarbunga eruption is “still in small to medium range”:
 

 

 


Update, September 24, 2014, 11:08 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Scientists say that the caldera has subsided a little over 90 feet since unrest began.
 

 


Update, September 23, 2014, 1:33 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

It sounds, per the University of Iceland and Iceland Met Office websites, that eruption events continue at the same rate. The volume of subsidence at Bardarbunga caldera is a little over half a cubic kilometer.
 

 


 

Update, September 22, 2014, 4:59 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

Satellite imagery shows two lava streams from the eruption site now.
 

NASA

NASA

VAST did another run today, per their website. Here is the sulfur dioxide forecast:
 

Volcanic Ash Strategic Initiative Team (VAST)

Volcanic Ash Strategic Initiative Team (VAST)


 


 

Update, September 22, 2014, 10:47 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.
 

 

Per scientists this morning:

The subsidence of the Bardarbunga caldera continues with same rate as before.

  • Big earthquakes are still detected in the Bardarbunga caldera. Since noon yesterday there have been 9 earthquakes bigger the M3,0. The biggest one was measured M5,5 at 10:51 yesterday morning making it the second biggest earthquake since this wave of seismic activity started on August 16. Smaller earthquakes were detected in north part of the dyke and around the eruption site.
  • Earthquakes up to M4 have been measured under the north-north-west mountain side of Bardarbunga.
  • No change was detected in water monitoring that cannot be explained with changing weather.

SO2 continues to be a problem in some parts of the island. The same three eruption scenarios are proposed, with others not ruled out.

The University of Iceland reports in a tweet that the lava field is 14 meters thick on average. It takes up roughly 38 km2 so the total volume erupted so far is about 0.5 km3. The average effusion rate is about 290 m3/s.

Of note, a VEI 0 eruption volume is 1 km3.

 


 

Update, September 21, 2014, 2:43 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.
 

 
Per scientists this morning:

The volcanic eruption in Holuhraun continues with similar rate as last few days. The eruption does not seem to be declining. The lava production continues with the same strength. The lava flow is now around the centre of the lava field, which is now around 37 square kilometres.

Scientists in the filed estimate that around 90% of the SO2 gas coming from the eruption originates in the active craters and only 10% from the lava field. Scientists have also become aware of dead birds around the eruptions site.

The subsidence of the Bardarbunga caldera continues with same rate as before.

Big earthquakes are still detected in the Bardarbunga caldera. Since noon yesterday there have been 18 earthquakes bigger the M3,0. The biggest one was measured M5,0 at 17:11 yesterday afternoon. Smaller earthquakes were detected in north part of the dyke and around the eruption site.

No change was detected in water monitoring that cannot be explained with changing weather.

Air quality:

  • SO2 pollution has been reported around Iceland over the weekend but no serious incident has been reported. People are encouraged to familiarise oneself with instructions from health authorities. Further instructions can be found below.
  • A prediction from the Icelandic Met Office: Pollution from the eruption is mostly expected north of the eruption today, but can affect a larger area, especially early on before the southerly wind increases. A map showing the gas forecast can be found on the web page of the Icelandic Met Office http://www.vedur.is/vedur/spar/textaspar/oskufok/

Three scenarios are considered most likely:

  • The eruption on Holuhraun declines gradually and subsidence of the Bardarbunga caldera stops.
  • 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 Dyngjujokull, resulting in a jokulhlaup and an ash-producing eruption. It is also possible that eruptive fissures could develop in another location under the glacier.
  • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jokulhlaup, accompanied by ashfall.

Other scenarios cannot be excluded.

Update, September 20, 2014, 10:46 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.
 

 
Per the University of Iceland and Icelandic Met Office English-language update pages, the eruption and caldera collapse rates are about the same. The UI people do note:

  • Seismic activity has been rather intensive over the last 24 hours. The biggest was M5,3 at 14:21 yesterday and another one was measured M4,7 at 06:44 this morning. In total 10 earthquakes larger then M3,0 were detected in Bardarbunga since our last meeting.
  • Smaller earthquakes were detected in Dyngjujokull glacier and in north part of the dyke.
  • GPS monitoring continue to show irregularity in in the crustal movements over the last few days. This sign could indicate that the magma movement under Bardarbunga is changing.
  • No change was detected in water monitoring.

 


 
Update, September 19, 2014, 3:15 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

Rather grim, but that is only one of the three main scenarios possible, per scientists currently (noted below).

No dramatic changes noted from this morning. Scientists did note today that chemical analysis has shown the source of the lava being erupted is more than 10 km below the surface.
 


 

 

Update, September 19, 2014, 10:43 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Things continue about the same, though an afternoon wind shift is now sending SO2 over eastern Iceland. If the VAST forecast of the 17th verifies, this pollution will also affect parts of Greenland and, this weekend, Scandinavia. The same three scenarios are in effect, though others aren’t excluded.
 


 

Update, September 18, 2014, 1:34 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

The eruption continues at the same rate. Some of the scoria cones have been given names:
 

Icellandic Meteorological Office

Per the Icelandic Meteorological Office: “Eruption site in Holuhraun 18.09.2014 at 09:30. Names make the registration of observations easier as well as the communication between scientist in the field. Photo: Ármann Höskuldsson.”

Gas pollution is expected in some northern parts of the country. Per the Icelandic Met Office:

Measurements of SO2 emission rates with permanently installed scanning DOAS instruments preliminarily indicate 200-600 kg/s SO2 over the last week of the eruption.

Relating SO2 to other gases measured by FTIR preliminarily indicates 250-700 kg/s CO2, 2-6 kg/s HCl, 3-8 kg/s HF, and <1 kg/s CO.

These emission rates may be underdetections due to measurement conditions. Experiments will be made this week to help us constrain the measurement bias and uncertainty, and these emission rates will likely change. These values are not to be used for further research as they are preliminary and all rights to the data belong to the scientists who are acquiring and interpreting the data.

The participating institutions include: Icelandic Meteorological Office, Chalmers University of Technology, Istituto Nazionale di Geofisica e Vulcanologia, Düsseldorf University of Applied Sciences, University of Palermo, University of Cambridge, and British Geological Survey.

Here is an interactive SO2 map I found just now on Twitter:

Per the geologist on duty this evening, “Nearly 150 earthquakes have been recorded since midnight. About 45 of them occurred in Bárðarbunga, the largest a magnitude 5.3 at the northern rim of Bárðarbunga caldera at 14:22. The GPS station on Bárðarbunga showed a drop of 15 – 20 cm at the time of the earthquake.”

Scientists said earlier today:

Three scenarios are considered most likely:

  • The eruption on Holuhraun declines gradually and subsidence of the Bardarbunga caldera stops.
  • 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 Dyngjujokull, resulting in a jokulhlaup and an ash-producing eruption. It is also possible that eruptive fissures could develop in another location under the glacier.
  • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jokulhlaup, accompanied by ashfall.

Other scenarios cannot be excluded.

Update, September 17, 2014, 11 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

Vog – the least photogenic volcanic hazard:

Scientists say that easterly winds will blow the SO2 to the west and southwest today. The current VAST forecast shows that parts of Greenland and Scandinavia may also get some of it in a couple of days.

The scientists describe seismicity as “rather intensive over the last 24 hours. Yesterday 7 earthquakes larger then M3,0 were detected in Bardarbunga. The biggest were M5,4 and M4,8 last night. Smaller earthquakes were detected in Dyngjujokull glacier and in north part of the dyke.”

Irregular GPS measurements are thought to be indications of some sort of a change in magma movement. There’s no sign of a decrease in eruptive activity and the lava field continues to grow. The caldera continues to subside at the rate of about 50 cm (20 inches) a day.
 


Update, September 16, 2014, 3:02 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

The news is about the same. Bardarbunga’s caldera subsided about 50 cm in the last 24 hours. The geoscientist in charge notes at 7 p.m. local time: “Some of the GPS stations have shown a change in direction since yesterday. Scientists will take a closer look on that change.”

Update, September 15, 2014, 11:23 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

Bad conditions (PDF) have kept scientists away from the eruption site, though not all the time:
 

 

The lava is not moving quickly enough to cross the river and is spreading around. Seismic and eruptive activities have continued at about the same intensity. The slow collapse of Bardarbunga caldera continues at about the same rate. Air pollution from SO2 is still a significant problem. The VAST forecast shows Scandinavia getting a break until the 17th.

The scenarios remain the same:

Three scenarios are considered most likely:

  • Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.
  • 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.
  • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jökulhlaup, accompanied by ashfall.

Other scenarios cannot be excluded.

Update, September 14, 2014, 3:59 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Scientists say that the eruption continues at the same intensity. Air quality continues to be bad in parts of eastern Iceland. However, the VAST forecast currently indicates that Scandinavia will get a break until the 17th or 18th.

The caldera continues to slowly subside.
 

In a tweet about 13 hours ago, the University of Iceland said only the central part of fissure 1 is currently active.

 


 

 

Update, September 12, 2014, 5:11 p.m. 13, 2014: Aviation code: Bardarbunga, orange. Askja, green.

Last night at 10 p.m., the highest values of SO2 ever recorded in Iceland were noted at Reyðarfjörður. High levels were noted in other places, too. Today authorities say:

  • Air quality in urban areas in the East of Iceland:
    – Forecasts indicate that high concentrations of sulphuric gases may be expected in the northern part of the Eastern fjords, Fljótsdalur, Hérað, Jökuldalur, and on Langanes. Forecast indicates that concentration may become higher later today. The Environment Agency will set up new monitoring stations in Akureyri and in South Iceland. Geographical conditions must be considered when estimating air quality.
  • Instructions:
    – People who feel discomfort are advised to stay indoors, close the windows, turn up the heat and turn off air conditioning. Use periods of good air quality to ventilate the house. Measurements of air quality can be found on a map from the Environment Agency. The Icelandic Met Office issues text forecasts and warnings in header if conditions change to the worse.
    – Some advise from The Environment Agency can be found on their web-site.
    – The Icelandic Met Office will read forecasts for sulphuric gases along with weather news on the national radio and TV.
    – The Environment Agency is working on getting more measuring equipment to better monitor the gases coming from the volcanic eruption.
  • Air quality at the eruption site:
    – Gas emissions at the eruption site remain high. As local gas concentrations at the site can be life threatening, people at the eruption site should wear gas masks and gas meters. At the eruption site, local wind anomalies can occur due to thermal convection from the hot lava. This makes the conditions on site extremely dangerous as winds can change suddenly and unpredictably. Scientists in the field carry gas meters for their security.
    – Degassing from the volcanic eruption is now estimated to be up to 750 kg/sec.

That last note is interesting. As an amateur I can’t say much about it that’s informed or intelligent, other than that every volcano is unique. There is no “standard” degassing rate. Here is a highly-cited paper (PDF) on excess degassing, which apparently can happen when an eruption degasses more than the amount of volatiles in the magma. It may not be relevant since first samples of the magma were shown to have high sulfur content (see below – I forget which day it was).

I doubt that anyone knows what the degassing rate was at the big Laki eruption.

Otherwise, eruptive activity and the caldera’s slow collapse are going on at the same rate.

Update, September 12, 2014, 5:11 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Uh-oh. Read the story here. Nice graphics of the three scenarios mentioned earlier today (see below).

Update, September 12, 2014, 12:38 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green. Per Jon Frimann, there are at least two lava lakes now, and they are at fissure 1. The caldera is reportedly dropping at a rate of 80 cm (a little over 2-1/2 feet) per day and cracks are appearing in the overlying glacier.

Update, September 12, 2014, 11:48 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, green.

The fissure 1 eruption continues. Seismicity remains similar to yesterday’s levels. Jon Frimann, in Iceland, says that local news is reporting the presence of a lava lake (small) in “one of the south crater.” It is said this crater isn’t erupting, so I’m interpreting that to mean fissure 2.

For the first time, I’m starting to realize (though others, familiar with Icelandic volcanoes probably have long been aware) that this eruption has a slight (and scary) resemblance to the Laki eruption.

If you’re not familiar with it, or think that only explosive eruptions are deadly, the gases that were unleashed during that 1783-84 fissure eruption near Grimsvotn – and also near Bardarbunga – were deadly, particularly sulfur dioxide and fluorine. I haven’t seen fluorine mentioned yet in association with the ongoing eruption at Bardarbunga. In the post linked above, Jon Frimann says:

The area around the eruption site is toxic. Due to ever changing wind in the area the risk of getting SO2, CO, CO2 and other toxic gases over one self is always present.

As for urban areas in eastern Iceland, earlier today, scientists met with representatives of the Icelandic civil protection, environmental, and public health agencies. They report:

  • Forecasts indicate that high concentrations of sulphuric gases may be expected in the northern part of the Eastern fjords, Fljótsdalur, Hérað, Jökuldalur, and Vopnafjörður. Forecast indicates that concentration may become highest in Hérað later today. High concentrations could occur in other areas as well. The Environment Agency will set up new monitoring stations in Akureyri and in South Iceland today. Geographical conditions must be considered when estimating air quality. People who feel discomfort are advised to stay indoors, close the windows and turn off air conditioning. Measurements of air quality can be found on the webpage loftgaedi.is. The Meteorological Office issues forecast on its web-page and warnings if conditions change to the worse.
  • Instructions from the office of the Chief Epidemiologist and The Environment Agency can be found on their web-sites.

No links are given to those websites, and they’re probably in Icelandic, so I haven’t tried to find them.

Parts of Scandinavia are going to be affected by SO2over the next couple of days, too, per the European Space Agency’s Volcanic Ash Strategic Initiative Team.

A new GPS station has been placed at the Bardarbunga caldera, which continues to subside. It’s believed slightly more magma is entering the dyke than is being erupted.

While they don’t rule out other scenarios, these three are considered possible currently, per the scientists:

  • Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.
  • 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.
  • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jökulhlaup, accompanied by ashfall.

Update, September 11, 2014, 12:24 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, changed to green.

The fissure 1 eruption continues. Earthquake activity at the northern end of the dyke has lessened, and I’m thinking that may be why they put Askja back to green (in addition to apparently low levels of seismicity – it hasn’t been mentioned at Askja in recent bulletins). Scenarios listed:

  • Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.
  • 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.
  • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jökulhlaup.

Other scenarios aren’t excluded. Air quality in parts of Eastern Iceland is still bad.

Update, September 10, 2014, 12:17 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, yellow.

Apparently the concerns expressed yesterday about caldera subsidence affected the scenarios. Three are currently posted:

Three scenarios are still considered most likely:

  • Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.
  • 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.
  • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jökulhlaup.

Other scenarios cannot be excluded. Factsheet pdf

Air quality is still bad in Eastern Iceland. The fissure 1 eruption site is dangerous because of sudden wind shifts, but scientists are still there off and on when possible. The eruption continues at the same rate as yesterday. Lava is flowing in the Jökulsá á Fjöllum riverbed, but there is only steam, no explosions.

Update, September 9, 2014, 4:08 p.m. Pacific: The director of Iceland’s Civil Protection Agency says he is “gravely concerned” about the subsidence of Bardarbunga’s caldera. Dave McGarvie, of the UK’s Open University, has recently written a blog post, “So what if there was an eruption at the Bardarbunga caldera…?

Update, September 9, 2014, 10:30 a.m. Pacific: As of right now, per the IMO website, things are pretty much the same as yesterday.

Update, September 8, 2014, 2:01 p.m. Pacific: Current update on website (emphasis added):

8th September 2014 19:20 – from geoscientist on duty

The earthquake activity today continues at the northern part of the dyke intrusion. The largest earthquake in the dyke since the end of August occurred at 16:27 today with magnitude 4.5. The largest earthquakes located today at the caldera rim:
kl. 06:15, M 4,8
kl. 07:20 M 4, 6
kl. 14:48, M 5,0
kl. 17:53, M 4,3
An earthquake swarm is taking place north of Herðubreið. About 80 earthquakes have been recorded today, all below magnitude 2. Swarms in this area are not uncommon. Due to high concentration of SO2, scientists are leaving the area.

High-sulfur-content magma or different local weather? This may have something to do with it (sorry about the ads, but just shut off the sound and wait – it’s worth it). That is…a whirlwind of hot SO2? And we’re still on Earth? Wow!

“We haven’t seen anything like this before,” said Fred Prata, chief technology officer at Nicarnica Aviation in Kjeller, Norway, the inventor of the infrared camera used for the images. “I was quite surprised to see it.”

Also, subsidence – possible slow caldera collapse – continues at the Bardarbunga caldera.

Update, September 8, 11:08 a.m. Pacific: Aviation code: Bardarbunga, orange. Askja, yellow. Per the scientists’ report so far today, everything remains about the same. Seismicity is markedly lower, and there is no visible activity at fissure 2. Gas and steam are escaping from the fissure there. Air pollution from sulfur dioxide is a problem in eastern Iceland. When winds suddenly changed direction yesterday, gases made a scientist sick. Just from going through NASA’s sulfur dioxide monitoring site from an amateur viewpoint, it looks as though the sulfur dioxide plume was worst on September 5. Perhaps it has been at upper atmospheric levels and then got mixed down closer to the surface yesterday.

The same four eruption scenarios are possible, though others aren’t ruled out.

Update, September 7, 1:30 p.m. Pacific: Aviation code: Bardarbunga, orange. Askja, yellow. Scientists say eruptive activity was the same, with fissure 1 more active, until this afternoon when activity stopped at the new fissure. Magma flow is between 100 and 200 m3/s. Moving at about 1 km/day, the lava has reached a river with resulting steam but no explosions. Lava area yesterday afternoon measured around 16 km2. Seismicity is about the same, with two quakes greater than M5 at the caldera.

subsidence

Update, September 6, 2014, 10:49 a.m. Pacific: Aviation code: Bardarbunga, Orange. Askja, Yellow.

An overflight has shown that the Vatnajokull ice surface over Bardarbuna Crater has subsided 15 meters, consistent with subsidence of the crater floor. Scientists say, “Subsidence of this order has not been observed in Iceland since measurements of crustal movements started around the middle of last century.” There are no signs of eruption in the crater. Since the volume corresponds roughly with the amount of lava already erupted, they say, “The most probable explanation is that this subsidence is related to the recent high seismic activity and subsurface magma flow to the northeast.”

Two small but growing depressions noted in the Dyngujokull lobe of Vatnajokull are thought to be “signs of small and short subglacial eruptions.”

Two eruptive fissures are still active, though seismic activity has decreased and deformation is small. “The lava now extends 10 km ENE and has just under one km to reach Jökulsá á Fjöllum river.”

The following four scenarios are possible, though others can’t be excluded:

  • The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.
  • The dyke could reach the Earth’s surface at different locations outside the glacier. Lava flow and/or explosive activity cannot be excluded.
  • The intrusion could again reach the surface under the glacier and possibly lead to a significant eruption. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
  • An eruption in Bárðarbunga. The eruption could cause an outburst flood and possibly an explosive, ash-producing activity. In the event of a subglacial eruption, it is most likely that flooding would affect Jökulsá á Fjöllum. However it is not possible to exclude the following flood paths: Skjálfandafljót, Kaldakvísl, Skaftá and Grímsvötn.

Update, September 5, 2:50 p.m. Pacific: A new map shows the extent of the lava flow from fissure 1. The orange triangle to the south marks the new eruption site.
 

IMO/University of Iceland

IMO/University of Iceland

Update, September 5, 10:30 a.m.: Aviation code, Bardarbunga: Orange, in spite of new eruption. Askja: Yellow.

Two new fissures open up south of the eruption site and about two km away from Dyngjujokull. The new fountains are much smaller. Steam and gas rise from the ground in a line southeastward of the new site. Eruption is still going strong at the first fissure eruption, with the plume rising to about 15,000 feet. Seismicity is similar to yesterday’s, but hardly any deformation is noted.

Source.  (Icelandic)

Source. (Icelandic)

Update, September 4, 10:48 a.m. Pacific: Aviation code, Bardarbunga: Orange. Askja: Yellow. Fissure eruption continues, showing no signs of declining. The lava field is now about 10.8 sq km. A M4.8 quake and three other quakes over M4 occurred overnight in the northern part of Bardarbunga, but the number of seismic events is much lower. Most seismically active zones besides the eruption site are at the northern end of the dyke and under the Dyngjujokull lobe of the Vatnajokull glacier. No meltwater floods have been detected.

Around noontime, scientists report, among other things:
 

  • The low frequency tremor seen yesterday disappeared last night but started again this morning, however minor compared to yesterday. The source of the tremor is not certain, however, possible explanation could be magma-water interaction although this interpretation has currently not been confirmed by other observations.
  • The GPS time series indicate slower rate of deformation in the last 24 hours. The current deformation pattern north of Vatnajökull still suggests volume increase in the dike. No significant signs of deformation are observed around Bárðarbunga.
  • Four scenarios are likely:

    1. The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.

    2. The dike could reach the Earth’s surface causing another eruption, possibly on a new fissure. Lava flow and (or) explosive activity cannot be excluded.

    3. The intrusion reaches the surface and another eruption occurs where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.

    4. An eruption in Bárðarbunga. The eruption could cause an outburst flood and possibly an explosive, ash-producing activity. In the event of a subglacial eruption, it is most likely that flooding would affect Jökulsá á Fjöllum. However it is not possible to exclude the following flood paths: Skjálfandafljót, Kaldakvísl, Skaftá and Grímsvötn.

  • Other scenarios cannot be excluded.

Update, September 3, 2014, at 5:08 p.m. Pacific: No change on the IMO website. I just came across this tweet from earlier in the day:

Cool!

Update, September 3, 2014, at 1:39 p.m. Pacific: Aviation code, Bardarbunga: Orange. At Askja: Yellow. Fissure eruption continues.

Seismic activity remains at yesterday’s lower rate until a little after 3 a.m. when a M5.5 quake strikes the northern part of Bardarbunga. The geologists on duty at 6:24 a.m. says:

After that there was increase in activity both in the area under the northern part of Dyngjujökull, south of the current eruption site as well as in Herðubreiðartögl.

Scientists meet in the morning. The report that seismicity is occurring mostly beneath the northern edge of the Dyngjujokull lobe of Vatnajokull glacier. GPS measurements show that more magma is entering the dyke than is being erupted. They also say:

  • Recent radar images show a 0.5 – 1 km wide depression that has formed both in front of and beneath Dyngjujökull. Signs of the depression extend about 2 km into the ice margin. The increasing thickness of the glacier decreases the visual extent of fracturing associated with the depression, so it is likely that the area extends further beneath Dyngjujökull.
  • In light of GPS, radar and seismic results, it is possible that the ongoing eruption could progress southward under Dyngjujökull. This would lead to immediate flooding hazards on the floodplain in front of Dyngjujökull. Consequently, risk assessments for scientists working in the area will be reviewed.
  • At 08:00 UTC today the total area of the lava flow was estimated at 7.2 km2.
     
    Draft map of lava flow as of September 3.  Iceland Meteorological Office/University of Iceland

    Draft map of lava flow as of September 3. Iceland Meteorological Office/University of Iceland

  • Four scenarios are likely:
  • The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.
  • The dyke could reach the Earth’s surface causing another eruption, possibly on a new fissure. Lava flow and (or) explosive activity cannot be excluded.
  • The intrusion reaches the surface and another eruption occurs where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
  • An eruption in Bárðarbunga. The eruption could cause an outburst flood and possibly an explosive, ash-producing activity. In the event of a subglacial eruption, it is most likely that flooding would affect Jökulsá á Fjöllum. However it is not possible to exclude the following flood paths: Skjálfandafljót, Kaldakvísl, Skaftá and Grímsvötn.
  • Other scenarios cannot be excluded.

At 7 p.m., the geologist on duty says:

The origin of the increased tremor signal since this morning is still unclear and data is still analysed. However there are no signs of a subglacial eruption under Dyngjujökull. No obvious changes such as increased water flow or cauldrons on the glacier surface were observed from scientists onboard TF-SIF this afternoon. Water meters in Jökulsá á Fjöllum do not show any unusual changes in discharge and electric conductivity. The low frequent tremor signal is still continuing, its strength is variable.

Update, September 2, 2014, at 11:29 a.m. Pacific: Aviation code at Bardarbunga: Orange. At Askja: Yellow. Scientists report that seismicity and ground deformation have decreased noticeably in the last 24 hours, leading them to believe that magma inflow and outflow have equalized. Compared to the previous day, there is more SO2 in the plume. Again they say:

It remains unclear how the situation will develop. Four scenarios are still considered most likely:

  1. The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.
  2. The dike could reach the Earth’s surface causing another eruption, possibly on a new fissure. Lava flow and (or) explosive activity cannot be excluded.
  3. The intrusion reaches the surface and another eruption occurs where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
  4. An eruption in Bárðarbunga. The eruption could cause an outburst flood and possibly an explosive, ash-producing activity. In the event of a subglacial eruption, it is most likely that flooding would affect Jökulsá á Fjöllum. However it is not possible to exclude the following flood paths: Skjálfandafljót, Kaldakvísl, Skaftá and Grímsvötn
  5. .

Other scenarios cannot be excluded.

Update, September 1, 2014: (This is actually done on the 2nd of September due to yesterday’s holiday.) Aviation code at Bardarbunga: Orange. At Askja: Yellow.
 

Plume from fissure eruption, with tan-colored dust storm behind it.  Source (PDF)

Plume from fissure eruption, with tan-colored dust storm (not volcanic ash) behind it. Source (PDF)

Over 700 earthquakes are detected, mostly in the dyke, although more than 140 of them are centered northeast of Askja and a few are located at Askja. Two strong earthquakes, M5 or greater, occur at the northern rim of Bardarbunga Crater.

Scientists conduct an almost three-hour overflight:

Main conclusions:

  • The fissure is 1,5 km long. Continuous eruption takes place on a 600-800 m long central section. A single crater has been active at its southern end, but little or no lava extrudes from it now. Lava plumes rise to a height of a few tens of meters where the activity is greatest, centrally on the fissure.
  • The lava stretches 3,5 km ANA from the center of the fissure. It is max 1,6 km wide but narrower further from the craters. The edge of the lava is a tongue 500 m wide. A continuous lava stream flows along the center of the lava field, almost to the edge. The edges are glowing. Apparently, non of the tributaries of river Jökulsá á Fjöllum touches the lava edge.
  • The area of the lava is now 4 km2. At 16:00, a rough estimate gives 20-30 million cubic meters of lava. Which means that 5-10 million cubic meters have been added in 18-19 hours. Therefore, average flow is of the order of degree 100 m3/s.
  • Two small cauldrons in Dyngjujökull [glacier], aligned in the direction of the fissure, seemed unchanged since Friday 29 August.
  • Radar revealed no changes in Bárðarbunga nor in the depressions to the southeast of it.

Earlier in the day scientists meet. The plume has much SO2 and people should wear protection near it. They believe the dyke has not extended any further, although it remains fully pressurized. They say:

It remains unclear how the situation will develop. Four scenarios are still considered most likely:

  1. The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.
  2. The dike could reach the Earth’s surface causing another eruption, possibly on a new fissure. Lava flow and (or) explosive activity cannot be excluded.
  3. The intrusion reaches the surface and another eruption occurs where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
  4. An eruption in Bárðarbunga. The eruption could cause an outburst flood and possibly an explosive, ash-producing activity. In the event of a subglacial eruption, it is most likely that flooding would affect Jökulsá á Fjöllum. However it is not possible to exclude the following flood paths: Skjálfandafljót, Kaldakvísl, Skaftá and Grímsvötn.

Other scenarios cannot be excluded.

Update, August 31, 2014: Here is a lovely image of eruption at night, taken through one of the webcams.
 

 
I’ve seen no more news thus far this evening. Because of the Labor Day holiday, I won’t be on the Net tomorrow. Best bets for updates are the Icelandic Met Office and Dr. Klemetti’s “Eruptions” blog. Cristobal will have blown through – maybe there will be some good overflight video available tomorrow.

Right now, I’m curious if the scientists are still considering an eruption at the caldera as a scenario – they were on the 30th. With attention focused on the fissure eruption, there was no news about possible jokulhaups (glacial outburst flooding). Will wait and see how things unfold.

Update, August 31, 1:17 p.m. Pacific: Aviation code, Bardarbunga: Orange, after briefly being raised to red with onset of eruption – no ash detected. Aviation code, Askja: Yellow. A fissure eruption in the same as the one on the 29th occurs while severe weather from former Hurricane Cristobal pummels the area.

 


Video by Benedikt G. Ófeigsson via Icelandic Meteorological Office. Wind noise compliments of ex-Cristobal.

Little seismic activity noted at Askja. IMO and the University of Iceland issue a status report (PDF).

Note: Erik Klemetti says that analysis of samples from the August 29 eruption showed high amounts of sulfur in the lava. If it’s in the lava, it’s not degassing, one would think, but here is a NASA link to Iceland daily SO2 maps. I will put it down at the bottom, too.

Earlier in the day, scientists met:

Conclusions of the Scientific Advisory Board of the Icelandic Civil Protection:

A lava eruption started in Holuhraun shortly after 04 AM, on the same volcanic fissure, which erupted earlier this week. The fissure is estimated to be 1,5 km long. It was detected on Míla´s web-camera at 05:51 AM. Fewer earthquakes seem to follow the event than in the previous eruption, but more lava is being extruded.

At 07 AM the lava flow was around 1 km wide and 3 km long towards northeast. The thickness was estimated a few meters, the flow about 1000 m3 pr second.

Approximately 500 earthquakes were detected in the area and smaller than before. The strongest earthquake, M3.8 was in the Bárðarbunga caldera. Poor weather conditions prevail in the area, which makes detection of smaller earthquakes difficult.

GPS measurements show continued movements north of Dyngjujökull.

Gas emissions rise to a few hundred meters above the fissure.

Weather conditions make it difficult to follow the progression of the eruption, but scientists are in the area, using every opportunity to acquire information on gas and lava outflow.

Weather conditions do not allow overflight at this time. The opportunity to fly over the area will be assessed later today.

— Source

——–

Original post: top

When a volcanic eruption is brewing, people tend to relive the worst of the most recent eruptions.

Volcanologists and emergency management people must be more factual. They need to consider the most current data as well as everything they know about that volcano – and in Iceland, they really know their volcanoes.

In the current volcanic unrest, two Icelandic volcanoes – Bardarbunga and Askja – may be involved, although most activity is happening at Bardarbunga.

A fissure eruption started on August 29th. It was small and located between Bardarbunga and Askja volcanoes. Here is a map of the area from Iceland’s National Land Survey. I highlighted various place names you will encounter below except for the Vatnajokull Glacier, which is pretty obvious.
 

Bardarbunga, Grimsvotn, and the Dyngjujokull lobe of the Vatnajokull glacier are highlighted in yellow.  Askja Volcano, to the north, is highlighted in red.  (Image source)

Bardarbunga, Grimsvotn, and the Dyngjujokull lobe of the Vatnajokull glacier are highlighted in yellow. Askja Volcano, to the north, is highlighted in red. (Image source)

The previous day, GPS data had shown that the dike moving from Bardarbunga was now “interacting with the fissure system of Askja volcano,” so the magma systems of these two volcanoes are connected.

What are Bardarbunga and Askja volcanoes like? How serious is the threat of another disruption of international air traffic? Who else is threatened? Why is this happening? When will we know for sure if the eruption is over? If it isn’t, how long it will last and how bad it will get?

Let’s look at some of the answers to those questions.

Bardarbunga and Askja volcanoes

Iceland has active volcanos because the Mid-Atlantic Ridge – a spreading center between two tectonic plates – rises above sea level here. Parts of Iceland west of the spreading center sit on the North American plate, those east of the center on the Eurasian Plate.

Bardarbunga is located within the spreading center. At 6,592 feet above sea level, it is Iceland’s second highest mountain and is covered by Iceland’s biggest glacier – Vatnajokull.

 

Unlabeled Landsat image from Iceland Met Office

Bardarbunga and Grimsvotn volcanoes have connected magma systems. Askja volcano is to the north, out of sight here. Unlabeled Landsat image from Iceland Met Office

The volcano’s ice-filled caldera is 6 miles wide and about a half mile deep. The volcano’s magma system may be connected to that of nearby Grimsvotn Volcano, as well as Askja’s, further to the northeast.

Bardarbunga has erupted fairly frequently over time. Eruption sites have been in its caldera, on the volcano’s sides, or in fissure swarms to the northeast and southwest up to some 62 miles (100 km) from the volcano’s center.

Some of its eruptions have been big ones. Indeed, Iceland’s largest known eruption, a VEI 6, happened here in 1477. The volcano’s last eruption was a fissure eruption in 1996.

As of this writing, Bardarbunga is under an orange alert.

Lake Oskjuvatn sits in the crater of hte 1875 VEI 5 eruption.  Note the outer caldera in the background.  Source

Lake Oskjuvatn sits in the crater of the 1875 VEI 5 eruption. Note the outer caldera in the background. Source

Askja Volcano is almost 5,000 feet high and has a complex of nested calderas, with Oskjuvatn Lake sitting in the caldera left by a VEI 5 eruption at Askja in 1875. The main crater floor is about 3600 feet (1,100 m) deep. Askja last erupted in 1961.

No glacier covers Askja, but the volcano lies in a remote region and is accessible for only a few months out of the year. Tourists love to bathe in the geothermally heated waters of Oskjuvatn – your mileage may vary (scroll down) – but the region is so dry and bleak that Apollo astronauts trained there.

Icelandic authorities currently have Askja Volcano under a yellow alert.

Current activity and hazards

In 2007, seismic activity picked up at Bardarbunga and at the fissures north of the volcano’s caldera. The number of earthquakes dropped briefly when nearby Grimsvotn erupted in 2011, and then began to rise again and has been ongoing ever since.

In May 2014, Bardarbunga had a swarm of about 200 small earthquakes.

Starting in early June 2014, GPS stations showed displacements indicating that magma was on the move under Bardarbunga.

On July 21, 2014, the largest landslide in Iceland’s history happened on the southeast slope of Askja, causing a tsunami – up to almost 100 feet (30 meters) high, per the Icelandic Met Office – in Lake Oskjuvatn. Fortunately, it was night and there were no tourists or scientists in the area at the time – many people had been there just a few hours earlier.

The Askja slide was accompanied by:

[A] strong and unusual seismic signal, seen even far away from the source region…Similar signals are sometimes seen for strong earthquakes far away from Iceland, however no strong earthquake had been detected by international networks at the same time…As no body waves are seen prior to the low frequency onset, this event clearly differs from a normal tectonic earthquake…

Iceland Meteorological Office

This slide probably isn't related to the Bardarbunga eruption. Icelandic experts point out that this crater area at Askja is very young in geologic terms and may not have stabilized yet. Still, the timing, the size of the event, the unusual tectonic setting on the Mid-Atlantic Ridge, and the current interaction between magma systems all are interesting enough to mention it here.

Things really picked up, beginning in mid-August. Here is a timeline of the current unrest at Bardarbunga, per the Iceland Meteorological Office (which monitors geologic events as well as the weather):

  • August 16: At 3 a.m. local time, an earthquake swarm starts at the volcano and is ongoing . The aviation code is set to orange
  • August 17: Aviation code: Orange. Scientists install additional seismometers at the swarm area with the help of the Icelandic Coast Guard.
  • August 18: Aviation code: Orange. The Icelandic Met Office makes a public statement:

    Since the onset of the earthquake swarm at Bárðarbunga on Saturday morning, around 2.600 earthquakes have been detected with the earthquake monitoring network of the Icelandic Meteorological Office (IMO). Throughout the whole sequence the majority of events has been at 5-10km depth. No signs of migration towards the surface or any other signs of imminent or ongoing volcanic activity have been detected. IMO is monitoring the area closely and will update in case of any changes. A more thorough overview was given in a news-article on the front page.

  • August 19: Aviation code: Orange. About 1,000 earthquakes are recorded, mostly to the east of the caldera, where a cluster is migrating northeastward. Per the Met Office:

    …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 sign of upwards migration has been seen so far. A map of these events was given in a news-article on our front page.

  • August 20: Aviation code: Orange. A reconnaissance flight detects no surface changes at Vatnajokull Glacier. The Met Office issues a public statement:

    There have been no observations of migration to the surface or any other signs of imminent or ongoing volcanic activity. We cannot exclude that the current activity will result in an explosive subglacial eruption, leading to an outburst flood (jökulhlaup) and ash emission.

  • August 21: Aviation code: Orange. More seismic instruments are set up. Scientists meet. They note that the seismic activity is continuing. GPS measurements indicate that an underground intrusion of magma, 16 miles (25 km) long, has formed underneath Dyngjujokull Glacier. It is moving slowly northeastward and isn’t moving upwards. Three earthquakes greater than M3 occur in the caldera, but are thought to be the result of subsidence as magma moves out along the intrusion, not precursors to a caldera eruption.

    The Icelandic Met Office and the University of Iceland issue a joint public statement:

    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. 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. The aviation colour-code for the Bárðarbunga volcano remains unchanged at ‘orange’, signifying that the volcano is exhibiting heightened levels of unrest.

  • August 22: Aviation code: Orange. Another GPS station is set up. Scientists meet again. Intense earthquake continues at Bardarbunga. The magma intrusion continues to expand northward. A M4.7-4.8 earthquake that occurred overnight, as well as other M3-plus quakes, are still considered to be the result of magma withdrawal underneath the caldera. However, they note, “The activity continues and an eruption can therefore not be ruled out.” GPS measurements from all local stations indicate that displacement at Bardarbunga is over 5inches (14 cm), compared to less than an inch (2 cm) for the rest of Iceland.

    The Met Office and the University of Iceland issue the following public statement:

    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. 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. The aviation colour-code for the Bárðarbunga volcano remains unchanged at ‘orange’, signifying that the volcano is exhibiting heightened levels of unrest

  • August 23: Aviation code: Red. Hydrothermal measurements show no unusual river activity. A tourist plane calls in to say no changes have been noted in the glacier.

    Scientists meet. Intense earthquake activity continues GPS activity indicates that magma is still moving. In fact, per the 12:20 p.m. meeting notes:

    During the last 6 hours the dike has propagated ~5 km to the north. The rate of earthquakes has increased such that they are happening so quickly that it is difficult for the seismologist to discern individual events. Observed high frequency tremor is interpreted to be caused by the propagation of the dike.

    An overflight is scheduled for 1 p.m. Soon the aviation warning level is raised to red:

    23rd August 2014 14:10 – a small eruption under Dyngjujökull suspected

    A small lava-eruption has been detected under the Dyngjujökull glacier. (Note: on IMO’s Icelandic web-site this point read “is suspected”; see corrections in English later this day).
    The Icelandic Coast Guard airplane TF-SIF is flying over the area with representatives from the Civil Protection and experts from the Icelandic Met Office and the Institute of Earth Sciences. Data from the equipment on board is expected later today.
    Data from radars and web-cameras is 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.
    Some minutes ago (14:04), an earthquake occurred, estimated 4.5 in magnitude.

    Scientists meet again at around 8:30 p.m. They decide to keep the aviation warning at red, though there are as of yet no signs of changes in the surface of Vatnajokull and no meltwater flooding out from the glacier’s edges. Harmonic tremor has been detected during the day, indicating an eruption, but no one yet knows if it will remain under the glacier or break through.

  • August 24: Aviation code: Orange. Scientists meet. Two earthquakes bigger than M5 have happened overnight in the caldera. Seismic activity under the northwest part of Vatnajokull is very strong (around 1,300 quakes, mostly around the northern edge of the intrusion). More than 20 events at the edge of the instruction are greater than M3. The underground magma intrusion is moving northward and is now over 19 miles (30 km) long. There are no signs of upward magma movement or of harmonic tremor.

    The Met Office and the University of Iceland issue a joint statement:

    There are no indications that the activity is slowing down, and therefore an yesterday. The intense low-frequency seismic signal observed yesterday has therefore other explanations. The Icelandic Meteorological Office has decided to move the aviation colour-code from red to orange.

  • August 25: Aviation code: Orange. Seismic activity remains strong. Scientists meet. The magma intrusion is still moving northward, now about 22 miles (35 km) long, and estimated to contain 300 million cubic meters. The Met Office and the University of Iceland say:

    There are no indications that the intensity of the activity is declining. Currently, three scenarios are considered most likely:

    1) The migration of magma could stop, attended by a gradual reduction in seismic activity.

    2) The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dike. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.

    3) An alternate scenario would be the dike reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity. Other scenarios cannot be excluded. For example, an eruption inside the Bárdarbunga caldera is possible but presently considered to be less likely.

  • August 26: Aviation code: Orange. A M5.7 earthquake occurs in the caldera overnight. The underground intrusion of magma is some 25 miles (40 km) long. GPS measurements indicate an additional 50 million cubic meters entered the intrusion over the past 24 hours.

    The IMO and University of Iceland say:

    There are no indications that the intensity of the activity declining. Currently, three scenarios are considered most likely:

    1) The migration of magma could stop, attended by a gradual reduction in seismic activity.

    2) The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dike. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.

    3) An alternate scenario would be the dike reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity. Other scenarios cannot be excluded. For example, an eruption inside the Bárdarbunga caldera is possible but at present considered to be less likely.

  • August 27: Aviation code: Orange. Another 20 million cubic meters of magma has entered the intrusion over the last 24 hours. Strong earthquakes occur at both Bardarbunga and Askja. Seismicity is ongoing, with some 1,300 quakes. Scientists say, “Modelling results suggest that the dyke intrusion is causing stress changes over a large area, including the region to the north of the dyke’s extent; this could account for the increased seismicity at Askja volcano.”

    An overflight identifies crevasses and a long line of 10-15 m deep cauldrons in the Vatnajokull Glacier south of Bardarbunga’s caldera. There is no sign of harmonic tremor.

  • August 28: Aviation code at Bardarbunga: Orange. Aviation code at Askja changed from green to yellow.

    28th August 2014 12:35 – from the Scientific Advisory Board

    Scientists from the Icelandic Meteorological Office and the Institute of Earth Sciences, together with representatives of the Civil Protection in Iceland, met today to discuss the on-going unrest at the Bárðarbunga volcano.

    Conclusions of the Scientific Advisory Board:

    This morning, there was a flight over the Bárðarbunga area and the surface of the glacier was surveyed. No changes to the ice crevasses southeast of Bárðarbunga, that were seen yesterday evening, were observed. These crevasses were likely formed due to melting at the ice bottom.

    The depressions have been located southeast of the Bárðarbunga caldera, in all likelihood within the water divide of the river Jökulsá á Fjöllum. There are three circular crevasse formations, about 5 km in total length. The ice thickness in the area is 400-600 m.

    The water level in Grímsvötn Lake has been surveyed and has likely risen by about 5-10 m in the last days, which corresponds to an addition of 10-30 million m³ of water in the lake. A slight increase in conductivity in Köldukvísl River was measured this morning, but the cause is yet unknown. No change has been measured in the Hágöngulón lagoon, Jökulsá River and Skjálfandi River. It is assumed, that the water from the cauldron has flowed into the Grímsvötn Lake or the river Jökulsá á Fjöllum.

    The seismic activity is similar to that of the last days. Around midnight, three earthquakes of magnitude around 4 were recorded and one of magnitude 5 at 08:13 this morning, all located within the Bárðarbunga caldera.

    Shortly before 08:00 this morning, there was a slight increase in seismic activity in the Askja volcano. Changes in the stress field due to expansion caused by the dyke have an effect on the Askja area.

    Since yesterday, the length of the dyke under Dyngjujökull has increased by 1-1.5 km to the north, which is considerably less than in the last days. The dyke has now reached the fissure system of the Askja volcano and GPS measurements indicate that the area there is greatly affected.

  • August 29: Oooh!
     

    Aviation code for Bardarbunga: Still orange, in spite of the eruption, as no ash is expected from the activity. Aviation code for Askja: Yellow.

    29th August 2014 02:45 – An eruption started in Holuhraun north of Dyngjujökull at around 00:02. Seismic tremor was observed on all seismic stations and the web camera installed in the area by Mila has showed some nice pictures of the eruption. It is a small fissure eruption and at 02:40 AM the activity appears to have decreased.

    29th August 2014 07:10 – from geoscientist on duty

    Seismic activity has decreased as a result of the pressure release, however a significant amount of earthquakes is still detected in the magma dike, between the eruption site and south to about 5 km into Dyngjujökull.

    Strongest events were 3.8 in the caldera of Bárðarbunga at 04:37, as well as 2.9 at 05:39 and 3.5 at 06:38 in the dike. These earthquake are very closely monitored, but no significant change volcanic activity following these has been observed so far.

    The Met Office and the University of Iceland issue a joint statement:

    At this moment it is unclear how the situation will develop. However, three scenarios are considered most likely:

    * The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.

    * The dike could reach the Earth’s surface north of Dyngjujökull causing another eruption, possibly on a new fissure. Such an eruption could include lava flow and (or) explosive activity.

    * The intrusion reaches the surface and an eruption occurs again where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.

    At 10:00 UTC, IMO changed the Aviation Colour Code for Bárðarbunga to ‘orange’, signifying that significant emission of ash into the atmosphere is unlikely. The aviation colour-code for the Askja volcano remains at ‘yellow’. Other scenarios cannot be excluded. For example, an eruption inside the Bárdarbunga caldera.

  • August 30: Aviation code at Bardarbunga: Orange. Askja: Yellow. Over 20 microquakes are detected at Askja. Scientists believe this is because of changes in the local stress field north of the dike intrusion. Lava samples are collected.

    Scientists decide strong earthquakes in the caldera region may not just be the result of subsidence as magma flows out into the intrusion:

    The largest earthquakes since midnight include: (i) a magnitude 4.5 event on the northern side of the Bárðarbunga caldera at 02:35 UTC; (ii) a magnitude 4.2 earthquake in the same region at 06:18 UTC; and (iii) a magnitude 5.4 earthquake on the south-eastern edge of the Bárðarbunga caldera at 07:03 UTC. During the last two weeks, several earthquakes of similar size have occurred on the edge of the Bárðarbunga caldera. These earthquakes are interpreted as signs of stress changes in the region of the caldera.

    Now they’re considering four possible scenarios, including an eruption at Bardarbunga’s caldera:

    * The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.

    * The dike could reach the Earth’s surface north of Dyngjujökull causing another eruption, possibly on a new fissure. Such an eruption could include lava flow and (or) explosive activity.

    * The intrusion reaches the surface and an eruption occurs again where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.

    * An eruption in Bárðarbunga. The eruption could cause an outburst flood and possibly an explosive, ash-producing activity. In the event of a subglacial eruption, it is most likely that flooding would affect Jökulsá á Fjöllum. However it is not possible to exclude the following flood paths: Skjálfandafljót, Kaldakvísl, Skaftá and Grímsvötn.

So here we are as of the time of this writing. To this amateur, it looks like something – who knows what, but probably nothing immediately threatening – is going on between Bardarbunga and Askja. The greatest hazard from this ongoing eruption right now could be massive meltwater flooding as the second highest volcano in Iceland heats up underneath the country’s largest glacier.

If the eruption does happen and then breaks through to the surface, it will likely be at least as explosive as Eyjaf’s eruptions were in 2010. But no one can say yet if or when that might happen.

Further updates on Bardarbunga and Askja, including one for today, August 31 (since this is scheduled to be posted before I can check the latest online news), will be posted at the top of this post as needed. I hope the volcanic activity doesn’t increase today, since former Hurricane Cristobal’s remnants will be passing through. top

Online resources

The most in-depth and up-to-date information online is at the Icelandic Meteorological Office website (it’s in English – just look at the top of the page for “Bárðarbunga & Dyngjujökull”).

The National Land Survey of Iceland has made some detailed maps (English) of the Bardarbunga area.

Dr. Erik Klemetti’s “Eruptions” blog is a useful reference, both in the post and in some of the comments.

The London Volcanic Ash Advisory Centre is a good place to check for news of an eruption, too. All VAACs constantly monitor the airways for volcanic ash threats.

Should there be a significant eruption at Bardarbunga, a satellite image of it might appear at this National Oceanic and Atmospheric Administration website. top

 
 
 


 
Sources:

Front page image (Icelandic)

top



Categories: Sunday morning volcano

Tags: , , , ,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: