Dyke intrusions – Page 38 – Iceland geology

August 30, 2014August 30, 2014

Update on Askja and Bárðarbunga volcanoes at 17:49 UTC

This information is going to get outdated quickly.

This is the weekend edition of my regular updates on activity in Bárðarbunga and Askja volcano. They are shorter and might not contain all the information on what is going on.

Current status on Askja volcano

Askja continues to be on Yellow alert.
Dyke does not seems to have any progress moving into Askja volcano system. Reason why that is are unknown.
Earthquake activity appears to have dropped in Askja for the past 24 hour period.

Current status on Bárðarbunga volcano

Largest earthquake for the past 24 hours is a magnitude 5,4 earthquake that took place at 07:03 UTC. It took place in south-west part of Bárðarbunga volcano. It did appear clearly on my geophones and they can be viewed here.
Eruption has been confirmed to have taken place on 23-August-2014. That eruption did not manage to break the trough the glacier since it is 400 to 600 meters thick were the eruption took place.
Most earthquake activity is taking place on 15 km long line in the Dyke, starting at the location were the eruption took place and goes some 15 km south from that location. Dyke does not seems to be moving north at the moment.
Eruption is now considered more likely in Bárðarbunga volcano it self than before.
Last large eruption that took place in Bárðarbunga volcano was in 1717. According to Global Volcanism Program that eruption was an VEI 3 eruption.
Eruption can happen in slopes of Bárðarbunga volcano, also in its caldera. The glacier in the caldera is up to 800 meters thick (+- 100 meters).
Earthquake activity is stable, with over 1000 to 2000 earthquakes recorded daily so far.

GPS data

Icelandic Met Office has released GPS data and it can be viewed here.

Storm warning

There is going to be a storm in Iceland on Sunday. This means fewer earthquakes are going to be detected due the wind noise.

News bits in English

Eruption at Bardarbunga now more likely (Rúv.is)
Fresh ice cracks in Bárðarbunga? (mbl.is)

Updates during the weekend

I am going to post updates during the weekends. I do however need to take a little break since I’ve been working and writing about Bárðarbunga for the past two weeks. So updates on weekends are going to be shorter and less detailed than on working days (Monday – Fridays). If eruption happens I am going to post information about that eruption soon as I become aware of it and details soon as possible.

Article updated at 17:52 UTC.
Article updated at 18:10 UTC.
Article updated at 19:01 UTC. I corrected information about the dyke earthquake location.

August 29, 2014August 30, 2014

Status update on Askja and Bárðarbunga at 18:35 UTC

This information is going to get outdated quickly.

For the media (news) please note! I am not a professional geologist. I got all the same knowledge as they do, but I am not a professional geologist. For professional view on what is going on please contact Icelandic Met Office or University of Iceland, Geology department.

Askja volcano

This is the current information that I got on Askja volcano.

Dyke from Bárðarbungu volcano continues into Askja volcano. It has slowed down according to reports from yesterday. I have not seen any reports on its process today.
Earthquake activity is increasing in Askja volcano. This is due to effects from the dyke.
Askja continues to be on Yellow alert status.

Bárðarbunga volcano

This are current informations that I got on Bárðarbunga volcano.

The eruption is over for now. It only lasted 3 – 4 hours.
This eruption was only lava. No or almost no volcano ash was put into the atmosphere. Some water vapour was seen (the white clouds) after the eruption ended.
The eruption took place in a fissure that last erupted in the year 1797. That eruption created Holuhraun lava field. This eruption took place in a crater row.
The eruption fissure was 900 meters long according to news in Iceland today.
Earthquake activity dropped while the eruption took place. It has increased again. I did see on my geophones an earthquake swarm as the eruption reached its peak.
This is the first time I see an eruption in a older crater row. This might be normal for this area of Iceland.
Future eruptions can happen at any time while current activity continues in Bárðarbunga volcano.
Largest earthquakes today was a magnitude 5,2 earthquake, second largest earthquake today was a magnitude 4,8 and third largest earthquake today was a magnitude 4,1.
Earthquake activity continues to be high, with over 900 earthquakes recorded so far today (according to my earthquake counter).
Harmonic tremor is on same level as it has been on since 16-August-2014.

Analyse of the eruption

The eruption started around 00:02 UTC, when it was first visible on Míla web cameras. I was notified of this by a person watching the cameras over Facebook around 00:30 UTC. According to Rúv news and other news sources the eruption peaked at 01:20 UTC. It was over around 04:00 UTC. The volume this eruption placed on the surface was minor, it had no impact on the magma that is in the dyke. Future eruptions on this fissure cannot be ruled out. As stated above last eruption took place on this same fissure in the year 1797.

This is the second confirmed eruption in Bárðarbunga volcano since this started. With the first one being on 23-August-2014. When a similar minor eruption took place. That eruption was under glacier (up to 600 meters of it) and was not observed for that reason. This new period of activity in Bárðarbunga volcano is possibly going to last for years, if only based on the volcano eruption history as it is documented on Global Volcanism Program website. I am at least preparing to write about Bárðarbunga for a long time now.

I am going to write notification about new eruptions soon as I become aware of them. The weather forecast for the next few days is not good. So visibility is going to be limited in the area close to Bárðarbunga.

Images of the new lava and mixture of old and new craters can be found here.

Article updated at 18:43 UTC.
Article updated at 18:51 UTC.
Article updated at 19:10 UTC.
Article updated at 15:14 UTC on 30-August-2014.

August 29, 2014

Eruption has started on the fissure swarm

Eruption has started in the dyke area. The eruption appears clearly on Míla web camera. It can be viewed here.

More details later.

August 29, 2014August 29, 2014

Update on Askja and Bárðarbunga volcanoes at 22:21 UTC

This is a short update on Askja and Bárðarbunga volcanoes. This information is going to get outdated quickly. I am not going to use pictures from now on (in most cases), since the situation now is complex and is going to go more complex as this goes on.

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Askja volcano

The dyke from Bárðarbunga volcano continues its journey into Askja. It has not yet reached Askja magma chamber. When that is going to happen is unclear at the moment.
Activity has been picking up in Askja due to stress changed from the dyke.

Bárðarbunga volcano

Dyke activity continues at similar rate as before. It is now moving about 1 – 2 km a day according to latest news. The dyke has reached Askja volcano main system, it has not reached Askja main magma chamber. Once that is breached earthquake activity along with harmonic tremor in Askja is going to trough the roof.
Eruption on 23-August-2014 has been confirmed. It only lasted for 1 – 2 hours before it died down. I think current ideas why it happened are wrong. From my perspective it happened due to magma pressure inside Bárðarbunga magma chamber reaching a high point (highest so far). This did mean that the dyke was not able to tap off the magma chamber at fast enough rate for a short while. Allowing magma to breach the crust at other locations. While this was a short event, this suggests that magma is coming into Bárðarbunga magma chamber at depth. So far the volume that is flowing in is low for the moment. I suspect that might change at any time and without any warning.
The reason why the ice cauldron did not appear sooner is that it took the water some time to dig its own path trough the glacier. Why it did go to Grímsvötn lake (Grímsfjall volcano) I do not knwo.
Earthquake activity remains high in the north end of the dyke. Earthquake activity is present in Bárðarbunga volcano (main volcano), but it is not constant at the moment. That might change without warning.
No dyke activity so far going south of Bárðarbunga volcano.
Cracks appearing in the crust suggest that the dyke depth is only about 2 km at most. This has also allowed for groundwater warning up in areas. This has been seen under areas were the glacier is thin. This is creating hot springs and hydrothermal areas along the dyke path.
Inflation so far is around 40 cm to the east and west. There is nothing to suggest it is going to slow down at the moment.
This might be a long eruption once it starts. How long I do not know. At most some years, as has happened in Bárðarbunga volcano in the past.
Today there has been minor “quiet” time in Bárðrabunga. Harmonic tremor has been stable and no cycle of up and down has taken place. In my view that might change in next hours. I am already seeing changes in the tremor plot that suggest this.

The situation is highly dynamic and is going to change rapidly at times. So this information is going to get outdated quickly for that reason. For wind, weather and earthquake information in Iceland please check Iceland Met Office website. My geophone website can be viewed here.

Article updated at 23:33 UTC.

August 28, 2014August 28, 2014

Update on Bárðarbunga and Askja volcanoes at 13:34 UTC

This is a none picture update on Askja and Bárðarbunga volcanoes. The reason for this none picture update is that I haven’t had time to work on the images yet. This is the first time this has happened in Iceland since modern recording started. What is going to come out of this I do not know yet.

If you are in the area. Please don’t go into the closed area. There are fines for during so and it is also extremely dangerous since we don’t know properly what happens and risk of sudden flood is high and growing. Eruption might start at any time without warning, both outside the glacier and inside the glacier. If an eruption takes place in a glacier covered area, that means sudden glacier flood that are going to kill you if you are in flood path. In such glacier flood it is not just mud, volcano material, but also an ice bergs that are larger than 5 floor houses. If you get lost in such flood, the chance of being rescued from such flood are none. If you want to watch what is now unfolding do so at the save distance, this show is going to big according to my earliest estimate and guess work (not going to publish that here).

Askja volcano

The dyke from Bárðarbunga volcano has entered Askja volcano. Not the fissure swarm, the volcano it self.
Askja volcano status has been elevated to Yellow.

Bárðarbunga volcano

Cauldrons in Vatnajökull glacier that is on top of Bárðarbunga volcano have not grown during the night.
The water seems to be flowing into Grímsvötn (Grímsfjall volcano) lake. It has risen close to 15 meters in the past few days.
Earthquake activity is high. Both in the main volcano were a magnitude 5,4 earthquake (EMSC magnitude, USGS magnitude) took place today (28-August-2014) at 08:13 UTC. The earthquake took place in the caldera rim as most of the large earthquakes have happened.
Over 1300 earthquakes happened yesterday in the north end of the dyke swarm.
Cracks have started to happen in the crust above the dyke. This means the dyke is getting wider and is higher up in the crust then suggested by earthquake activity. There are reports of small cauldrons in Dyngjujökull glacier in the area, in the place were the glacier is thinnest and ending.
Harmonic tremor remains high on all SIL stations around Bárðarbunga volcano.

The situation is extremely dynamic and is going to change fast in next 24 to 48 hours. I am now close to 80% sure that an eruption is going to take place in both Askja volcano and Bárðarbunga volcano, since minor eruptions have been taking place under the glacier already.

August 28, 2014August 28, 2014

Unclear what is happening in Bárðarbunga volcano

This information is going to get outdated extremely fast.

Earthquake activity remains high.
Cauldron have formed in Vatnajökull glacier just SE and SSE of Bárðarbunga volcano.
The cauldrons are 4 to 6 km long and about 1 km wide.
No harmonic tremor have been seen, but that might have its own reasons.

Earthquake activity in Bárðarbunga volcano for past 48 hours. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity remains dense in Bárðarbunga volcano for the past 48 hours. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor remains high on Dyngjuháls SIL station. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor is also high on Kreppuhraun SIL station. Copyright of this image belongs to Icelandic Met Office.

The cauldrons that have been spotted today in Vatnajökull just SE and SSE of Bárðarbunga volcano are in the south end are of the current dyke. What is also important, they are also in an area were magnitude 5,0 earthquake did happen few days ago, in a area that has not had any dyke activity since 16-August-2014 when this all started. It is still unclear what happened to all the water in this melt, the glacier in this area is 400 to 600 meters thick and this is not a little melt that has taken place in the glacier. There is a chance the water did go to Grímsvötns lake (caldera like in Grímsfjall volcano), but that remains unclear at the moment.

I am going to post more information about this once I have them.

Updated at 00:14 UTC on 28-August-2014.

August 27, 2014August 27, 2014

Bárðarbunga volcano update at 00:31 UTC

This information is going to get outdated quickly.

This is the short update on status on the activity in Bárðarbungu volcano.

Current activity is mostly unchanged. Earthquake activity remains high and there are around 1000 earthquakes every 24 hours.
According to the news today and Icelandic Met Office data, the dyke doesn’t appear to be getting longer. It is now around 37 km long.
Largest earthquake since 2008 took place in Bárðarbunga volcano on 26-August-2014 at 01:26 UTC. It had the magnitude of 5,7 and took place in Bárðarbunga caldera. Second medium earthquake took place today at 11:56 UTC and had the magnitude 4,6. It was felt in Akureyri.
There are no signs of magma going to the surface as of writing of this article. I do expect that change quickly.
It is now my view that after the magnitude 5,7 earthquake the risk of an eruption Bárðarbungu caldera has increased from what it was. I don’t know yet if an such eruption is going to take place. I however find it to be the most likely outcome based on current status.

The magnitude 5,7 earthquake that took place on 26-August-2014 is the strong earthquake in Iceland since 2008, when a magnitude 6,3 earthquake happened between Selfoss town and Hveragerði in the South Seismic Zone in Iceland (often just called SISZ). Earthquake activity remains high in the north end of the dyke, with strongest earthquake today having the magnitude 4,6. With many more magnitude 3,0 and stronger earthquakes taking place. There are still over 1000 earthquakes being recorded every 24 hours in area where the dyke is located (about 20 km east of Trölladyngja).

Earthquake activity in Bárðarbunga volcano today. This map is already outdated. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity remains extremely dense in the dyke from Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

Total lack of earthquake at the start of the dyke suggest that the flow of magma is now smooth and it is flowing without any resistance to the north end of dyke. Where the dyke seems to have hit a resistance in the crust that he is not able to break at current time. I don’t know if the earthquakes that have been taking place today are going to change that. But if this resistance in the crust holds there is a chance it there are going to be even large earthquakes that are going to take place at this location. What magnitude is to expect is difficult to know for sure, but the crust in this area is able to make earthquakes above magnitude 5,5, but how far up the scale it goes I do not know.

There has been some deep earthquake activity taking place according to the automatic data, but since it is automatic data it might be wrong. The deepest earthquake that I did see to day took place today had a automatic depth of 29,3 km with quality of 90,10. There is a chance this dyke might get into connection of other deep dyke in this area. This are dykes that form deep in the crust at depth of more then 30 km, they don’t make any earthquakes when they form since the crust material in this region of the crust is soft and is unable to break and does not make an earthquake as result. I do not know what happens if this dyke manages to connect to an dyke that might have formed in the deeper range of the earth crust in this area. It is also a highly unlikely outcome, for the moment however it is not impossible. Since the dyke now has problems pushing north, and as an result of that it seems to be pushing a little bit down as result. It is clear that once it can not extent any future down or to the sides, it is going to go up. I am not expecting the flow of magma into the dyke to drop any time soon. That might happen, it is just unlikely to happen given the current data. Estimated amount of magma is around 350 million m³ today (26-August-2014).

Harmonic tremor remained high in Bárðarbunga volcano due to magma flow in the dyke. This is Dyngjuháls SIL station. Copyright of this image belongs to Icelandic Met Office.

Here is the harmonic tremor in Bárðarbunga on the SIL station in Kreppuhraun. Copyright of this image belongs to Icelandic Met Office.

The harmonic tremor shows that the dyke inflow continues as I did write about above. It also shows one important thing, the flow of magma into the dyke and presumably into Bárðarbunga volcano is not even. It happens in short periods of high inflow with lower periods between them.

GPS data show the magma continues to flow into the dyke at 5 to 10 km depth. More GPS plots can be found here. Copyright of this image belongs to University of Iceland.

The magnitude 5,7 earthquake as it appeared on my geophone in Heklubyggð. This image is released under Creative Commons licence. See CC Licence page for more details.

The magnitude 5,7 earthquake as it appeared on my geophone in Böðvarshólar. This image is released under Creative Commons licence. See CC Licence page for more details.

What this has told me is that there is far more magma in Bárðarbunga volcano then appear at first sight. How much of it can actually erupt in an eruption I do not know. But this seems to be far more complicated then I first thought, it is not just a dyke pushing out of Bárðarbunga volcano. There is also a lot more magma inside the magma chamber that is starting to look for an way out, at least from the looks of current activity. The glacier inside the caldera is 700 meters thick so the magma inside the magma chamber that is directly below the caldera is under this extra pressure from the glacier. Once that magma overcomes the pressure of the glacier an eruption is going to start in the caldera, until that time we might see more dyke activity going north and south of Bárðarbunga volcano. Since the magma is going to go first the easiest way out. How much pressure has to be inside the magma chamber to overcome the pressure of the 700 meter thick glacier inside the caldera I do not know. All I know is that it is a high number on any pressure scale.

As of this writing a new magnitude 5,1 (more on EMSC website here) has taken place in Bárðarbunga volcano caldera. Larger earthquake appear clearly on my geophones that can be viewed here.

August 25, 2014August 27, 2014

Bárðarbunga volcano update at 20:49 UTC

This information is going to get outdated quickly. Minor spelling note. ~~It appears that dike is spelled with a simple “i” not a “y”.~~ Information on what volcano dyke is can be found here on USGS website. Added: That is in U.S English, UK English uses Dyke so I am going to use UK English. Thanks to Squonk to pointing me to this information.

Special note on Askja volcano

There are many people speculating that the dyke might reach into Askja volcano. I find that to be unlikely outcome. That does not appear to have happen in the past and I don’t think the geology setting allows for it. The area is full of old dykes that have cooled into granite type of rock (and other hard types of rock) in the crust (this is a volcano area and I find this to be likely). Given the density and how hard granite is I find it unlikely that this magma is going to break it. It has been crossing softer rock in the crust for the past week. What I can’t rule out is that Bárðarbunga volcano might start an eruption in Askja volcano by some other mechanism that might or might not be well understood. Askja volcano did start to prepare for eruption cycle in the year 2010 (earthquake swarm at 20 km depth was the clue), but the process appears to be slow, at least the volcano doesn’t appear to be ready for an eruption as things look now.

Special note on Tungnafellsjökull volcano

Yesterday (24-August-2014) an magnitude 3,0 earthquake took place in Tungafellsjökull volcano, a small volcano west of Bárðarbunga volcano. There had been few other earthquakes also yesterday, just smaller. Currently there is nothing suggesting that Tungafellsjökull volcano is about to erupt. There has been earthquake activity taking place in Tungafellsjökull volcano during the past year, suggesting that the volcano is experiencing flow of new magma at depth (more then 15 km depth), but there isn’t anything to suggest that an eruption is imminent in it. There is also a good chance that current earthquake activity in Tungafellsjökull volcano is due to stress changes in the crust that are taking place due to the caldera of Bárðarbunga volcano is getting lower (more on that later in this article). I don’t think Bárðarbunga volcano is able to start an eruption in Tungnafellsjökull volcano, but this is also an volcano that has never erupted during historical times and current data suggest it might not have erupted at all during the last 10.000 years (or more). Tungafellsjökull volcano is located west of Bárðarbunga volcano, it has a green star on it currently (as of this writing) on Icelandic Met Office earthquake maps.

Bárðarbunga volcano update

Earthquake activity remains strong in Bárðarbunga volcano. Medium sized (magnitude 5,0 – 5,9) earthquakes (more information here)) have been taking place as the caldera gives away due to outflow of magma from the magma chamber in Bárðarbunga volcano. This appears to be happening due to less inflow of magma from depth (the mantle). The crust in this part of Iceland is up to 46 km thick due the mantle plume beneath it (more information in details here, warning a large pdf file). The lowering of the caldera is creating stress changes in the area. What the end result of that is going to be I don’t know, since the crust is slower to respond, but as more stress is build up in the area this way stronger earthquakes can be expected at later time.

Currently the dyke is now at location that last erupted in the year 1797, it has remained bit unclear if it was Bárðarbunga or Askja that started that eruption. Chemical analyse says the lava is from Bárðarbunga volcano, not Askja volcano. This is according to the news I did hear today. Currently the dike north end is now 20 km east of Trölladyngja. Earthquake activity has been picking up and increasing in that area for the past 24 hours. It however doesn’t appear to be as high as it is on the main area of the dyke (about 20 km ENE of Kistufell, north of Dyngjujökull glacier, just check the earthquake map if you are confused by this).

The earthquake activity for the past 48 hours in Bárðarbunga volcano. Green stars show earthquakes with higher magnitudes then 3,0. Copyright of this image belongs to Icelandic Met Office.

The earthquake activity during the past 48 hours in Bárðarbunga volcano has been dense. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor remains high on Dyngjuháls SIL station. It goes up and down in accordance with the magma inflow into the dike. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor is also high on Askja SIL station. Same movement can be seen as on Dyngjuháls SIL station. Copyright of this image belongs to Icelandic Met Office.

GPS data shows that more magma has flowed into the dyke during the past 24 hour. More GPS stations can be found here. Copyright of this image belongs to University of Iceland.

In the news today in Iceland I have seen that there is now some discussion that this dyke might not erupt at all. Since it appears both to be getting deeper in some areas and there are currently no signs of it going upwards. The problem with this is the idea is in my view based on wrong parameters so I don’t agree with it. This dyke is going to erupt in my view, it is just a matter of time now. It might not erupt, that is always a possibility. I just think it is highly unlikely to be the outcome of all of this. This dyke is going to continue making a path for it self until it hits a resistance in the crust it cannot break after that it is going to go up, since its easier path for it, rather then to go down into the crust where its path has more resistance. When that might happen is something that I do not know.

Article updated at 21:03 UTC.
Article updated at 21:26 UTC.
Article updated at 00:13 UTC on 26-August-2014.
Article updated at 10:35 UTC on 26-August-2014.

August 24, 2014August 24, 2014

Short update on Bárðarbunga volcano at 12:07 UTC

This is a short update on Bárðarbunga volcano. Due to the fast change that is now taking place in Bárðarbunga volcano this information is going to get outdated quickly.

Earthquake activity now is extremely dense. With 3 to 5 earthquakes taking place every second (best estimate that I have made).
Earthquakes have increased in magnitude.
General activity appears to have increased in Bárðarbunga volcano. Even if no major eruption has yet taken place.
There is currently no signs of this activity stopping any time soon.
The dyke in Bárðarbunga volcano continues to get longer and wider, it is now over 40 km long (I think). Formation of this dyke has slowed due to more difficult crust in the area he is now in (that means more earthquakes).

The current earthquake activity in Bárðarbunga. Copyright of this image belongs to Icelandic Met Office.

The extremely dense earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor is getting off the tremor plot that Icelandic Met Office has on its website. This is the harmonic tremor at 11:33 UTC. This is Dyngjuháls SIL station. It is closest to the dyke at the moment. Copyright of this image belongs to Icelandic Met Office.

The SIL station in Askja volcano is also showing the massive activity in Bárðarbunga volcano. This is the harmonic tremor at 11:33 UTC. Copyright of this image belongs to Icelandic Met Office.

Current length of the dyke from Bárðarbunga volcano. Blue dots are the oldest and the red ones are the newest. This shows the earthquakes from 16-August-2014. Copyright of this image belongs to Icelandic Met Office.

The harmonic tremor seems to increase when there is a new flow of magma at depth into the dyke. Large earthquakes happens in Bárðarbunga caldera when it adjust to this flow out of the magma chamber above it. There are clues that magma at depth might have triggered this, but there is a lack of deep earthquakes in Bárðarbunga volcano so it is difficult to say for sure.

This is the magnitude 5,3 earthquake that took place today (24-August-2014) at 00:09 UTC. This is my geophone in Heklubyggð. This image is released under Creative Commons Licence. Please see CC Licence page for more details.

This is the magnitude 5,3 earthquake that took place today (24-August-2014) at 00:09 UTC. This is my geophone in Böðvarshólar. This image is released under Creative Commons Licence. Please see CC Licence page for more details.

This is the magnitude 5,1 earthquake that took place today (24-August-2014) at 05:33 UTC. I use data from EMSC that explains different magnitude in the image. This is my geophone in Heklubyggð. This image is released under Creative Commons Licence. Please see CC Licence page for more details.

As explained above the earthquake activity is dense under Dyngjujökull at the moment. The dyke is also now in part on glacier free area, so if any minor eruptions happen they can be seen on the surface. The dyke seems to be under high pressure, but I don’t know yet if that is going to result in an eruption. But I find it highly likely at this point and given current data.

My geophones can be seen here. Some of the activity that is now taking place in Bárðarbunga appears on them. Larger earthquakes (magnitude 3,5 and above) appear always at this distance. Wind appears on my geophones if weather is bad in Iceland.

Updated at 14:12 UTC.

August 23, 2014

Smallest of eruptions so far (Bárðarbunga update at 20:43 UTC)

This is a short update and this information might go outdated quickly.

It appears that the eruption that took place in Bárðarbunga volcano was a minor one. It also looks like that the eruption was so small that it didn’t even make dent in the glacier on top of it, but the glacier in this area is around 400 meters thick. Such minor eruptions are not common in Iceland, but they do happen once in a while.

Earthquake activity today (23-August-2014) in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake today had the magnitude of 4,5 (EMSC information here) – 4,7 (USGS). Other earthquakes that have taken place today have been smallers, few earthquakes with magnitude above 3,0 also took place today.

The harmonic tremor that took place in Bárðarbunga volcano today. It makes a clear mark from the other magma movement that has been taking place during the past week. This is Dyngjuháls SIL station. Copyright of this image belongs to Icelandic Met Office.

This harmonic tremor was also visible on Kreppuhraun SIL stations. Copyright of this image belongs to Icelandic Met Office.

GPS data showing current inflation on Dyngjuhjáls. More plots can be found here. Copyright of this image belongs to University of Iceland.

Current GPS data show that inflation to the north has stopped, while inflation to the west has increased and up to 2 to 3 cm a day based on newest GPS data. This means that more magma is flowing into the dyke on 5 to 10 km depth. The dyke continues to extent, but now it is moving more north rather then north-east as before.

The eruption that took place today was a minor one. I am not even sure it lasted a whole hour, but since it was under a 400 meter thick glacier that is only guess work on my end based on tremor data that I have. This might however not be the last eruption in Bárðarbunga volcano, far from it. Short eruptions like this one might happen on regular basis now in Bárðarbunga volcano and not all of them are going to take place under glacier in my view.

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