Swarm – Page 90 – Iceland geology

August 17, 2014

Update on activity in Bárðarbunga at 18:13 UTC

This is a update on the activity in Bárðarbunga volcano. This information might get outdated quickly as things change.

Earthquake activity continues in Bárðarbunga volcano with no signs of stopping. Since midnight the total earthquake count for Iceland has now reached 578 (at 18:14 UTC) this number gets outdated quickly due the continuous earthquake activity in Bárðarbunga volcano. The total amount of earthquakes recorded yesterday was around 480 for the whole day, so it seems that earthquake activity has increased today from what it was yesterday. It is possible to see the largest earthquakes on my geophone website here. I want to note that my geophones are both more then 100 km away from Bárðarbunga volcano, so only the largest earthquakes appear on my geophones.

The earthquake activity in Bárðarbunga volcano. It has now moved into two groups of activity. Copyright of this image belongs to Icelandic Met Office.

The earthquakes are forming an line south-south-east in Bárðarbungu volcano. I don’t know why that is, but this might be a feature of the SIL network, rather then actual alignment of the earthquakes. There also chance that the earthquakes really are aligning them self into a line like this.

Earthquake activity continues to be dense. A minor drop in activity was seen around 12:00 UTC, but it increased again around 13:00 UTC. Copyright of this image belongs to Icelandic Met Office.

There has been little drop in activity, besides the drop in activity seen around 12:00 UTC, that drop in activity however only lasted for about one hour, maybe less. There has overall not been much change in activity during the past 24 hours. I don’t know if that is going to change, but for the moment there are no signs of the activity slowing down.

Harmonic tremor at Dyngjuhálsi SIL station. It moves up and down with the earthquake activity. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor at Vonaskarð SIL station. It shows the changes in activity as other SIL stations around Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

There are interesting theories on why the harmonic tremor is as it is. Currently there is nothing to suggest that an large eruption has taken place, there is a chance that a small eruption started all this, but I expect by now that it is over if it took place. It has not been confirmed. There is also a chance that earthquake activity is so high in Bárðarbunga volcano that it is registering as continuous harmonic tremor. It does not happen often, but it can happen. There is also chance that the harmonic tremor is due to boiling of hydrothermal systems in Bárðarbunga volcano, or something other related to magma under heavy pressure. Whatever the reason for this tremor, it’s there and an eruption does not seems to be the reason behind it.

Visual observations have now been made of Bárðarbunga volcano and nothing has been seen on the surface of the glacier. Scientists are also installing new monitoring hardware and a web-camera on Bárðarbunga volcano in order to get proper visual observations of the volcano when something happens. I don’t expect the web-camera to be a public at the moment.

August 17, 2014August 17, 2014

Short update on Bárðarbunga volcano at 02:12 UTC

This is a short update on Bárðarbunga volcano activity.

Earthquake activity continues in Bárðarbunga volcano and shows no signs of slowing down. Two swarms have appeared in Bárðarbunga volcano system. One is at location called Kistufell, while the second one is at the south-east part of the Bárðarbunga volcano. Increase in earthquake activity in south-east part of Bárðarbunga volcano seems to increase harmonic tremor. I am not sure why that is. As of now (when this is written) no eruption has been confirmed in Bárðarbunga volcano, the volcano is under glacier so confirmation is difficult at best.

Earthquake activity in Bárðarbunga volcano. The two groups of earthquake swarms are visible on this map. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity has been dense as can be seen here. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor remains high on the Dyngjuháls SIL station. Why that is not clear at the moment. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor remains high at Vonarskarð SIL station. It has dropped little during the day, but it remains constant at current time. Copyright of this image belongs to Icelandic Met Office.

So far no major eruption has started in Bárðarbunga volcano. That might change without warning as this activity continues. There is a risk of large earthquakes taking place before such eruption. Since the crust in this part of Iceland is thick (up to 40 km thick) and last eruption in Bárðarbunga volcano took place in the year 1794. The eruption in the year 1910 took place in a volcano named Hamarinn and is south-west of Bárðarbunga volcano. Fissure eruptions are also a feature that Bárðarbunga volcano has, if this activity is going to result in such eruption is something that is impossible to know at current time.

Current status changes fast. I post new information on this activity as needed and as things get more clearer on what is happening.

August 16, 2014August 17, 2014

Short update Bárðarbunga volcano at 17:52 UTC

This is a short update on current status on Bárðarbunga volcano.

Uncertainty level has been declared on Bárðarbunga volcano and it status has been raised to yellow. There are fluxuation in earthquake activity, this is normal since earthquake activity in volcanoes is never close to constant in this type of situations. There is also a storm taking place in the area at the moment, that is lowering what is detected by the SIL stations that are close to Bárðarbunga volcano.

The earthquake activity in Bárðarbunga volcano. Green stars show earthquake larger than magnitude 3,0. Copyright of this image belongs to Icelandic Meteorological Office.

Largest earthquakes recorded so far have the magnitude of 3,1 and 3,5. There is a chance that more magnitude 3,0 have taken place but have not been reviewed yet by geologist at Icelandic Meteorological Office due the amount of earthquakes taking place at the moment.

As can be seen here the earthquake swarm is dense. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor in Dyngjuháls SIL station. It has been dropping in the past few hours. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor in Vonarskarð SIL station. The drop in harmonic tremor also appears clearly here. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor in Húsbóndi SIL station. The drop in harmonic tremor also appears here clearly. Copyright of this image belongs to Icelandic Meteorological Office.

In the past few hours the harmonic tremors around Bárðarbunga volcano have been dropping slowly. The drop in harmonic tremor has not been followed by drop in earthquake activity. At least that is not the case when this is written. This means that the magma that is on the move there still has not yet found a pathway to the surface, even if some small part of it has done so in possibly in one or two eruptions vents under the thick glacier. If the harmonic tremor stops completely without the earthquake activity stopping it means that magma is still on the move there and it might look for a new pathway to the surface. When and where that might happen is impossible to know at current time, but once the magma has clear path to the surface, even if it is under a glacier all earthquake activity is going to stop (for most part).

I am going to post more information when more details are available.

August 16, 2014August 17, 2014

Unconfirmed eruption in Bárðarbunga volcano

This information is going to get outdated quickly as more information is collected on this activity.

During all last week (Week 33) there has been a minor earthquake swarm in Bárðarbunga volcano. No other activity followed this minor earthquake activity during the week until last night (16-August-2014). During the night (around 02:20 UTC) a harmonic tremor started to appear on SIL stations around Bárðarbunga volcano. Following the appearance of the harmonic tremor earthquake activity started around 03:30 UTC. Largest earthquakes in this swarm have magnitude around 3,0 so far. Depth is around 5 to 10 km. During the night the earthquake swarm moved around in the volcano and is now more east then it first started. According to Rúv news the glacier around this part of Vatnajökull glacier is around 700 meters thick, so it going to take a major eruption to break the ice. This however also means that when a glacier flood starts in this area there is a high risk that is going to be large.

The largest earthquake that I did record during the night. This image is released under CC Licence. Please see CC Licence page for more details.

The earthquake swarm in Bárðarbunga volcano at 11:45 UTC. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor on Dyngjuháls SIL station. This SIL stations is closest to the area of activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor on Vonaskarð SIL station. This is one of the SIL station that is closest to the area of activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Currently the activity in Bárðabunga volcano is not stable, it does fluctuate a little. Besides this minor fluctuation it seems stable. Based on harmonic tremor signal and its range this does not appear to be a large eruption so far. That might change without warning. I do however expect larger earthquakes before any major volcano eruption in Bárðarbunga volcano. What seems to have happened is that a dike intrusion got to the surface and started this eruption, even if it is just small one at current time.

I am going to post update soon as more information gets available. This situation is going to change quickly and without much warning.

August 15, 2014

Earthquake swarm in Hveravellir

Two days ago (13-August-2014) an minor earthquake swarm took place in Hvervellir (volcano). Largest earthquake in this swarm had the magnitude of 2,5. All the earthquakes that happened had depth less then of 10 km.

Earthquake swarm in Hveravellir (blue dots). Copyright of this image belongs to Icelandic Meteorological Office.

Earthquake activity is fairly common in this area. It however works in a short activity periods with long quiet period between them. So far nothing suggest that major earthquake activity is going to take place there, as has happened in the past. If that happens, the largest earthquakes can go up to magnitude 5,0.

August 12, 2014August 13, 2014

Intra-plate earthquakes in north west Iceland

During the night of 12-August-2014 several intra-plate earthquake took place in north west Iceland. Largest earthquake in this swarm had the magnitude of 1,5. This earthquake activity did appear poorly on my geophone in Böðvarshólar. That is due to distance and small magnitude of the earthquakes, but my geophone at Böðvarshólar did detected this earthquake activity and from that I know that more earthquake activity took place than appears on Icelandic Meteorological Office maps.

The earthquakes in north west Iceland (yellow). This are intra-plate earthquakes. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake activity is not connected to any known fault zone or any known faults. That however does not mean they are not there. It is impossible to know if there is going to be more earthquake activity in this region. This is however second time this year a earthquake swarm takes place in this area, last one took place in week 28 (in Icelandic). That week the largest earthquake had the magnitude of 1,6.

August 12, 2014

Minor earthquake swarm in Krísuvík volcano

Yesterday (11-August-2014) a minor earthquake swarm took place in Krísuvík volcano. The largest earthquake in this minor earthquake swarm had the magnitude of 3,4 with the depth of 4,4 km. Only few minor earthquakes took place after the largest earthquake.

The earthquake swarm in Krísuvík volcano, the green star shows the location of the magnitude 3,4 earthquake. Copyright of this image belongs to Icelandic Meteorological Office.

There is a risk of more earthquake activity in this area. Since earthquake swarms are known to start with minor activity that slowly grows until it tops and then slowly drops over a period of days or weeks. It might not happen now, but this is a common pattern on the Reykjanes.

July 31, 2014

Minor earthquake swarm in Torfajökull volcano

Today (31-July-2014) a minor earthquake swarm took place in Torfajökull volcano. This was a minor earthquake swarm and no earthquake did go above magnitude 3,0. Strongest magnitude of this earthquake swarm had the magnitude of 2,3. Depth of this earthquake swarm was from 15,1 km to around 1,0 km.

The earthquake swarm in Torfajökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake swarm appears to be over, at least at the moment. It might start again at later time. Earthquake activity is common in Torfajökull volcano and there are no signs of any other activity from Torfajökull volcano at the moment.

July 15, 2014

Earthquake swarm in Katla volcano

Few days ago the uncertainty level around glacier rivers that come from Mýrdalsjökull glacier have been cancelled. However the area remains dangerous due to gases that might collect in pockets in low lying areas. So it is not safe to go close to the glacier rivers from Mýrdalsjökull glacier even if the uncertainty level has been cancelled by the authorities.

Earthquake activity today in Katla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Today (15-July-2014) an earthquake swarm took place in Katla volcano. Largest earthquake in this swarm had the magnitude of 3,1. Other earthquake that happened where smaller. This earthquake swarm is one of the most dense in the past few weeks and it appears that earthquake activity is once again on the rise in Katla volcano. I am now expecting this earthquake activity to continue. I also think there is a high risk of small eruptions within the Katla volcano caldera. This eruptions would only last for few hours at the most and not even break trough the Mýrdalsjökull glacier. It has to be noted that scientist on duty at Icelandic Meteorology Office does not agree with my opinion. While there is a high risk of this (in my opinion) that this might happen, it does not mean it is going to do so. The best thing that can be done for now is to observe activity in Katla volcano.

If anything more happens. I am going to post update on it soon as possible. Any large earthquakes that happen in Katla volcano do appear clearly on my geophone at Heklubyggð and they can be viewed here. There is also a web camera of Katla / Eyjafjallajökull located here.

July 9, 2014July 9, 2014

Uncertainty level declared at Katla volcano

Today (8-July-2014) a uncertainty level was declared at Katla volcano. This means that people should be aware of the activity that is now taking place in Katla volcano. The most dangerous areas at the moment are the glacier rivers that come from Katla volcano, due the extremely dangerous gases that are in the water coming from Mýrdalsjökull glacier. People should not stop at Múlakvísl glacier river and other glacier rivers that come from Mýrdalsjökull glacier due to this danger. It is also unclear if an larger glacier flood might take place, if it does it is going to happen with no warning at all. Tourist in the area also urged to have there mobile phones turned on in case emergency SMS needs to be sent to people in the area around Mýrdalsjökull glacier.

Earthquake activity in Katla volcano during the past 24 hours. Copyright of this image belongs to Icelandic Meteorological Office.

Currently [when I write this text] there is little earthquake activity in Katla volcano. That calm might not last, since earthquake activity has had the pattern of dropping off for few hours between peaks in activity. The largest earthquake during the past 24 hours had the magnitude of 3,0. Smaller earthquakes had the magnitude of 2,7 and lower magnitudes.

The magnitude 3,0 earthquake in Katla volcano this morning at 09:18 UTC. This image is released under Creative Commons licence. Please see CC Licence page for more details.

Earthquake activity has been in the same pattern as did happen in July-2011. So far no harmonic tremor has been detected. It is impossible to know if this is going to result in a eruption or not. The risk of an eruption is higher now then normal, but that does not mean that a eruption is going to take place. It is possible to see larger earthquakes from Katla volcano here on my webicorder website. It is possible to see Katla volcano here if it is not too cloudy.

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