Harmonic tremors – Page 16

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 This information might get outdated quickly as things change.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 Since midnight the total earthquake count for Iceland has now reached 578 (at 18:14 UTC) this number gets outdated quickly due the continuous earthquake activity in Bárðarbunga volcano.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 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.

July 23, 2014July 23, 2014

All traffic to Askja volcano forbidden due to a large landside yesterday (22-July-2014)

According to Icelandic Meteorological Office, a large landslide fell yesterday (22-July-2014) around midnight in Askja volcano, the landslide did go into Askja lake creating a flood wave that was 100 to 200 meters high. It did reach the other end of the crater lake and did flow over its edge, some water did go into Víti crater. This landslide took place in south part of the Askja lake crater (best information I have at the moment). Harmonic tremor was detected following this events, it was recorded for 20 minutes according to news reports (no image since Askja harmonic tremor plot image is missing in IMO website).

A cloud was seen following this landslide, it is not clear if it was steam or just loose dirt material moving up into the air. Early estimates into this landslide are that around 24 million cubic meters of material did come down with this landslide, part of it ending in Askja lake and raising the water levels in Askja lake some two meters (early estimates). Until this matter has been checked by scientist and Almannavarnir in Iceland, all traffic to Askja volcano is forbidden. There is also a risk of more landslides taking place in Askja volcano, since the soil where the landslide took place might not have settled yet. It is highly dangerous to go there under the current conditions and I urge anyone not to go there due to how dangerous this area now is.

Update 1: Image of the landslide can be found here.

I am going to post more information about this once I have more details on this event.

Icelandic news on this

Öll umferð bönnuð um Öskju eftir gríðarlega stóra skriðu (DV.is)
Umferð um Öskju bönnuð eftir stóra skriðu (Rúv.is)
Stór skriða féll í Öskjuvatn (Mbl.is)

Donations: Please remember to donate. While I am going to move back to Iceland in December. I still have to make it until then (somehow). Thanks for the support.

Article updated at 00:34 UTC on 23-July-2014.

March 28, 2014March 28, 2014

Earthquake swarm in Grímsfjall volcano

Today (27-March-2014) an earthquake swarm took place in Grímsfjall volcano. This activity is connected to current minor glacier flood from Grímsvötn glacier lake that is now taking place. The glacier flood it self is an minor and is about the same size as an glacier flood from Grímsvötn glacier lake in November-2012.

Earthquake activity in Grímsfjall volcano today (27-March-2014). Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor has been increasing in Grímsfjall volcano following this glacier flood. The leading idea is that the glacier flood is creating this high frequency harmonic tremors. This idea however remains unconfirmed at current time.

Harmonic tremor at 21:13 UTC on 27-March-2013 at Grímsfjall volcano. The harmonic tremor starts at the end of this plot. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor at 22:55 UTC on 27-March-2014. As can be seen the high (blue line) harmonic tremor is increasing at the moment. Copyright of this image belongs to Icelandic Meteorological Office.

At present time there is nothing to suggest that an eruption has or is about to start in Grímsfjall volcano. However Grímsfjall volcano is unpredictable and highly active when it comes to eruptions. If an eruption starts in Grímsfjall volcano it might do so without an warning. Earthquake activity in Grímsfjall volcano would increase sharply just before the eruption would start as was the case before the eruption in 2011 (covered here). More detailed monitoring can of Grímsfjall volcano and other volcanoes in Vatnajökull glacier can be found here (Icelandic).

Advertisement: As I did say few days ago. I am adding advertisement back to my websites. Since I need to eat and pay the bills. There however has been a minor issue with my Google Adsense account. An issue that has so far not yet been resolved by Google. Once its resolved I am going to go trough the process of getting my account approved again. I was too detailed back in January when I closed down my Google Adsense account. I hope to have advertisements back before some volcano erupts in Iceland.

November 27, 2013November 27, 2013

Harmonic tremor detected in Þórðarhyrna volcano

On the 21-November-2013 there was an earthquake swarm in Þórðarhyrna volcano (part of Grímsfjall volcano). This was not large earthquake swarm or a strong one. With the largest earthquake just having the magnitude of 1,9. While I did just suspect it I did not have it confirmed until today that following this earthquake swarm was an harmonic tremor pulse. This harmonic tremor lasted from 03:30 to 06:10 UTC. Based on nearby SIL station this was not a strong harmonic tremor, but this is important because it suggests that something is taking place in Þórðarhyrna volcano. If this is going to lead to an eruption is unknown at current time. This might be a dike intrusion into the volcano at depth, but that has not been confirmed.

The harmonic tremor pulse can be seen at 21-November date on this tremor plot from Icelandic Meteorological Office. Copyright of this image belongs to Icelandic Meteorological Office.

The harmonic tremor pulse as it did appear from Grímsfjall SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor pulse as it did appear on Jökulsel SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

This activity might not lead to an eruption, but given the past history of this area and the eruption in Grímsfjall volcano in the spring of 2011 I find it to be highly likely outcome that eruption is going to take place in Þórðarhyrna volcano in near future, it is not possible to know when such eruption might take place. Last eruption took place in Þórðarhyrna volcano in the year 1902, it is not known if any later eruptions have taken place in Þórðarhyrna volcano.

Blog post updated at 14:47 UTC.

September 3, 2013September 3, 2013

Minor dike intrusion into Bárðarbunga – Hamarinn volcanoes

It seems that yesterday (02-September-2013) a minor dike intrusion took place in Bárðarbunga – Hamarinn volcanoes. This created an minor harmonic tremor yesterday on nearby sil stations. There were earthquakes following this events, the strongest one had the magnitude of 2.8 at the depth of 14 km. A second earthquake with the magnitude of 2.1 took place few moments later, it had the depth of 15.5 km. Only one smaller earthquake have seen taken place in this area of Bárðarbunga – Hamarinn volcanoes.

The earthquake activity in Báðarbunga – Hamarinn volcano area. Copyright of this image belongs to Icelandic Meteorological Office.

It is important to notice that dike intrusions are common in this area, often happen many times a year. How many takes place can vary between years. That dike intrusion took place does not mean an eruption is going to take place. It just means that magma moved, what that means for the future is unknown at present time.

Donations: It would be nice if people donated so that I can buy food this month. In other case I am going to have to eat really little this month and I am not happy about such things taking place.

Blog post updated at 21:43 UTC on 3-September-2013.

September 3, 2013September 3, 2013

Interesting harmonic signals appearing around Vatnajökull glacier

In the past few hours an interesting harmonic signals have been taking place on two sil stations (so far) around Vatnajökull glacier. I do not know what is creating this harmonic tremor spikes on them, it might be water on the move or starting to move from Skaftár cauldron in Vatnajökull glacier or it might be something different that I do not know about at present time. Currently the source of this harmonic tremor is unknown and it might never been known in the worst case. I do hope to figure out in next few hours what is creating this harmonic tremor spikes on this two sil stations.

The harmonic tremor signal at Skrokkalda sil station. The harmonic tremor signal can be found at the end of the tremor plot. Copyright of this image belongs to Icelandic Meteorological Office.

The harmonic tremor signal at Jökulsel sil station. It is at the end of the tremor plot. Copyright of this image belongs to Icelandic Meteorological Office.

As I say above, the source of this tremor signal is not known. It might be bad weather in the area, traffic (unlikely due to bad weather in this part of Iceland at the moment) or something that is not known at the moment. What I can rule out at the moment is this harmonic tremor signal does not appear to come from magma movement, the frequency of the harmonic tremor is too high for that at the moment and does not show little to no energy at 0.5 to 1 Hz band. This suggest the source is something else then magma, this however does not rule out magma. Since magma is known to due many strange things under pressure and high frequency harmonic tremors are not unknown, but they are unlikely to take place rather than being a common feature in volcano activity.

For the moment the best thing that can be done is to monitor the signal and see if there are any changes and on the nearby sil stations. For the moment I do not expect any major change in this area, risk of glacier flood is still in place for this part of Vatnajökull glacier. If this harmonic tremor signal connects to that is not known at the moment.

September 2, 2013

Possible glacier flood from Skaftár cauldron

It is possible that glacier flood from Skaftákötlum cauldron has started some hours ago. According to Rúv, Icelandic Meteorological Office is now monitoring for signs that glacier flood has started. Changes in conductivity in glacier rives from Vatnajökull glacier (South-West) and the rivers that normally flood from Skaftárkötlum cauldron. It has not been confirmed that glacier flood has started yet.

At the moment it has not been confirmed that glacier flood has started, but it might start soon. I am going to post more information once I have them or when they are published.

Icelandic News about this

Fylgjast náið með Skaftárhlaupi (Rúv.is)

January 17, 2013

Comparison of volcano eruptions

When there is nothing going on in Iceland. It is good to prepare for the future by checking out what has happened in the past. Here is a comparison of harmonic tremor data from few past eruptions. I only have limited set of data to work with here.

Grímsfjall volcano eruptions 2004 and 2011

Harmonic tremor indicates how strong the eruption is when it is happening. This is clearly visible on the harmonic tremor plots from the Grímsfjall volcano eruptions in the year 2004 and compared to the eruption in Grímsfjall volcano eruption in the year 2011.

Harmonic tremor in Grímsfjall volcano eruption in the year 2004. Copyright of this image belongs to Icelandic Meteorological Office.

This harmonic tremor plot is from the early start of the eruption. It clearly shows when the eruption starts and how it progressed during it’s first few hours.

Here is the volcano eruption start in Grímsfjall volcano on 23. May 2011. This is the start of the eruption. It clearly shows the difference from the eruption that took place in the year 2004. Both is that starts sharper. But is also a lot more powerful then the eruption in the year 2004. Copyright of this image belongs to Icelandic Meteorological Office.

Eyjafjallajökull volcano and Katla volcano

Sometimes it is useful to compare two eruptions of two different volcanoes. This is useful when you really don’t have anything else to compare with.

Harmonic tremor in Eyjafjallajökull volcano eruption back in the year 2010. This is from the second phase of the eruption. But I seems to have misplaced or not saved harmonic tremor data from the first phase of the eruption (at least I cannot find them for the moment). Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor connected to a minor eruption in Katla volcano in July 2011. This eruption was minor. But created a flood that took out a bridge. Copyright of this image belongs to Icelandic Meteorological Office.

Diffrent SIL stations from the same minor eruption in Katla volcano in July 2011. This clearly shows that this minor eruption in Katla volcano was possibly larger then eruption in Eyjafjallajökull volcano year earlier (2010). But it did not manage to break the ice of Mýrdalsjökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

Past data show and are useful to learn what happens in a volcano. For this reason I now save important information on what is happening in a volcano. So I can compare it with future activity when it takes place.

Cookie acceptance