Category: Dyke intrusions

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More earthquake activity in Tjörnes Fracture Zone

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Today (01-October-2013) there has been a lot of earthquake activity in Tjörnes Fracture Zone. Current area of activity is same as for the past week, what is now changing is the rate and magnitude of earthquakes. This morning an magnitude 3.2 earthquake took place in this area. That earthquake and at least two other smaller ones where felt in Ólafsfirði, the town closest to this earthquake swarm. Earthquake activity is currently ongoing and with no signs of stopping.

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

It has been reported by Rúv and other news media in Iceland that this might be an dike intrusion in this area. This is what geologist at Icelandic Meteorological Office are theorising at the moment. I do not know if this is true or not. What I do know is that at this location there is no known volcano and if there is an volcano at this location it is currently unknown and not documented at all (such things happen). If this is magma and if it finds an path to the surface we are going to see an eruption. I do not know if that would create an new island if that was the case, such speculations have to wait until an eruption started. If it ever gets that far. If this is magma then it is still at great depth, since the depth of this earthquake swarm is at the moment around 5 to 15 km and does not seem to change that much at the moment.

It is possible to watch this earthquake activity here on my webicorder website. The closest geophone station that I have to this earthquake swarm is the one named “Böðvarshólar”. It is already showing many of the strongest earthquakes in this swarm clearly. It is located in the country side far from any major traffic source.

I am going to post updates about this earthquake swarm when needed.

Blog post updated at 20:26 UTC on 01-October-2013.
Blog post updated at 23:53 UTC on 01-October-2013.

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Minor earthquake swarm in Esjufjöll volcano

Today (05-September-2013) an minor earthquake swarm took place in Esjufjöll volcano. Largest earthquake in this swarm had the magnitude of 2.2 and the depth of 4.9 km.

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Earthquake swarm in Esjufjöll volcano. Esjufjöll volcano are located in south part of Vatnajökull glacier, just northeast of Öræfajökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquakes in this area are because of magma movement it is believed. Now there are more SIL stations in the area, so more earthquakes are being recorded. Few years ago the lowest magnitude that Icelandic Meteorological Office was able to detect in Esjufjöll volcano was magnitude 1.5 and above.

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Earthquake activity in several volcanoes

Today (04-September-2013) had some minor earthquake activity in several volcanoes in Vatnajökull glacier. All of this earthquakes were small and less than magnitude 3.0 in size.

Kverkfjöll volcano

The deepest earthquake activity was in Kverkfjöll, with earthquakes at 31 km depth and 24 km depth. This deep earthquake activity is possible connected to magma movements since tectonic earthquakes are unlikely to take place this deep in the crust.

Grímsfjall volcano

One earthquake was recorded in Grímsfjall volcano, it was minor and shallow. This might even just be a glacier quake, rather than normal earthquake.

Öræfajökull volcano

Öræfajökull volcano did see two earthquake today, at the depth of 4 to 5 km. Both were small and tectonic in nature from the looks of it. Earthquakes are not common in Öræfajökull volcano so I am not sure why this increase has now taken place. It is worth noticing that sil network is now more sensitive in this area than before since new stations have been added in this area. This means that smaller earthquakes are now being detected than before.

Esjufjöll volcano

Esjufjöll volcano had two earthquake, the third earthquake might be a ice-quake. I am not sure if it was an real earthquake or not. Esjufjöll volcano normally do not have any earthquake activity, but few years ago an earthquake activity started with earthquakes that had magnitude of 2.5 to 3.0 so there is something going on in this volcano. What that might be I am not sure of yet.

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Earthquake activity in Kverkfjöll, Öræfajökull, Esjufjöll, Grímsfjall volcanoes. All small earthquakes. Copyright of this image belongs to Icelandic Meteorological Office.

I do not expect anything major to take place in Vatnajökull volcano. Since the current quiet period in Iceland just seems to be ongoing as is.

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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.

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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.

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

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Minor earthquake swarm in Katla volcano

Today (21-June-2013) there was an earthquake swarm in Katla volcano, this earthquake swarm took place in the same area where the minor eruption in the year 2011 (July) took place and created a minor glacier flood down Múlakvísl river. So far there is nothing that suggest a eruption is about to take place in Katla volcano, this activity needs to be monitored closely since things can change quickly in Katla volcano.

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Earthquake activity in Katla volcano on 21-June-2013. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake activity in Katla volcano starts around the same time as it did two years ago (2011), but then earthquake activity started on 17-June-2011 and continued until July-2011 and did not end until November-2011. This type of earthquake activity did also take place in June-2012, but no eruption did take place that summer. I expect this earthquake activity to continue in Katla volcano for the time being, sine most earthquake activity always happens during the summer in Katla volcano. It is unclear that is creating this earthquake swarm, it can be anything from pressure changes in hydro-thermal zones in this area, or magma injections at depth, I do not think any dike intrusions have taken place so far in Katla volcano.

Currently there is nothing that suggests eruption is going to take place soon in Katla volcano.

Blog post updated at 22:06 UTC on 21-June-2013.

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Fresh dike intrusion into Bárðarbunga volcano

Interesting earthquake activity continues in Bárðarbunga volcano. There is also interesting earthquake activity taking place in Hamarinn volcano. The source of this activity is magma dike activity in Bárðarbunga volcano. It is most likely not going to result in a eruption, but might be a sign of more activity in the future.

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Activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Meteorological Office.

There has also been activity in Hamarinn volcano, I do not know if it is connected with the activity in Bárðarbunga volcano. I find it unlikely to be the case, but I cannot rule it out at current time. It is unclear if this is new earthquake activity, it might be as simple as new SIL stations in the area, or this could be real activity increase in the area close to Hamarinn volcano. I am currently not clear on this detail as is. Last eruption in Hamarinn volcano was in July 2011, I did write about it here. It is worth keeping a eye on this activity in the Hamarinn volcano, it has proven to be a unpredictable volcano and it appears that magma is at shallow depth in it.

Blog post updated at 23:32 UTC on 20-June-2013.

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Minor earthquakes in Katla and Bárðarbunga volcanoes

There has been minor earthquake activity in Bárðarbunga volcano and Katla volcano for the past few days. This is just a short overview of this earthquake activity.

Bárðarbunga volcano

A minor dike intrusion took place in Bárðarbunga volcano on 18-June-2013. This was a small earthquake swarm, with largest magnitude at 1.2, the most depth in this earthquake swarm was at 24.3 km. So this was most likely a magma dike formation.

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The magma dike earthquakes form a nice line on this IMO map. Copyright of this image belongs to Icelandic Meteorological Office.

Katla volcano

A minor earthquake activity has been taking place in Katla volcano for the past few days. So far it does not mean anything, this is most likely a summer related earthquake activity as glacier weight gets less on Katla volcano during the summer. Some deep earthquakes have been taking place in Katla volcano, it is unclear if they are sign of anything at this stage. This is most likely a some magma dike intrusion at depth, it happens commonly in Katla volcano without resulting in a eruption.

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Activity in Katla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Other then minor activity, it is rather quiet in Iceland at the moment. With no special activity taking place currently.

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Earthquake activity in Hekla, Katla, Krísuvík and Bárðarbunga volcanoes

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Hekla and Katla volcanoes

I am going to write about both this volcanoes here. Since I am going to be using the same image anyway for both volcanoes.

Yesterday (26.04.2013) there was a magnitude 1.1 earthquake in Hekla voclano. This earthquake was in the same area that triggered uncertainty level to be declared just before Easters in March. It was later cancelled when nothing more happened.

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Earthquake in Hekla volcano. Also on this picture earthquake activity in Katla volcano (read more below). Copyright of this picture belongs to Icelandic Meteorological Office.

Katla volcano has been having some earthquake activity in past days. So far it has just been minor earthquakes and nothing more. But it has been taking place where a minor eruption took place in Katla volcano during the summer of 2011. That minor eruption created a minor glacier flood. But it did destroy a bridge and closed down the ring road (road 1) in this part of Iceland.

While this activity is currently nothing to worry about. It is worth keeping a eye on it. Just in case it increases, or if some other changes start to take place in Katla volcano.

Krísuvík volcano

A minor earthquake swarm took place in Krísuvík volcano today (27.04.2013). The largest earthquake had the magnitude of 1.9. The depth of this earthquakes was around 8.6 km. Activity in this area is normal and there does not seem anything strange about it. But Krísuvík volcano has been having periods of inflation and deflation for the past three years. Earthquake activity increases when Krísuvík volcano is in period of inflation. If that is the case now I do not know.

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Earthquake activity in Krísuvík volcano. Copyright of this picture belongs to Icelandic Meteorological Office.

Bárðarbunga volcano

A minor earthquake swarm took place in Bárðarbunga volcano today. Largest earthquake in this swarm had the magnitude of 1.3. Depth range was from 18.8 km and up to 11.1 km. This earthquake swarm is important. Since it appears that this is a dike intrusion in Bárðarbunga volcano. But a minor dike intrusion also took place in this area few weeks ago. That also resulted in a minor earthquake swarm in this same area.

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Earthquake activity in Bárðarbunga volcano. Most likely due to minor dike intrusion into the volcano. Copyright of this picture belongs to Icelandic Meteorological Office.

A minor dike intrusions into a volcano does not mean a eruption is going to take place. In many Icelandic volcanoes (and around the world also) dike intrusions into the volcanoes are common event and in most cases do not result in any eruptions. But it is worth keep a watch out for this type of eruptions. Since it might signal a more active period ahead in Bárðarbunga volcano. But it might also just equally don’t mean anything. There is no way to know for sure.

Other then this activity. It has been rather quiet in Iceland at the moment. No larger earthquakes have been taking place in the past two weeks since activity slowed down in Tjörnes Fracture Zone.

Blog post updated at 22:32 UTC on 27.04.2013.
Blog post updated at 22:53 UTC on 27.04.2013.

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Magnitude 3.6 earthquake in Hamarinn volcano

Last night (05.04.2013) at 01:50 UTC a magnitude 3.6 earthquake took place in Hamarinn volcano (no GVP profile yet!). This earthquake had the depth of 2.1 km. This seems to be a dike intrusion taking place in Hamarinn volcano. No clear signs of harmonic tremor have been detected based on tremor data from Icelandic Meteorological Office.

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The Hamarinn volcano is where the green star is. But that is the location of the magnitude 3.6 earthquake that took place last night. Copyright of this image belongs to Icelandic Meteorological Office.

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Harmonic tremor plot do not show any harmonic tremor pulse. The signal on this harmonic tremor plot is the earthquake swarm in TFZ for most parts. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake activity is due to minor dike intrusion. Rather then something else. It is not clear if this activity is just normal activity for Hamarinn volcano or signal about something else is about take place. But as before. Hamarinn volcano remains mostly quiet for the moment.

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Earthquake activity in Esjufjöll volcano

Earthquake activity has started again in Esjufjöll volcano after some time with no activity. The two earthquakes that where detected by the SIL network only had the magnitude of 1.0 and 1.1. But what is most interesting is there depth. But registered depth is around 0.1 km (around 100 meters). This really shallow depth for earthquakes in this location. While it is unclear what is creating this earthquake activity. The most likely reason is that an minor dike intrusion is taking place in the volcano. Last eruption in Esjufjöll volcano is believed to have taken place in the year 1920. But that has not been properly confirmed yet.

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Earthquake activity in Esjufjöll volcano is marked by the red dots in Vatnajökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

It is impossible to know for sure what is happening in Esjufjöll volcano. Not only is there little known about earlier eruption history of this volcano. It has also been poorly studied in the past. So what to expect if anything happens is not known properly. Based on earlier earthquake activity in this volcano from the year 2011 more earthquakes might happen in next few days to months. But it is impossible to know that for sure at the moment. But it is not an bad idea to monitor this volcano for any more activity in next few weeks.