Category: Monitoring

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Interesting earthquake swarm in TFZ

Today (12.12.2012) there was a interesting earthquake swarm in south part of TFZ (close to a place called Ásbyrgi). This earthquake swarm did consist mostly of minor earthquakes. With magnitudes of from ML0.2 and up to magnitude ML2.6. This earthquake swarm is tectonic in nature. I do not believe it is volcanic in nature. But this earthquake swarm is inside Krafla volcano fissure swarm or TFZ-NVZ two volcanoes. I am not sure in this case here.


The earthquake swarm is in the corner of this image. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake swarm might not mean anything special as is. But earthquake activity in this area has been some for the past few years. But it has so far never resulted in any major events so far in this area.

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Harmonic tremor level drops in Grímsfjall volcano

During the night. Harmonic tremor levels started to drop in Grímsfjall volcano. The reason for this harmonic tremor level increase remain unknown and unclear. But no volcano related activity has been seen or recorded so far in Grímsfjall volcano.


Harmonic tremor levels in Grímsfjall volcano. This is high resolution image. Copyright of this image belongs to Icelandic Meteorological Office.


Harmonic tremor levels in Grímsfjall volcano. This is low resolution image. Copyright of this image belongs to Icelandic Meteorological Office.

Some earthquake activity has been taking place following this events. But the earthquakes have been small and do not suggest anything is about to take place in Grímsfjall volcano.


Earthquake activity in Grímsfjall volcano for the past 48 hours. Copyright of this image belongs to Icelandic Meteorological Office.

So far Grímsfjall volcano has remained quiet during this glacier flood. With nothing suggesting that it is going to change soon. As for the glacier flood it self. According to latest news it seems to have peaked and is now dropping. But this was a small glacier flood. With just rise about 153 cm. But that is quite small compared to many older glacier floods from Grímsfjall volcano.

Icelandic News about this glacier flood

Hlaupið í Grímsvötnum virðist hafa náð hámarki (Vísir.is)
Hlaupið í Gígjukvísl í rénun (Rúv.is)

Blog post updated at 12:48 UTC on 27.11.2012

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Minor glacier flood has started from Grímsfjall volcano glacier lake

A minor glacier flood has started from Grímsfjall volcano glacier lake. This glacier flood is expected to be extremely small. Since last glacier flood from Grímsfjall volcano took place earlier this year. That glacier flood was also small. Minor harmonic tremor changes have been taking place on Grímsfjall SIL stations. But they are not strong and can easily drown in wind noise. But it has been a stormy few weeks in Iceland.


Harmonic tremor changes on Grímsfjall SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

I do not expect any volcano activity to take place following this glacier flood. As last eruption in Grímsfjall volcano took place last year and that eruption was the largest one in 140 years at least. But I am going to keep monitoring this activity and post updates if anything changes.

Icelandic News about this glacier flood

Lítið hlaup hafið í Grímsvötnum (Rúv.is)
Vatnamælingamenn á leið austur (Rúv.is)
Hlaup að hefjast í Grímsvötnum (Vísir.is)
Lítið hlaup hafið í Grímsvötnum (mbl.is)

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Earthquake swarm in TFZ continues, little earthquake activity in Katla voclano, new earthquake activity in Askja volcano

Here is a short update on activity in Iceland for the past few days.

Tjörnes Fracture Zone

Earthquake activity continues in Tjörnes Fracture Zone. But this earthquake activity has been ongoing since 20 October, 2012. Every once in a while a magnitude 3.0 earthquake takes place, or larger. The risk of large earthquake taking place in this area remains. General alert for this area is also in effect because of this danger of large earthquake taking place in this area.


The earthquake activity in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

Katla volcano

Winter has come. At least when it comes to earthquake activity in Katla volcano. But little to none earthquake activity is now taking place in Katla volcano. Earthquake activity is now well below background level. It can be expected that current status is going to remain in Katla volcano until next summer.


Earthquake activity in Katla volcano for the past few days. Nothing important is taking place in Katla volcano as this image clearly shows. Copyright of this image belongs to Icelandic Meteorological Office.

Askja volcano

While Katla volcano is getting quiet. It seems that Askja volcano is getting slightly more active. But earthquake activity in Askja volcano during the past few weeks suggests a minor magma intrusion (dike intrusion) might have taken place. But none of the earthquakes that took place where above magnitude 2.0 in size.


Earthquakes in Askja volcano during the past few days. Copyright of this image belongs to Icelandic Meteorological Office.

I do not think this earthquake activity in Askja volcano means it is getting close for an eruption. Since there are no signs in that direction at the moment. But this earthquake activity is interesting. What ever it means in the short term for Askja volcano. It is also common that volcanoes have earthquake activity without anything happening at all following such earthquake activity.

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Earthquake activity update for Iceland and TFZ

This is update for TFZ over the past few days. Along with update for earthquake activity in Iceland during the past few days.

Tjörnes Fracture Zone

Earthquake swarm in TFZ continues. In the past days the largest earthquakes have had the magnitude of ML3.2. A second earthquake swarm is also taking place west of the village of Kópasker. That area also had an earthquake with the magnitude of ML3.2. That earthquake swarm is unrelated to the earthquake swarm taking place off north of Siglufjörður village. Earlier today an earthquake with the magnitude 3.8 took place. More earthquakes are expected to take place. This latest earthquake was clearly felt in Siglufjörður village. This earthquake swarm started on 20th of October. So it has been ongoing now for almost two weeks.


The latest earthquake in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.


Earthquake tracker from Icelandic Meteorological Office showing the earthquakes during the past 48 hours in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquake activity is expected to continue in this part of TFZ. The risk of large earthquake in this area has not yet passed. Most of the earthquakes appears clearly on my geophone in Hvammstangi.

Iceland activity

Other the earthquake activity in TFZ. It has been generally quiet in Iceland. For the past four days there has been really bad winter storm taking place in Iceland. With wind up to 40m/s and wind gust up to 70m/s or more. This means that fewer earthquakes are being detected by the SIL network in Iceland due to increased wind noise. But earthquake activity has been low in Iceland for the past few weeks (besides TFZ). So I am not sure if that changes anything. There is no volcano activity taking place in Iceland at the moment.

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Uncertainty level is declared in north Iceland due to risk of large earthquake from TFZ

Uncertainty level has been declared in north Iceland due to risk of large earthquake taking place in TFZ. This is done after consulting scientists that have been monitoring this area for the past few days since the earthquake swarm started in TFZ. It is still impossible to know when a large earthquake might take place in TFZ. But the earthquake swarm is still ongoing with little change.

The Civil Protection of Iceland announcement

Óvissustigi almannavarna lýst yfir vegna jarðskjálftahrinu úti fyrir Norðurlandi (Icelandic)

Icelandic news about this

Óvissustigi almannavarna lýst yfir (Rúv.is)
Lýsa yfir óvissustigi almannavarna vegna jarðskjálftahrinu (mbl.is)

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Earthquake swarm update for TFZ and Kverkfjöll volcano at 12:55 UTC

Earthquake swarm in TFZ continues. But earthquake activity continues to drop at fast rate. The largest earthquake so far from midnight has the magnitude of 4.0 (reviewed magnitude). Several smaller earthquakes have taken place during the night in TFZ. But no larger earthquakes have so far taken since midnight. Current earthquake activity has moved little bit east since it started on 21.10.2012.


Current earthquake activity in TFZ for the past few months. Copyright of this image belongs to Icelandic Meteorological Office.

Kverkfjöll volcano

Earthquake activity has continues since it started again in Kverkfjöll volcano. The strongest earthquake so far had the magnitude 3.3. This earthquake activity in Kverkfjöll volcano has it source in magma movements inside Kverkfjöll volcano. This is most likely not going to start an eruption. But it is worth keeping an eye on.


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

Earthquake activity has been slow in Kverkfjöll volcano. This is normal. As this is not tectonic movements, as in TFZ. But magma often moves slower and makes fewer earthquakes then just pure tectonic movements.

Blog post updated at 14:06 UTC on 23.10.2012
Blog post updated at 14:14 UTC on 23.10.2012

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New earthquake swarm in Kverkfjöll volcano

It seems that earthquake activity has started again in Kverkfjöll volcano. So far this is just small earthquakes. But earthquake activity started in Kverkfjöll volcano on 20.10.2012. That was also just small earthquakes. This is most likely minor dike intrusion taking place in Kverkfjöll volcano.


Earthquake in Kverkfjöll volcano. Copyright of this image belongs to Icelandic Meteorological Office.

It is impossible to know what this activity means. But I do think it is going to remain as is for now. At least it is unlikely for the time being that something bigger is going to happen in Kverkfjöll volcano. But it is worth keeping an eye on this activity. As this might be a clue that Kverkfjöll volcano are waking up from there dormancy. But it might just be minor earthquake activity that happens occasionally in volcanoes, without any other activity taking place in them following such activity.

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TFZ earthquake swarm update at 11:03 UTC on 22.10.2012

The earthquake swarm in TFZ continues at slowed rate then before. But number of earthquakes has dropped more then half since yesterday. During the night the strongest earthquake was ML4.1. With several earthquakes with the magnitude of 3.0 to 3.9. Many smaller earthquakes have taken place. Most of them with the magnitude around 2.0.


The area of earthquake activity in TFZ. The green stars mark earthquakes that where larger then ML3.0. Copyright of this image belongs to Icelandic Meteorological Office.


Trace showing the earthquake activity in TFZ during past 48 hours. Copyright of this image belongs to Icelandic Meteorological Office.


Tremor plot showing the earthquake activity. This is Hraun á Skaga SIL station. Copyright of this image belongs to Icelandic Meteorological Office.


Tremor plot showing the earthquake activity. This is Siglufjörður SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquake activity is currently ongoing and is not expected to stop any time soon. But it might slowly decrease if there are no large earthquakes in this area in next few hours to days. But there is always more earthquake activity following stronger earthquakes in this area. The largest earthquakes in this earthquake swarm have been felt in the town of Siglufjörður and at times in other nearby towns in the area.

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Earthquake traces of the magnitude Mw5.6 earthquake

Here are the earthquake traces of the magnitude Mw5.6 earthquake that took place in TFZ on 21.10.2012 at 01:24 UTC. I did detect this earthquake in all of my geophone stations in Iceland.


The Mw5.6 earthquake in TFZ. This is the Z trace. This image is released under Creative Commons licence. See licence page for more details.


The Mw5.6 earthquake in TFZ. This is the E-W trace. This image is released under Creative Commons licence. See licence page for more details.


The Mw5.6 earthquake in TFZ. This is the N-S trace. This image is released under Creative Commons licence. See licence page for more details.

The interesting thing about this earthquake is how stronger the N-S,E-W trace is compared to the Z (vertical). This shows that this earthquake movement was strongest on E-W and N-S then vertical (Z).


The Mw5.6 earthquake in TFZ. This is Heklubyggð geophone station. This image is released under Creative Commons licence. See licence page for more details.


The Mw5.6 earthquake in TFZ. This is Eyrarbakki geophone station. This image is released under Creative Commons licence. See licence page for more details.


The Mw5.6 earthquake in TFZ. This is Skeiðflöt geohone station. This image is released under Creative Commons licence. See licence page for more details.

Earthquake activity is currently ongoing in TFZ. With earthquakes often reaching magnitude 3.0 in size. But many smaller earthquakes have taken place in the past 10 hours in TFZ. But overall the earthquake activity has slowly been dropping down since the large Mw5.6 took place at 01:24 UTC. If the earthquake activity is going to increase again is impossible to know for sure at current time.