Category: Swarm

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Earthquake swarm in Kverkfjöll volcano

At 20:03 UTC an earthquake swarm started in Kverkfjöll volcano. The strongest earthquake so far has the magnitude of ML2.6, the depth is 1.1 km according to automatic estimate. Both size and depth of this earthquake are expected to change once it has been reviewed by Icelandic Meteorological Office. So far no harmonic tremor has been detected following this earthquake swarm. The most likely explanation for this earthquake swarm is that dike intrusion of magma has started in Kverkfjöll volcano. This has been happening on regular basis now for several years.


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

The earthquake swarm is currently ongoing. It is hard to know what happens in Kverkfjöll volcano following this earthquake swarm. But Kverkfjöll volcano are among Iceland most active volcanoes. With last eruption being in the year 1968 (small I think). This is clearly magma on the move inside Kverkfjöll volcano. But I do not know if this is going to result in a eruption or not. At the moment. It is my estimate that eruption is unlikely to happen. But that might change without warning at any time. But changes in Kverkfjöll volcano might be rapid and without warning. I am going to continue to monitor this activity and post new blog post if there are any major changes in activity in Kverkfjöll volcano.

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Earthquake swarms in Brennisteinsfjöll volcano and TFZ

Over the past few days there has been continued earthquake activity in Breinnisteinsfjöll volcano. The largest earthquake in this swarm had the magnitude of ML2.5. It is possible that this earthquake swarms have there orgin in SISZ. Rather then Breinnisteinsfjöll volcano. But at current time is hard to be sure on this detail.


Earthquake activity in Breinnisteinsfjöll volcano during the past few days. Copyright of this image belongs to Icelandic Meteorological Office.

Tjörnes Fracture Zone

Earthquake activity has also been taking place east of Grímsey Island. This earthquake activity has mostly been small. But this are earthquake swarm did not have any earthquake that was above 3.0 in magnitude.


Earthquake swarm on TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

The largest earthquake in this swarm had the magnitude of ML2.8. More earthquake activity should be expected in this area. As this is one of most active areas in Iceland when it comes to earthquake swarm.

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Magnitude 3.8 earthquake in Breinnisteinsfjöll volcano

Earthquake with the magnitude of 3.8 took place in Breinnisteinsfjöll volcano at 19:42 UTC. This earthquake was felt in Reykjavík and nearby area. Many aftershocks have followed this earthquake. Most of them are however below 2.0 in magnitude. There was also pre-earthquake activity before the magnitude 3.8 earthquake did take place. Most of those earthquakes where below 2.0 in magnitude. Last month an earthquake with the magnitude 4.3 took place in this same area. Earthquake activity is currently ongoing with smaller earthquakes for the time being.


Green star marks the place where the magnitude 3.8 earthquake took place. Copyright of this image belongs to Icelandic meteorological Office.

So far there is nothing to suggests that current earthquake activity is nothing but tectonic. But this area is a riftzone. So there are earthquake swarm often take place there without them being related to any volcano activity in this area. This earthquake swarm appears clearly on my geophone network in Iceland. I am going to continue to monitor this earthquake activity. As more strong earthquakes in this area can take place in the next few hours to days.

Icelandic news about this earthquake activity

Jarðskjálfti upp á 3,8 í Bláfjöllum (Rúv.is)
Jarðskjálftar við Bláfjöll (mbl.is)
Jarðskjálfti í Bláfjöllum (Vísir.is)
Skjálftinn var 3,8 stig (mbl.is)

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Earthquake swarm east of Grímsey Island.

This morning a earthquake swarm started east of Grímsey Island. This is activity in TFZ area that possibly has two active volcanoes (GVP information). This is however most likely just a normal earthquake activity taking place now in this area of Iceland. The largest earthquake in this earthquake swarm was a magnitude 3.1 earthquake that took place at 11:35 UTC.


Earthquake swarm on TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake swarm might continue for the next few hours. With the possibility of more earthquakes reaching magnitude 3.0 or larger. But it is common for earthquakes swarms in this area to just stop over period of few hours. The largest earthquake in this earthquake swarm was not felt according to the news.

Icelandic news about this earthquake swarm

Jarðskjálfti norðan Grímseyjar (Rúv.is)
Jarðskjálftahrina við Grímsey (mbl.is)

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Magnitude 3.1 earthquake in Katla volcano this morning

Today at 08:26 UTC this morning a magnitude 3.1 earthquake took place in Katla volcano. There was minor pre-earthquake activity before the magnitude 3.1 earthquake took place, the depth of this earthquake was around 100 meters (0.1 km). There was also some minor aftershock activity following this earthquake. No change in harmonic tremor took place following this earthquake. So there is a good chance this was just part of normal autumn activity in Katla volcano. This earthquake activity did appear clearly on my geophone network. It can be viewed here on my geophone network web page.


The earthquake as it did appear on my geophone station in Skeiðflöt. This image is released under Creative Commons licence. See CC licence page for more details.


The earthquake as it did appear on my geophone station in Heklubyggð. This image is released under Creative Commons licence. See CC licence page for more details.


The location of the earthquake in Katla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

More earthquakes like this should be expected in Katla volcano. But it is impossible to know if there is going to be an eruption in Katla volcano any time soon. But so far everything is quiet in Katla volcano. Besides occasional earthquake swarm that is taking place in Katla volcano.

Icelandic news about this earthquake activity

Jarðskjálfti í Kötlu – 3,2 að stærð (Rúv.is)
3,2 stiga skjálfti í Kötlu (mbl.is)
Snarpur skjálfti í Kötlu (Vísir.is)

Blog post updated at 19:34 UTC on 03.10.2012
Blog post updated at 05:45 UTC on 04.10.2012

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Earthquake activity east of Grímsey Island (TFZ). Possible fake earthquakes in Eyjafjallajökull volcano

At 03:03 UTC an earthquake with the early and unconfirmed magnitude of ML3.3 took place east of Grímsey Island. This earthquake did take place on TFZ. It is possible, but this earthquake might be the start of an earthquake swarm in this area. But that is not uncommon pattern for earthquakes in this area. But however it also happens that earthquakes like this one takes place. But then nothing more happens.


Earthquake activity in TFZ. The early magnitude ML3.3 earthquake is marked with a green star. Copyright of this image belongs to Icelandic Meteorological Office.

Eyjafjallajökull volcano

There has also been some earthquake activity in Eyjafjallajökull volcano during the night. This activity is possibly false due to weather or faulty SIL seismometer. The earthquake that have been detected so far have extremely low quality. But the increases the chance of them being false, rather then real events. It is not going to get known if this activity is real or not until it is reviewed by seismologist at Icelandic Meteorological Office.


The possible earthquake activity in Eyjafjallajökull volcano. This activity might be due to faulty hardware or weather, rather then real activity in Eyjafjallajökull volcano.Copyright of this image belongs to Icelandic Meteorological Office.

Eyjafjallajökull volcano has been quiet since it’s eruption in the year 2010. I do not expect that to change any time soon. Since it seem that Eyjafjallajökull volcano eruption cycle is around 150 to 500 year (theoretical maximum in my opinion). So I am not expecting anything to happen in Eyjafjallajökull volcano any time soon. If this earthquake activity is confirmed it is interesting. What might come out it is impossible to know for sure.

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Minor earthquake swarm in Katla volcano

Tonight around 22:30 UTC there was an minor earthquake swarm in Katla volcano. This earthquake swarm did last in about 20 minutes. After that the earthquake activity did drop back to normal background levels. This earthquake swarm is most likely part of normal autumn earthquake activity in Katla volcano. More earthquake swarms like this should be expected in Katla volcano during next few weeks.


Earthquake activity in Katla volcano this evening (28.09.2012). Copyright of this image belongs to Icelandic Meteorological Office.

What happens next is impossible to know. But I am not expecting anything special to happen in Katla volcano following this earthquake swarm. This earthquake swarm did appear clearly on my geophone at Skeiðflöt and Heklubyggð. The geophones can be viewed here.

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Minor earthquake swarm in Katla volcano

Normal autumn activity appears to be starting in Katla volcano. This earthquake activity is not something to be alarmed about. But worth keeping an eye on anyway.


The earthquake activity in Katla volcano during the past 48 hour period. Copyright of this image belongs to Icelandic Meteorological Office.

This is just normal autumn activity. As such it is not dangerous and does not mean anything. More earthquakes might happen in next few days to weeks.

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Earthquake activity drops in TFZ

During the past few hours earthquake activity in TFZ has dropped. This is not unusual. As earthquake activity in this area happens in swarms. Last earthquake swarm in this area where in the years 1996 and 2004. Those earthquake swarm lasted for several days and made several earthquakes with the magnitude 4. It is impossible to know how long activity is going last in this area. But since it has been ongoing for better part of current week (week 38). It might well be this activity is already over. But only time is going to tell what happens next. In current earthquake swarm. More then 500 earthquakes have been recorded so far.


The area of activity in TFZ. Stars mark earthquakes that are larger then magnitude 4 in size. But red dots show other earthquakes. The arrows show the fault movements in this area. It is from this news here on IMO web page. Copyright of this image belongs to Icelandic Meteorological Office.


The earthquake swarm as it looks during the past 48 hours. Copyright of this image belongs to Icelandic Meteorological Office.


The earthquakes on IMO tracker. It shows the magnitude of most of the earthquakes that have taken place during past 48 hours. Copyright of this image belongs to Icelandic Meteorological Office.

As sad before. It is impossible to know what happens next in this earthquake swarm. But it might well be that it is over by now. Only time is going to tell us what happens next in this. Chance of an larger earthquake taking place in this area remains high.

Almannavarnir announcement (Icelandic Civil Protection System)

Jarðskjálftahrina úti fyrir Norðurlandi (Almannavarnir.is, Icelandic)

Icelandic news about this earthquake swarm

Jarðskjálftar í Eyjafjarðarál (Icelandic, vedur.is)
Talsverð jarðskjálftavirkni á Norðurlandi (Icelandic, Vísir.is)
Fjórir skjálftar yfir 4 að stærð (Icelandic, mbl.is)
Íbúar geri ráðstafanir til að draga úr tjóni (Icelandic, mbl.is)

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TFZ earthquake swarm update at 20:50 UTC

This is a short update for the earthquake swarm in TFZ at 20:50 UTC.

At 19:42 UTC on 20.09.2012 an earthquake with the magnitude of ML4.2 took place on TFZ. This earthquake swarm was most likely felt in Siglufjöður town, Dalvík town and possibly more places around the epicenter of this earthquake. This earthquake did also appear clearly on my geophone network in Iceland. Swarm of smaller earthquakes did follow this larger earthquake as before.


The epicenter of the latest magnitude ML4.2 earthquake in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.


The progress of the earthquake swarm during the past 48 hour period. This earthquake swarm happens in swarm, with drop in activity between them. Copyright of this image belongs to Icelandic Meteorological Office.


The earthquake swarm as it did appear on my Hvammstangi geophone station. This image is released under Creative Commons licence. Please see CC licence page for more details.


The earthquake swarm as it did appear on my Heklubyggð geophone station. This image is released under Creative Commons licence. Please see CC licence page for more details.

It is impossible to predict the progress and development of this earthquake swarm. But I expect this earthquake swarm to continue for the next few hours to days. It might last longer then few days. But only time is going to tell us what is going to happen next in this earthquake swarm. I am going to post new update on this earthquake swarm once I have had the time to check some of this data. But that might take few hours until I can do so. At the longest, not until tomorrow. Depending on IMO work on this earthquake swarm data. I am going to post new updates on this earthquake swarm soon as possible if anything major happens.