Category: Earthquakes

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New earthquake magnitude information

According to news announcement (Icelandic) from Iceland Meteorological Office the largest earthquake in the ongoing earthquake swarm at TFZ had the magnitude of Mb5.6. Currently the earthquake swarm in TFZ is ongoing. This is the largest earthquake in TFZ since the year 1976, when a magnitude 6.2 earthquake did take place not far from Kópasker village.


The star marks the location of the magnitude 5.6 earthquake. The red dots show the current earthquake swarm, the white dots show the earthquake swarm that took place in early September. Copyright of this image belongs to Icelandic Meteorological Office.

The earthquake swarm in this area of TFZ is currently ongoing and does not show any signs for now that it is stopping. But earthquakes with magnitude 3.0 and stronger are still taking place and might still take place in the next few hours tod days. Any strong earthquake is going to appear clearly on my geophone network in Iceland. If anything major happens. I am going to post new blog post about it soon as possible. I update my twitter and Google+ when needed.

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TFZ earthquake swarm update at 11:54 UTC

This is short TFZ earthquake swarm update at 11:36 UTC. The strongest earthquake so far was a magnitude Mb5.2. It has been followed by many earthquakes that are 3.0 to 4.8 in magnitude. Number of earthquakes that are below that magnitude is around 300 to 350. But this number is updating constantly so it is going to be outdated once this blog post is up.


The earthquake area today at 11:25 UTC. The green stars show earthquakes that are above ML3.0 in magnitude. Copyright of this image belongs to Icelandic Meteorological Office.


The tracker showing how dense this earthquake swarm was at times. Copyright of this image belongs to Icelandic Meteorological Office.


The earthquake swarm on Hvammstangi geophone station. This image is released under Creative Commons licence. See licence page for more details.


The earthquake swarm on Heklubyggð geophone station. This image is released under Creative Commons licence. See licence page for more details.


The tremor plot at Hraun á Skaga showing this earthquake swarm clearly. Copyright of this image belongs to Icelandic Meteorological Office.


The tremor plot at Siglufjöður. This SIL station is closest to the earthquake swarm. Copyright of this image belongs to Icelandic Meteorological Office.


The tremor plot in Grímsey Island. This tremor plot is showing the earthquake swarm clearly. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake swarm is not over at current time. But earthquake activity has dropped something for the moment.That might change at any time. Since this earthquake swarm does not show any signs of being over at the moment. There is no risk of volcano activity in this area following this earthquake swarm. Since there are no volcanoes in this area of Iceland. This earthquakes are strike-fault earthquakes. I am going to post more updates on this earthquake activity during the day, or when something major happens in this area.

This earthquake swarm has been felt in Siglufjöður town. The largest earthquake was felt over most of north Iceland. Some minor damage has been reported following that earthquake.

Blog post updated at 11:54 UTC on 21.10.2012. Added images that I forgot to add the first time around.

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Heavy earthquake activity in TFZ

At the moment there is heavy earthquake activity taking place in TFZ. With earthquakes taking place every second. Strong earthquakes taking place every 2 to 10 minutes. One earthquake has at least reached the magnitude 5.0 and more earthquake with that magnitude is currently taking place on TFZ.

This earthquake activity can be monitored live (5. min, delay) on my geophone network web page here. I am going to post more information when I have more details.

Update 1: According to USGS the largest earthquake had the magnitude of M4.8. I do not know if this is reviewed data or not. USGS data can be viewed here.

Blog post updated at 01:02 UTC on 21.10.2012.

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Earthquake activity update on 20.10.2012 at 14:51 UTC

Today (20.10.2012) has been busy in terms of earthquake activity in Iceland. So I am expecting to write a second update later today on this activity.

Hekla volcano

At 05:28 UTC there was an earthquake in Hekla volcano. This earthquake had the magnitude of ML1.1 with the depth of 0.6 km. No other earthquakes have followed this single earthquake. What this means is impossible to know at this time. But so far everything remains quiet in Hekla volcano.


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

Kverkfjöll volcano

Earthquake activity continues in Kverkfjöll volcano. This earthquake activity is the result of dike intrusion into Kverkfjöll volcano. So far this earthquake activity is taking place in short burst of earthquake swarm.


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

Tjörnes Fracture Zone

At 02:07 UTC earthquake activity did start in TFZ. Just off the coast of Iceland. This earthquake activity is taking place in area that last had earthquake swarm in September. I did cover that earthquake activity in details on this blog. So far the largest earthquakes in this area of TFZ have had the magnitude of ML2.9. This is purely tectonic earthquake activity.

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

It is difficult to know what happens next in TFZ earthquake activity. But it likely going to continue for the next few hours to days like earlier. It is best to keep an eye on this earthquake activity. This earthquake activity also sometimes stops for few hours before it continues again. Most of this earthquake activity can be seen on my geophone network web page.

If anything major happens in this earthquake activity. I am going to post new blog post with updated information on that activity.

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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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Glacier-quakes and ice-quakes taking place in Iceland

In some parts of Iceland, mostly in the high areas of Iceland the ground is freezing over this time of the year. This is creating a lot of glacier-quakes and ice-quakes in Iceland. On Icelandic Meteorological Office earthquake maps this appears as earthquakes with extremely poor quality. Many of the earthquakes in and around Mýrdalsjökull glacier and Eyjafjallajökull volcano are glacier-quakes and ice-quakes.

So while it might appear as a lot of earthquake activity is taking place. That might not be true earthquakes. In this case, it is best to wait for reviewed data on this activity. To see what is real earthquake activity and what is not real earthquake activity.

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New earthquake swarm east of Grímsey Island

This night there where two minor earthquakes on TFZ (according to the Richter scale). According to automatic results from Iceland Meteorological Office. The first earthquake had the magnitude of ML3.7 and the second earthquake had the magnitude of ML3.5. Many smaller earthquakes took place between this earthquakes. Most of them with the magnitude of 1.0 to 2.5. Earthquake activity is currently ongoing in this area at the moment. Earthquake activity started east of Grímsey Island around 00:04 UTC, 13.10.2012. The first earthquakes where smaller then 2.0 in magnitude.


The earthquake swarm on TFZ during the night. Copyright of this image belongs to Icelandic Meteorological Office.

This area of TFZ is well known for earthquake activity. During past few weeks it had several earthquake swarms around this location. More earthquakes should be expected in this area in next few hours to days. I do not know if any of this earthquake activity has been felt in Grímsey Island.

Blog post updated at 08:05 UTC.

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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)