Category: TFZ

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Ongoing earthquake activity north-east of Flatey in Skjálfanda fjord (north-east Iceland)

Earthquake activity that started in March 2017 in TFZ (Tjörnes Fracture Zone) is ongoing. I don’t know yet how many earthquakes have happened so far, but at last check Icelandic Met Office reported that the mark was at 800 and that was more then a month ago. The fluid that is pressuring up at this location between fault lines is most likely a magma in my view. If that results in a eruption is harder to say, at the moment the magma seems to be stuck at 10 km depth (in or around that depth).


The current earthquake at Flatey in Skjálfanda fjord. The location is where the yellow and orange dots mix (slightly east of Eyjafjörður fjord). Copyright of this image belongs to Icelandic Met Office.

The earthquake activity at this location continues with little signs of stopping. What is also interesting is the fact the magma doesn’t seems to be making any progress up the crust at the moment. With fault line already in place the path to the surface is almost direct in this area if nothing is preventing the magma from moving upwards (impossible to know). At the moment this earthquake activity is limited to minor earthquakes and this magma seems to be lacking pressure to reach the surface at the moment. At this location there are no known volcanoes.

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Fluid reason for earthquake swarm north-east of Flatey in Skjálfanda, Tjörnes Fracture Zone

In March-2017 an earthquake swarm started north-east of Flatey in Skjálfanda in Tjörnes Fracture Zone. This earthquake swarm is ongoing as is. Largest earthquake this this swarm only has the magnitude of 2,5. All other earthquakes have been smaller in magnitude, since March around 800 earthquakes have been recorded north-east of Flatey in Skjálfanda.


Flatey in Skjálfandi earthquake activity since March-2017. Copyright of this image belongs to Icelandic Met Office.

There are two faults at work here, the first one is in north direction and close to vertical. The other is in the direction of NW-SW (around 145 degrees east) and has an angle of 60 – 70 degrees. Depth is around 10,5 to 11,5 km. Since March, according to Icelandic Met Office report the earthquake activity has slightly migrated north. As the earthquake activity has moved north, they have moved upward to a slightly shallower depth.


The NW-SW fault plane in the earthquake swarm north-east of Flatley in Skjálfanda. Copyright of this image belongs to Icelandic Met Office.


The fault plane that is almost directly north and vertical. Copyright of this image belongs to Icelandic Met Office.

There are clues in this earthquake swarm that it is caused by some type of fluid migrating in the faults at this location. What type of fluid this might be is not possible to know. There are no known volcanoes at this location or any historical accounts of an eruption in this location. I don’t know if there are many options for what type of fluid this might be pressing it self up at this location, magma is one possibility but this might also just be water moving upwards in the crust at this location.


Number of earthquakes north-east of Flatey in Skjálfandi since Marc-2017 until June-2017. Copyright of this image belongs to Icelandic Met Office.

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Article updated at 00:47 UTC. Location error fixed. I confused fjords in the area together.
Article updated at 01:47 UTC. I forgot the image with number of earthquakes at north-east of Flatey in Skjálfandi.

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Earthquake swarm in Tjörnes Fracture Zone east of Grímsey island

Today (09-June-2017) there has been a earthquake swarm in Tjörnes Fracture Zone east of Grimsey island. This was fairly large earthquake swarm in number of earthquakes that happened. Largest magnitude that happened was 2,2 and second largest was 2,1. All other earthquakes where smaller and I think around 40 earthquakes happened in this earthquake swarm.


The earthquake swarm east of Grímsey island on TFZ. Copyright of this image belongs to Icelandic Met Office.

It seems that this earthquake swarm is over, at least for now. This area of Tjörnes Fracture Zone has been showing increasing earthquake activity over the last few weeks. It is difficult to know if that keeps up as it has been doing.

The earthquake swarm off Flatey island is now entering its fifth or six week. There are no signs of that earthquake activity quieting down for now at least.

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Earthquake activity in Tjörnes Fracture Zone (TFZ)

For the past month (or so) there has been a constant earthquake activity close to Flatey island on the Tjörnes Fracture Zone (TFZ). This earthquake swarm has not been strong, with majority of the earthquakes only having the magnitude of 0,0 – 2,5 and only one or two earthquakes with magnitude 2,8 – 3,0. While this earthquake swarm might not be a risk, it might suggest that something is about to give in this area.


The earthquake activity in TFZ as it is today. The activity close to Flatey island is clearly visible. Copyright of this image belongs to Icelandic Met Office.

Other areas of TFZ have also been having minor earthquake swarms. I don’t think they are connected to this activity near Flatey island. None of those earthquake swarm have been big in both number of earthquakes and magnitude. TFZ is Iceland most active earthquake area with hundreds of earthquakes taking place each year. What is unusual now is the earthquake activity close to Flatey island, but this is not the first time this type of earthquake swarm happens in TFZ. Normally this type of earthquake swarm slowly die out without anything major happening.

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Earthquake swarm under Grímsey island (Tjörnes Fracture Zone)

Yesterday (25.01.2016) there was an earthquake activity directly under Grímsey island (Wikipedia information). Earthquake swarms directly under Grímsey islands are uncommon, but they do happen from time to time. Current earthquake swarm is getting close to a mid-range scale (as I count them) in number of earthquakes, with around 36 earthquakes recorded so far. Some of this earthquake activity must have been felt in Grímsey island, even if it has not been reported anywhere (that I know of). This earthquakes are not large enough to create any damage, just a little rattle of glasses and dishes in cabins and such items.


The earthquake activity directly under Grímsey island. Copyright of this image belongs to Icelandic Met Office.

Largest earthquakes in this swarm had the magnitude of 2,8 and 2,7. Other earthquakes have been smaller in magnitude so far. I don’t think this earthquake swarm is over at the moment, even if the earthquake activity has dropped at the moment.

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Article updated at 02:23 UTC.

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Two minor earthquake swarms on TFZ

Over the past two days minor earthquake swarms have been taking place on the TFZ. Largest earthquake in this swarm had the magnitude of 3,0.


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

There is a change of more earthquake activity in this area in next few days to weeks. Since 2016 was considerably quiet in the TFZ.

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Minor earthquake activity on TFZ (Tjörnes Fracture Zone)

It is quiet in Iceland at the moment. Nothing much to report, so I’m reporting this minor earthquake activity in TFZ.

Few earthquakes have happened in TFZ for the last 48 hours, most earthquakes have been small and the largest ones have reached magnitude 2,5.


Minor earthquake activity in TFZ. Copyright of this image belongs to Icelandic Met Office.

This type of quiet period is common in Iceland. Since activity happens in bursts with long quiet spells between them. Since this website mostly reports current events, rather than anything historical I don’t have a lot to write about at the moment. I’m considering writing about other global activity while it’s quiet in Iceland.

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Earthquake activity close to Grenivík (TFZ/Dalvík Fault-line area)

At 09:41 UTC on 19-December-2016 a small earthquake swarm started on the Dalvík fault-line, that fault-line is part of TFZ (Tjörnes Fracture Zone area). The largest earthquake was felt over a wide area, including Akureyri and other nearby towns. Largest earthquake in this swarm had the magnitude of 3,5 and the second largest earthquake had the magnitude of 1,6. The largest earthquake depth was 12,3 km.


The green star show the active area. Copyright of this image belongs to Icelandic Met Office.

When this text is written it seem that the earthquake activity has dropped down, just one earthquake has happened since the activity stopped at 09:49 UTC. Current level of activity is low and that might remain like that.

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Minor earthquake swarm on TFZ

Today (14-November-2016) a minor earthquake swarm started on TFZ (Tjörnes Fracture Zone). Largest earthquake so far has the magnitude of 3,2, other earthquakes have been smaller in magnitude.

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

So far this earthquake swarm has not been big and it doesn’t look like its going to develop into a big earthquake swarm at the moment. In other parts of Iceland everything is quiet, with just one off or few earthquakes happening in each location.

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Overview of micro-earthquake activity in Iceland 28-September-2016

This is a short overview of the micro-earthquake activity in Iceland on 28-September-2016. Please note that some of this earthquake activity may have started some days ago and only got really busy on 28th September 2016.

Kolbeinsey Island / Ridge

Late on the 28-September-2016 an earthquake swarm took place in Kolbeinsey Island / Ridge. This is the largest earthquake swarm in this article. With the largest earthquakes having the magnitude above 3,0. Due to distance from the SIL network exact calculation of the magnitude and depth doesn’t appear to be possible. Last eruption taking place in Kolbeinsey Island / Ridge took place in the year 1755. No other eruptions have been documented since, but they might regardless have happened. The area is far from land and difficult to observe.

East of Grímsey Island (Tjörnes Fracture Zone)

Minor earthquake swarm has been taking place earth of Grímsey Island in a area that many suspect is a volcano (it is marked as such in the GVP database). The earthquake swarm in question does not appear to be a volcanic in origin. This appear to be a tectonic activity taking place, as the movement of TFZ is 20mm lateral movement/year (they fault slide each other 20mm/year) the rift movement is only 5mm/year (eastern part only). Image showing the movements can be found here (vedur.is).

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Earthquake activity in Kolbeinsey Island and Tjörnes Fracture Zone. Copyright of this image belongs to Icelandic Met Office.

South Seismic Zone (SISZ)

A small swarm of earthquakes has been taking place in SISZ this week. The largest earthquake in this swarm has only had the magnitude of 2,1. The activity is only minor and does not suggest a large earthquake is about to happen. This might be aftershocks of the earthquakes in 2000 or 2008.

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The earthquake activity in SISZ. It’s only minor and west of Selfoss (red dot). Copyright of this image belongs to Icelandic Met Office.

Reykjanes peninsula

Earthquake swarm started on 28-September-2016 on the Reykjanes peninsula. This earthquake swarm was not strong and the largest earthquake in this swarm only had the magnitude of 2,1 and all other earthquakes where smaller in magnitude. Total of 60 earthquake happened when the swarm was active.

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The earthquake swarm on the Reykjanes peninsula. It was not big in magnitude, but had a total of 60 earthquakes. Copyright of this image belongs to Icelandic Met Office.

Few earthquake have also been taking place around Iceland without any other activity. This type of one-off earthquake activity is common in Iceland. Why it happens is unclear.

Article updated at 02:03 UTC on 29-September-2016. Word corrections.