Category: Earthquakes

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Ongoing earthquake activity in Katla volcano (Week 50)

Yesterday and today there has been some earthquake activity in Katla volcano. While this earthquake activity is less then what have been taking place during the past few months this activity is bit higher then it used to be during the winter times. The largest earthquakes so far have had the magnitude around ML2.0 (from what I can tell). Currently this earthquake activity is limited to three areas inside Katla volcano caldera according to report from Iceland Meteorological Office.


Earthquakes in Katla volcano during the past 48 hours. The ares with most earthquake activity can clearly be seen inside Katla volcano caldera. Copyright of this picture belongs to Iceland Meteorological Office.

This earthquake activity is more then compared to the winters few years back. Here is an comparison from the years 2009 and 2010 in Week 50 (current Week).


Earthquake activity in Katla volcano during Week 50 in the year 2009. Copyright of this picture belongs to Iceland Meteorological Office.


Earthquake activity in Katla volcano during Week 50 in the year 2010. Copyright of this picture belongs to Iceland Meteorological Office.

As can be seen with this comparison, the earthquake activity now in Katla volcano is considerable higher then in what is called an normal year in terms of activity in Katla volcano. What this means is unclear. But this suggests an eruption is not far away in Katla volcano. But when and how big is impossible to know at current time. Many of the earthquake swarms in Katla volcano are due to dike intrusions taking place in the Katla volcano caldera. But not all of them get to the surface to start an eruption. However such activity can and has increased hydro-thermal activity inside Katla volcano caldera. As has been evident during the past few months in Katla volcano caldera.

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Earthquake swarm in Bárðarbunga volcano

During the night there was an small earthquake swarm in Bárðarbunga volcano. The largest earthquake in this earthquake swarm was ML3.04 in magnitude. It had the depth of 8.5 km. This might have been a n dike intrusion. But it is hard to know that for sure at the moment. This earthquake swarm only lasted for an about 2 to 3 hours before it stopped.


The location of the earthquake swarm in Bárðarbunga volcano. Copyright of this picture belongs to Iceland Meteorological Office.


The earthquake swarm also did appear clearly on the tremor plots on the SIL stations that are close to Bárðarbunga volcano. The second set of spikes there are from Hamarinn volcano. Copyright of this picture belongs to Iceland Meteorological Office.


This earthquake swarm was also seen on Grímsfjall volcano SIL station. The rise in harmonic tremor is due to a storm that is passing over Iceland at the moment (going to go over Iceland today). Copyright of this picture belongs to Iceland Meteorological Office.

Hamarinn volcano

Following the earthquake swarm in Bárðarbunga volcano an earthquake swarm did start in Hamarinn volcano. This earthquake swarm is so far small and the largest earthquake so far is an ML1.9 in magnitude. But Hamarinn volcano had an minor eruption in July 2011. That minor eruption created an glacier flood that was larger then the flood that did come from Mýrdalsjökull glacier the week earlier. Activity after that has however been little and few earthquakes have taken place. It is impossible to know if there is going to be any more eruptions in Hamarinn volcano. But it cannot be ruled out given current activity in it.

Year in review on Rúv News

Rúv News has put up an page with major events in Iceland during the year 2011.

Grímsfjall volcano eruption in May 2011 can be viewed here.
The glacier flood from Mýrdalsjökull glacier due to the small eruption in Katla volcano can be found here. Sadly there is no mention of glacier flood from Hamarinn volcano yet.

This video should be available outside Iceland. If it is not. Please let me know I can send an complain email to Rúv News about it.

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Harmonic tremor continues to drop in El Hierro volcano

It seems that currently the eruption in El Hierro volcano is coming to an end. I do not know if this is an permanent end to the current eruption or just an short break in it. The reports that I have seen so far suggest that the main crater out of the coast of La Restinga has stopped erupting. The current harmonic tremor however suggests that an eruption is still taking place somewhere. But I have no idea where that might be at current time, and so far no clues where that might be. But the lack of earthquakes north of El Hierro Island suggests that an eruption might be taking place there. But that is just speculation.


The harmonic tremor in El Hierro volcano at 20:36 UTC. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

Other then this. There is not that much to report from the eruption in El Hierro volcano, or what is left of it at current time. If there are any major changes. I am going to report them soon as I can. But at current time. It does not look like there is isn’t a lot needed to be reported on the eruption in El Hierro volcano.

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More man made earthquakes in Hengill volcano

Since 04:49 UTC this morning (17 December, 2011) there has been an earthquake swarm in Hengill volcano. This earthquake swarm is due to hydro-thermal power production that is currently taking place in this area. But the Orkuveita Reykjavíkur (OR) is obligated to pump down cold water into the bedrock at depth that is greater then 800 meters. This water is used hot water that they pump up from the ground to warm houses and make electricity.


The earthquake swarm at 12:45 UTC on 17 December, 2011. Copyright of this picture belongs to Iceland Met Office.


The evolution of the earthquake swarm since it did start. Copyright of this picture belongs to Iceland Met Office.


The earthquake swarm as it did appear on my geophone at Heklubyggð. But the geophone at Eyrarbakki is scheduled to be up and running in next week. This picture is released under Creative Commons licence. See top bar for more information under CC Licence.

The earthquake swarm in Hengill volcano is currently ongoing. So far the largest earthquakes have had the size ML2.1 according to the automatic SIL system. Due the high number of earthquakes, the earthquakes have been wrongly placed on the map of Iceland that Iceland Met Office has. This are not real earthquakes in most cases, just wrongly located earthquakes that are taking place in Hengill volcano. The earthquake swarm is currently ongoing. If there are any major changes to this earthquake swarm. I am going to update this blog post with information about it.

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Update on the eruption in El Hierro volcano (13 December, 2011)

Here is a long overdue update on the eruption in El Hierro volcano. But the eruption in El Hierro volcano is now in its third month.

Overall there has not been a lot of change in the eruption that is taking place in El Hierro volcano. But from what I can gather the eruption is taking place in just one vent at the moment. But that is common with this type of eruption. As they start with an fissure, but they end up just one vent erupting and building an cinder cone. Currently the eruption is taking place underwater. But that does not stop it from building an cinder cone. If the eruption continues long enough it is going to form an new island in this location. If that happens, the eruption is going to go from ash making eruption and down to lava eruption. Islands that form in this type of eruptions stand an better chance of lasting more then few months in the ocean. As the eroding powers of the ocean can wipe out a new Island in matter of months if it is just made out of volcanic tuff material.


Current harmonic tremor in El Hierro volcano eruption. The spikes are believed to be explosions taking place in the eruption area. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


Steam event taking place in the eruption of El Hierro volcano. This picture is from 4 December, 2011. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

There is also an other event that has mostly gone unnoticed by people. But that is the fact that earthquakes have stopped in north part of El Hierro volcano, current rate of earthquakes is close to zero during 24 hour period. This strongly suggests that an eruption has started in north part of El Hierro volcano. I have no idea where it, as there are no signals at the surface of the ocean that give clues to where this eruption might be taking place. But an similar drop in earthquakes took place just after the eruption in south El Hierro volcano started. The depth in north part of El Hierro Island increases sharply and any eruption that is currently taking place on more depth then 1000 meters is going to be hard to impossible to detect properly.

I am going to continue to monitor the eruption in El Hierro volcano. If there are any major changes. I am going to report it soon as I can do so.

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Earthquake activity continues in Katla volcano

Even if it is December and Mýrdalsjökull glacier has added around 6 meters of snow on top of it self. It seems that the earthquake activity in Katla volcano is rather strong, even if it winter already in Iceland.


Earthquake activity in Katla volcano past 48 hours. Some of this earthquakes might be frost-quakes due the freezing weather in Iceland for the past few days. Copyright of this picture belongs to Iceland Met Office.

The earthquake activity in Katla volcano is resistant in the Katla volcano caldera and has been that for several weeks already. I cannot interpreted this earthquake activity other then Katla volcano is preparing for an eruption. But when I am not sure at this moment. There is an pattern of earthquakes in Katla volcano caldera, this pattern has been in place since Week 27, but that is the week when the minor eruption took place in Katla volcano caldera last summer (summer 2011).

It is clear that this earthquake activity in Katla volcano is going to continue. I am assuming that this earthquake activity is going to continue until a eruption takes place in Katla volcano. But there is also the chance of the year 1999 event. When a small eruption took also place and earthquake activity remained high for several weeks after that. But after some time the earthquake activity started to drop. For the moment I find that to be unlikely outcome given how long the earthquake activity has remained high in Katla volcano after the minor eruption this summer.

Donations: I am going to try and setup the geophones in Eyrarbakki village and the geophone close to Katla volcano in December. But that trip is going to cost me some money (I pay for the car benzine), but the cost might go as high €157, 1169 DKK, $210, 25.000 ISK (current exchange rates) just for gas (on an car) for that trip. So if anyone can help with this cost it would be welcomed. Thanks for the support! 🙂

Update 1: I am most likely going with the bus. But that also costs some money, around 3900 ISK, 182 DKK, 24€. $32, 20GBP (Current exchange rates).

Blog post updated at 13:12 UTC on 12 December, 2011.

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Earthquake activity in Katla volcano

Even if there is December and Katla volcano is supposed to have less earthquake activity during this time of year. It seems to be that currently that is not the case. But the earthquake activity is less then it was this summer after the minor eruption in July 2011. No major earthquake swarm has been taking place in Katla volcano for the past few weeks. But there is a lot of earthquakes taking place, without it being a earthquake swarm at one single location inside Katla volcano.


Current earthquake activity in Katla volcano. Copyright of this image belongs to Iceland Met Office.

Many people might ask if this earthquake activity is something to worry about. The answer is no. Katla volcano is unlikely to start an eruption in December. But if this pattern of earthquake activity it is clear that Katla volcano is going to erupt sooner rather then later. But the question after the mini-eruption last summer (July 2011), if there are going to be around 10 years until next eruption takes place in Katla volcano. For the moment nobody knows for sure.

Other: I want to remind people about the forum. It can be used to ask questions, chat, share pictures and so on.

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Harmonic tremor in El Hierro volcano drops

There was a change in the eruption in El Hierro volcano last night. The harmonic tremor started to drop of slowly. This drop in harmonic tremor comes several days after a drop in earthquake activity happened. But it might be possible that this drop in earthquake activity in north El Hierro volcano might be because a erupting vent did open up in north El Hierro volcano. But at such depth that the eruption was not noticed on the surface on the ocean. At least that might be the reason. But without any data, this is just a speculation. But at any rate, the earthquake activity in north part of El Hierro volcano has dropped down to almost zero in few days time.


The harmonic tremor yesterday (5 December, 2011). The drop in harmonic tremor can clearly be seen here. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor today at 08:15 UTC. The harmonic tremor continues to drop during the past few hours. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

The harmonic tremor drop is something that has happened before in El Hierro volcano. Just before a new fissure did open up in El Hierro volcano eruption. I am unsure if that is the case now. But it should become clear in about two to three days. But it is also a possibility that this eruption is coming to a end. But it has been erupting now for close to three months now. So this eruption might just ending. But we might have to wait a bit until that is confirmed. But at the moment the harmonic tremor is dropping and that means the eruption is smaller for the moment.

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Growing earthquake swarm in Krísuvík volcano

There seems to be a growing earthquake swarm in Krísuvík volcano on the Reykjanes peninsula. The strongest earthquake so far is a ML2.2 according to the automatic size estimate. Some ghost earthquakes appear to be outside a town called Akranes and Reykjavík to the north. But that are earthquakes that are in fact nothing but errors. This earthquake swarm is tectonic in nature, not volcanic. So there is not going to be a eruption in Krísuvík volcano from what I can tell at current moment.


The earthquake swarm in Krísuvík volcano. Copyright of this picture belongs to Iceland Met Office.

It is hard to know how this earthquake swarm is going to develop. But this earthquake swarm looks growing. For that it is going to peak in activity sometimes in the next few hours. But when exactly is hard to know for sure. I am going to update this blog post if something major happens. The strongest earthquakes appears on my geophone and can be viewed here.

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Earthquake swarm 14 km to the east of Akureyri town

At 19:22 UTC a small earthquake swarm started 14 km east of Akureyri town. The earthquake swarm started with a earthquake with the size of ML3.11 at the depth of 9 km. The area of activity is unusual, but there are none known fault lines in this area that I am aware of. This area is also a bit off TFZ fault zone. This area normally does not have any earthquakes. I am not sure yet if this are intra-plate earthquakes or not, as this area is close to the NVZ (North Volcanic Zone).

This earthquake was felt in Akureyri town by the local people. How well I do not know.


The area where the earthquake swarm is taking place. Copyright of this picture belongs to Iceland Met Office.

I did record the strongest earthquake on enough geophone to be able to make a plot map from my own software from software called WinQuake that I use to plot earthquakes time, location and depth information with data from Iceland Meteorological Office.


Here is the earthquake location according to my geophones with location data from IMO. This picture is released under Creative Commons licence. See top bar for more information.

Here are the wave form data that where recorded on my geophones (they can be viewed online here). The Sauðárkrókur geophone is a testing geophone that I am currently running. But it is going to be turned off now in December.


The earthquake as it was recorded on the Heklubyggð geophone. This picture is released under Creative Commons licence. See top bar for more information.


The earthquake on Hvammstangi geophone. This picture is released under Creative Commons licence. See top bar for more information.


The test geophone at Sauðárkrókur village. This geophone is noisy. This picture is released under Creative Commons licence. See top bar for more information.


The strongest aftershock that I did record on my Hvammstangi geophone. The wave form data on Sauðárkrókur geophone where not good for some reason. So I do not display them here. This picture is released under Creative Commons licence. See top bar for more information.

The wave form outside the earthquake are ocean waves. They are strong now and show clearly on my geophone. So they appear even more clearly on the SIL network as higher tremor levels. But that is nothing that looks like a volcanic harmonic tremor.

As for the earthquake swarm. It is hard to know what it means. But more aftershocks in this area for the next few days are not impossible. As has been seen before in areas that suddenly start to make earthquakes after a long break.

Icelandic News reports of this event. Please use Google Translate with care. It does not yet understand.

Jarðskjálfti við Akureyri (mbl.is)
Jarðskjálftar við Akureyri (Rúv.is)
Þrír jarðskjálftar nærri Akureyri (Vísir.is)

Blog post updated at 06:02 UTC on 3 December, 2011. Fixing errors in the text.