Category: Earthquakes

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A ML3.4 earthquake 25 east of Grímsey Island (automatic size)

When things gets busy in Iceland, they mean it. At least that is the case now. This also the reason why I do not trust the quiet times in Iceland.

A earthquake with the size of ML3.4 took place 25 km east of Grímsey Island in the TFZ at 21:46 UTC. But that is an non-volcanic zone that bridges the eastern volcanic zone with the North-Atlantic rift zone. This earthquake had an earthquake with the size of ML2.9 taking place before the larger one. That was an pre-earthquake most likely. But it seems that an earthquake swarm is also starting in TFZ as it has done close to Krísuvík volcano on the Reykjanes Ridge. I do not know if this earthquake was felt or not.

I am going to update this blog post if I need to.

Update 1: The location of this earthquake. So far there have not been any aftershocks following the ML3.4 earthquake. Its depth was at 11.5 km. This earthquake does not appear clearly on my geophones due to the distance involved (over 200 km).


The location of the ML3.4 earthquake on TFZ. Copyright of this picture belongs to Iceland Met Office.

Blog post updated at 22:22 UTC.

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A ML3.6 earthquake in Krísuvík volcano (automatic size)

At 21:12 UTC on 3. January 2012 an earthquake with the automatic size of ML3.6 did happen in Krísuvík volcano. I do not yet know if this earthquake was felt in the nearby area. But I assuming that it has done so.

This earthquake did appear clearly on my geophones. Both in north and south Iceland. They can be viewed here. I am going to update this blog post as I know more. But this seems to be an start of earthquake swarm in Krísuvík volcano.

Update 1: It has been confirmed that this earthquake was felt in Reykjavík and nearby area. The automatic depth of this earthquake was 14.2 km according to Iceland Met Office.

Update 2: Earthquake swarm has started in Krísuvík volcano. The largest earthquake in this earthquake swarm after the main earthquake is ML1.1 in size. Larger earthquakes however might happen at any time in this earthquake swarm. But that is at least the experience so far.

Update 3: Here are the traces of the earthquake. Sorry. But for the moment there are no high resolution pictures available as my main earthquake computer is offline until I move back to Denmark. See this blog post here for more details on that.


The location of the ML3.6 to ML3.7 earthquake in Krísuvík volcano. Copyright of this picture belongs to Iceland Met Office.


The ML3.6 earthquake as it did appear on Eyrarbakki geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.


The ML3.6 earthquake as it did appear on the Heklubyggð geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.


The ML3.6 earthquake as it did appear on the Hvammstangi geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.

Blog post updated at 21:38 UTC.
Blog post updated at 21:45 UTC.
Blog post updated at 22:15 UTC.

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Hekla volcano is quiet

I have been seeing some rumors about Hekla volcano might be about to erupt. This is wrong. For the moment Hekla volcano is quiet as it has been since the last eruption in the year 2000. For few years Hekla volcano did erupt for about every 10 years. That might have change already. Nobody is sure on that now. But one thing is clear Hekla volcano is going to erupt one day. But when is always the question.

People have been speculating on the earthquakes west of Hekla volcano. This earthquakes do not belong to Hekla volcano. They are part of activity in the SISZ (South Icelandic Seismic Zone). Earthquakes in this area tectonic in nature, not volcanic. So in worst case, this earthquakes might be sign of new major earthquake preparing to take place some day in the future.

For the moment however. Everything is quiet in Hekla volcano.

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Hydrothermal activity in El Hierro volcano

For the moment the eruption in El Hierro volcano has ended. The current harmonic tremor that is being detected might well be from hydrothermal activity that is currently in the area that erupted. But even if the eruption has ended, the area that erupted is going to be warm for many weeks to come. This is going to create hot springs below the sea level, among other ocean phenomena connected to this type of hydrothermal activity.


Harmonic tremor levels remain close to background levels at El Hierro volcano. Taken today at 16:05 UTC. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

As for future activity in El Hierro volcano. It is important to remember that eruption activity might start again on a new fissure. But that would be pre-seeded by earthquake activity. After the eruption activity stopped there has been some earthquake activity. But it is not at that level I would expect before a new eruption where about to start in El Hierro volcano. For the moment however things remain quiet in El Hierro volcano. A relieve to the local people in the area I would think.

Other

I want to remind people of the volcano and earthquake forum. It allows for more discussions on volcanoes, earthquakes and other stuff that might not belong to this blog.

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Overview of activity in Iceland, Spain and Canary Islands

This is a overview of activity in Iceland, Spain and Canary Islands. This is just an short overview. So not all events are included. But it has been quiet during the Christmas holidays.

Iceland

During the 24 to 26 of December there was not a lot of earthquake activity in Iceland. Three small earthquake swarm took place in Katla volcano. In Hengill volcano there was one small earthquake swarm in a location where earthquakes swarms have been taking place for past few weeks. In Katla volcano there was a earthquake swarms inside the caldera. This earthquake swarm are an reminding sign of the activity that is currently taking place in Katla volcano. But this activity took place in north-west part of the caldera. Since Sunday the activity in Katla volcano has again dropped for the time being. But that might change at any time. The largest earthquake that happened was an ML2.3 earthquake. It appeared clearly on my geophone at Heklubyggð.

Stormy weather in Iceland has made it difficult to monitor earthquakes during the past days. This is unlikely to change in next few days. As the path of the winter storms appears to be directly over Iceland at the moment.

Other then this. There was general quiet scene in Iceland during this weekend in Iceland.

Spain

During the weekend Spain had many minor earthquakes. With the largest one going up to ML3.5 in size, based on automatic size estimate. I do not know if anyone of this earthquakes where felt by humans. This earthquake activity is normal for Spain.

Canary Islands

The eruption in El Hierro volcano continued as it has been doing for the past three months. No earthquake appeared on the IGN automatic earthquake list. Harmonic tremor remained the same during the weekend. But yesterday and today there have been reports of new fissures opening. But this does not appears to have changed the harmonic tremor levels on the seismographs on El Hierro Island. This suggests that the currently the eruption remains the same. But I do not know what main eruption vents are open at the moment. They might be at great ocean depth and there eruption signs might not appear on the surface of the ocean.

Other then this it has been quiet in Canary Islands.

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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.