Category: Dyke intrusions

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Earthquake swarm in Katla volcano yesterday (07.June 2012)

Yesterday there was an earthquake swarm in Katla volcano. Over 50 earthquakes have been recorded so far. But this earthquake swarm stopped yesterday at 16:22 UTC. Most of the earthquakes where shallow, with depth less then 1 km. Largest earthquake had the magnitude of ML2.5. No harmonic tremor was detected following this earthquake swarm. But that is unlike what did happen last year, when a similar earthquake swarm took place in Katla volcano.


Earthquake activity in Katla volcano yesterday (07. June. 2012). The main areas appear clearly on this map. The small dot SE on the caldera rim is an area that became active after last years minor eruption. What is taking place there is still an mystery. Copyright of this picture belongs to Iceland Meteorological Office.

This activity appears to be similar to what happened around 9th July, 2011. But no harmonic tremors are taking place in Katla volcano following this earthquake swarm.


Earthquake activity in Katla volcano on 9. July 2011. This good to compare the earthquake activity yesterday (image above this one). Copyright of this picture belongs to Iceland Meteorological Office.


The ML2.98 magnitude earthquake that happened in Katla volcano yesterday (07. June. 2012). This is the earthquake as it was recorded on Skeiðflöt geophone station. This image is released under Creative Commons License. See License page for more details.


Same earthquake as above. But filtered at 1Hz and this is how the earthquake appeared in Heklubyggð geophone station. This image is released under Creative Commons License. See License page for more details.

So far this is just an earthquake swarm. As there are no harmonic tremor signal taking place as the earthquake swarm is taking place. I do not know if there has been any glacier flood following this earthquake swarm. But if there was. It would mean that hydrothermal vents under Mýrdalsjökull glacier have been emptying out. It happens regularly in glacier such as Mýrdalsjökull glacier.

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Earthquakes in Katla volcano. Earthquake swarm continues close to Herðubreið. Other earthquake activity

This morning there was a short earthquake swarm in Katla volcano caldera. This earthquake looks like a minor dike intrusion did take place this morning. Current series of events did start on 28. April 2012. With a small earthquake event and a small glacier flood that did follow it. Along with harmonic tremors coming from the glacier flood and possibly Katla volcano caldera (hydro-thermal activity boiling or something of that nature). I do not yet know if there was any glacier flood following the event this morning. But so far there is nothing that suggests a small glacier flood did take place following the earthquake swarm this morning.

The earthquake swarm this morning took place on an location that did erupt on 8 and 9th of July 2011. So it is clear the area that erupted last year is picking up activity again. But there was an drop in activity from end of November 2011 until end of April 2012.


Earthquake activity in Katla volcano this morning. Copyright of this picture belongs to Icelandic Meteorological Office.

This earthquake activity did appear well on my geophone at Skeiðflöt farm.


Earthquake activity in Katla volcano caldera this morning on my Skeiðflöt geophone. There is a lot of noise on this geophone. But earthquake activity can still be seen on this. The earthquakes are marked by red (some noise is also marked by red). This picture is released under Creative Commons Licence. See CC Licence page for more details.

It is clear that Katla volcano seems to be warming up to an eruption. But it is impossible to know when such eruption might happen, or how big it is going to be.

Herðubreið

Earthquake activity continues south-west of Herðubreið. But almost all of the earthquakes have been less then ML2.0 in magnitude. Earthquake activity has been slowing down all day. At the moment, it appears this earthquake swarm is close to being over.


The earthquake activity close to Herðubreið mountain. Copyright of this picture belongs to Icelandic Meteorological Office.

This area is well known for for earthquake activity. So this is not something that is new in this area.

Reykjanes Ridge

According to EMSC and USGS there have been several earthquakes with the magnitude of Mb4.5 to Mb4.8 on the Reykjanes Ridge. Earthquake activity is common on the Reykjanes Ridge. But because of the location and depth (around 2km) it is impossible to know if there any volcano eruption taking place at this location. It might well be, or not.

Kolbeinsey Island

Over the past weeks there has been some earthquake activity close to or in Kolbeinsey Island. The largest earthquakes have had the magnitude around ML3.0, with some underestimates due to distance from the SIL network. At this moment it is impossible to know if this earthquake activity is related to possible eruption activity. But it believed that an eruption (or dike intrusion) took place on Kolbeinsey Ridge in the year 1999. It started off with a large earthquake swarm.

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Katla volcano warming up for an eruption. Small glacier flood continues

This is going to be a short blog post. As I am going to be short of table and a cheer for few more days.

It seems that Katla volcano is warming up for a eruption. As I did mention in last blog post. But there is more to this. As the glacier flood that started on the 28. April 2012 continues according to a email that I got from an geologist working at Iceland Meteorological Office. But that suggests two things. That there is currently an ongoing melting of glacier taking place in Katla volcano, or there is a slow drainage taking place from some area in Mýrdalsjökull glacier. But given increased conductivity following this it is clear that this water has been in contact with magma. But that can be seen with the increased conductivity in the water.

There have not been many earthquakes following this events. But from the earthquakes that have happened. It seems that most likely source for current events is close to or the same area that erupted in July 2011. But at the moment this is just speculation based on limited data. It has not been confirmed so far.


The harmonic tremor that started on 28. April 2012. This is Lágu Hvolar SIL station. Copyright of this picture belongs to Iceland Meteorological Office. Used with written permission.

This plot shows clearly how the harmonic tremor starts and continues at same level for several days. I do not know if the harmonic tremor is ongoing. But I find it likely, if the small glacier flood is currently going on (that was my last information, but things might have changed during the day). But it is hard for me to know that for sure. But based on latest data from the water monitoring system around Katla volcano, the spike in this glacier flood is most likely over for now. But it impossible to know what happens next in Katla volcano. All that can be done is to wait and see what happens next.

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Few earthquakes in Hamarinn volcano and Kverkfjöll volcano

After several weeks of quiet period, activity in the volcanoes that are close to or in Vatnajökull glacier. During the past few days there have been earthquakes in several volcanoes in Vatnajökull volcano. Today it is the Hamarinn volcano and Kverkfjöll volcano.

Hamarinn volcano (Loki-Fögrufjöll)

Hamarinn volcano had its first eruption in July 2011. This eruption was small and started without even a hit of earthquake activity. It created a glacier flood that topped at 2100 M3. It did not create any damge. But it filled a human made lake that is used for power production in this area. That eruption was short, it only lasted for about 24 hours, maybe even less. Today this area of Hamarinn volcano has been having minor earthquake swarm. But this does not mean it is going to erupt again. But it also shows that current activity in Hamarinn volcano is not over.


Earthquake activity in Hamarinn volcano today (08.04.2012). Copyright of this picture belongs to Iceland Meteorological Office.


The earthquakes seen on Skrokkalda SIL station. The earthquakes from Tungnafellsjökull volcano are also clear on this tremor plot from Iceland Meteorological Office. Copyright of this picture belongs to Iceland Meteorological Office.

Kverkfjöll volcano

Kverkfjöll volcano have been warning up to a eruption for some time now. When they might erupt is impossible to know at current time. But it is save to say that at present time, no eruption is going to take place any time soon. This however means that earthquakes are increasing in Kverkfjöll volcano. Most of the time there are just small earthquake swarms in Kverkfjöll volcano. No other changes have so far been noticed in Kverkfjöll volcano. But that is unlike what has been taking place in Askja volcano in the past few weeks.


Earthquake activity in Kverkfjöll volcano. This are just small earthquakes so far. Copyright of this picture belongs to Iceland Meteorological Office.


The tremor plot from the SIL station that is closest to Kverkfjöll volcano. It just barely shows the earthquakes that have been taking place in Kverkfjöll volcano. Copyright of this picture belongs to Iceland Meteorological Office.

After several weeks of quiet in Iceland it seems to be that the quiet period is over. But if it is going to going to result in any major activity is impossible to know at this point.


Volcanoes of Iceland. Copyright unknown, Google Inc. But the picture is from here (warning! Conspiracy web site.)

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Look at Tungnafellsjökull volcano earthquake swarm

Here is a quick look at the earthquake swarm in Tungnafellsjökull volcano this morning. This earthquake swarm is interesting, as it started with few earthquakes at the depth of around 10 km. This suggests that magma might be pushing up to the volcano at depth now. So far this is not any high volume in my option, at least not enough to start an eruption now. But if this progress continues, it is going to end with an eruption one day. But when and how big is impossible to know at current time. for the moment the earthquakes have stopped. But it is my opinion that this a dike intrusion, not tectonic earthquakes. This can be seen how the earthquakes line them self up from 12.6 km depth and up to 3.6 km depth in almost straight line based on there location.


The earthquake swarm in Tungnafellsjökull volcano. Copyright of this picture belongs to Iceland Meteorological Office.

The earthquake swarm is dense, but that suggests an magma dike intrusion from deep within the volcano. Similar earthquakes have been seen in other volcanoes, like Esjufjöll, Askja, Katla so few are mentioned. So I know this pattern when I see it.


The earthquake pattern as it did appear on Skrokkalda SIL station. The tremor chart shows that the earthquakes where high-frequency earthquakes for most part. Something like that was seen in Eyjafjallajökull volcano before it erupted (it had earthquakes like that many years before it erupted, not just few weeks before). Copyright of this picture belongs to Iceland Meteorological Office.

I did record the largest earthquake on my geophone at Hvammstangi and at Heklubyggð. Based on that trace, the earthquake was noisy. Given me even more clues that support my suggestion that the earthquake swarm was due to dike intrusion.

Similar dike intrusion events are now taking place in Kverkfjöll volcano. But I am going to write about that tomorrow. But earthquakes in Kverkfjöll volcano have been taking place for several years now, with short and long breaks between earthquake swarms.

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Interesting earthquake activity in Tungnafellsjökull volcano

This is not the most known volcano in Iceland, it also has not erupted in the last 10.000 years at least. Normally this volcano does not have any earthquakes and it remains really quiet. Last major earthquake activity was in the year 1996 in relation to the activity in Bárðarbunga volcano and in Grímsfjall volcano that year. This volcano is named Tungnafellsjökull. It is a small volcano compared to other volcanoes in the area. During the past few days there have been several interesting earthquakes in Tungnafellsjökull volcano. They are small, around ML1.6 the largest ones. But they do have the depth of 10 to 12 km. That is what makes this earthquake activity interesting. Since this suggest that magma might be pushing into the volcano. However at this point in time, there is nothing to suggest an eruption is even close to start there. But with all long dormant volcanoes, nobody never knows what can happen next in them.


The earthquake activity in Tungnafellsjökull volcano. The volcano is located NW of Vatnajökull glacier. Copyright of this picture belongs to Iceland Meteorological Office.

Following the later earthquake today. This activity started on Skrokkalda SIL station. But this might be due to activity in Hamarinn volcano (Loki-Fögrufjöll at GVP). Not Tungnafellsjökull volcano.


The odd tremor activity on Skrokkalda SIL station. I do not yet have any explanation for this activity. Note that Skrokkalda SIL station is on top of a volcano (not on GVP list, but geological maps made in Iceland), named Skrokkalda, it also has not erupted in historical times to my knowledge. Copyright of this picture belongs to Iceland Meteorological Office.

What happens next in Tungnafellsjökull volcano is impossible to know. But it is most likely going to do what it has been doing for the past 10.000 years. A lot of nothing.

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Overview of current events in Askja volcano

The current events in Askja volcano started in Week 9 of the year 2010. Before that, Askja volcano has been showing signs of change since the year 2007 at least. In the year 2010, Week 9 a earthquake swarm was recorded by Iceland Meteorological Office. Most of the earthquakes where at around 20 km depth, and it was followed by considerable amount of harmonic tremor activity. I did know about it at the time, but I did think it would be at least 10 to 20 years until Askja volcano would not erupt. But this might have been a event in an series of event that started long time ago, without me knowing about it before (I am still checking data, it takes some time).


The earthquake activity in Askja volcano in Week 9 of the year 2010. Copyright of this picture belongs to Iceland Meteorological Office.

The image above clearly shows where magma was flowing into Askja volcano around 20 km depth. But they are to the north-east of Askja lake. The depth of this earthquakes was from 20 to 23 km.


Map of earthquake activity in Askja volcano. The green dots are earthquakes with a shallow depth, that is depth from 2 to 8 km. Yellow earthquakes have the depth of 12 to 30 km. This data is from the year 2007 at least. Copyright of this picture belongs to its owner (Janet Key).


The depth of the earthquakes in Askja volcano. Copyright of this picture belongs to its owner (Janet Key).


Depth of the earthquakes. This view shows also where the earthquakes are taking place in Askja volcano and close to it. Copyright of this picture belongs to its owner (Janet Key).

All of this map and charts are from this blog post here.


This is a heat camera image of Askja lake. Copyright of this picture belongs to Iceland Coast Guard, the image is from here.

Last year (2011) there was an dike intrusion in north part of Askja volcano. This dike intrusion was clear by a earthquakes that took place. But it stopped and has not shown any activity again in this area. As sometimes happens with dike intrusions. But this activity is an good sign that magma is now flowing into Askja volcano again. But over period of at least 10 to 20 years, it seems that magma has been flowing out of Askja volcano system. Where it has been going I have no idea. But some hypothesis suggests that it might be flowing into Krafla volcano. But there is no good data to support this hypothesis in partial.


Activity in Askja volcano in the year 2011. This activity took place on 05.05.2011 at 16:25 UTC. Copyright of this picture belongs to Iceland Meteorological Office.

At the moment there is nothing that suggest eruption is imminent. But current progress in Askja volcano is something to keep an watch on. But it is also clear that current status in Askja volcano is changing fast. So while there is nothing to suggest a eruption at the moment, it might change without warning in Askja volcano.

Pictures of Askja lake.

Askja lake 12 June 2011.
Picture of Askja lake (32 months ago according to flickr.)

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Minor earthquake cluster in Katla volcano caldera

There seems to be forming of minor earthquake clusters in Katla volcano caldera. But this has been following growing number earthquakes in Katla volcano caldera during past few weeks. This is most likely an signal of increased activity in next few weeks to months. But the increase does not have to been slowly up. It can be sudden as did happen in July 2011 in Katla volcano caldera when earthquake activity did increase suddenly and there was an small eruption without an warning.


Current earthquake activity in Katla volcano. Note the small cluster of earthquakes close the area where an small eruption took place in the year 1999. Copyright of this image belongs to IMO.

There has been some small cluster of earthquakes taking place in Katla volcano caldera. I am not yet sure what that means at the moment. However this might be clues to minor dike intrusions into Katla volcano caldera. But without more data, it is impossible to be sure on this detail at current time.

Last night there was an change in harmonic tremor on two SIL stations around Katla volcano. But due to high wind noise I am unsure what was going on. But it is possible that this was an small dike intrusion taking place close to Goðabunga part of Katla volcano, or this was an minor glacier flood that was taking place under the glacier. At current time I have no good idea what was going on.


The harmonic tremor on Smjörgil SIL station. The signal is unclear due to high wind noise. Copyright of this picture belongs to IMO.


The harmonic tremor signal on the Goðabunga SIL station. Due to high wind the signal is unclear and hard to see. Copyright of this picture belongs to IMO.

It is hard to know for sure what happens next in Katla volcano. But important signs can be found in earthquake patterns. But it is also important not to overlay broad interpret the data in the favor of an eruption taking place. As it is impossible to know for sure when Katla volcano erupts, and then how big. All we might get is an new small eruption like in July 2011. As Katla volcano can also have small eruptions like big ones.

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Harmonic tremor pulse in Katla volcano

Today there was an harmonic tremor pulse in Katla volcano. I am not sure when this harmonic tremor pulse did start. But I am guessing around 15:22 UTC or maybe around 16:00 UTC. It seems that this harmonic tremor pulse was small, considering the activity in July 2011 in Katla volcano (an minor eruption). This harmonic tremor pulse seems to have happened in the north part of Katla volcano, outside the caldera from my best estimates but might well be inside it in the north part of it. But it hard to be sure on that detail. From what I can tell, this harmonic tremor pulse does not appear on my geophones clearly. But it might have appeared on Hekla geophone poorly. But it is hard to be sure on that due to wind noise. When this is written the harmonic tremor pulse appears to be dying down. But there is still an possibly that it might pick up again or an new one might start without warning. It is impossible to know for sure how long this is going to stop after this harmonic tremor pulse. This harmonic tremor pulse is due to dike intrusion in Katla volcano at depth, so earthquakes might not happen until it reaches shallower surface in the crust. If the dike intrusion gets that far to start with.


The possible location of the harmonic tremor marked by the poorly located earthquake in Katla volcano. Copyright of this image belongs to IMO (Iceland Met Office).


The harmonic tremor on the Slysaalda SIL station where it is the strongest. But that means it is closest to this SIL station. Copyright of this image belongs to IMO (Iceland Met Office).


The harmonic tremor pulse on Goðabunga SIL station. The harmonic tremor pulse is weaker here then on Slysaalda SIL station. Copyright of this image belongs to IMO (Iceland Met Office).


The harmonic tremor pulse on Skrokkalda SIL station. One of the SIL station that have the most distance from Katla volcano area where the tremor pulse is taking place. Copyright of this image belongs to IMO (Iceland Met Office).


The harmonic tremor pulse can clearly be seen on Lágu Hvolar SIL station. Copyright of this image belongs to IMO (Iceland Met Office).


The harmonic tremor on Smjörgil SIL station, it is located in the flanks of Eyjafjallajökull volcano. This SIL station is close to Goðabunga SIL station. Copyright of this image belongs to IMO (Iceland Met Office).

What happens next in Katla volcano is hard to know. It all comes down to wait and see what happens next in Katla volcano. Eruptions in Katla volcano in January – February time period are not common, but due happen at times. So this harmonic tremor pulse might be an advance warning of what is to come. But that is just speculation on my part. It is impossible to know for sure what happens in Katla volcano until it happens.

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Earthquake swarm in Katla volcano, earthquake in Hekla volcano

Tonight at 21:13 UTC there was an earthquake with the size of ML1.2, it had the depth of 0.1 km. But that is about 100 meters. This is the second earthquake in Hekla volcano during that past three weeks (almost an month since last earthquake did happen in Hekla volcano). So far nothing more has happened. But that might change without warning.


The earthquake in Hekla volcano. It is the red dot in Hekla volcano. Copyright of this picture belongs to IMO.

Katla volcano

Today at 16:04 to 16:27 UTC there was an minor earthquake swarm in Katla volcano. The largest earthquake had the size of ML2.6, with the depth of 1.4 km. Like before this earthquake swarm was because of an dike intrusion into Katla volcano caldera. But this suggests that the unrest that started in Katla volcano in July 2011 is not over. But for the moment it continues at lower rate then before. But that might also change without warning at any time.


The earthquake swarm in Katla volcano. The earthquake in Hekla volcano can also be clearly seen on it. Copyright of this picture belongs to IMO.

It is impossible to know for sure what is going to happen next in both of this volcano. But it is clearly worth watching what is going on. The earthquake in Hekla volcano can clearly be seen on my Heklubyggð geophone, as it forms an clear spike on it, the web site can be found here. Same does the largest earthquake from Katla volcano earlier today.