Volcano and earthquake activity in Iceland
A earthquake that had the automatic size of ML3.7 did happen at 22:14 UTC on the Reykjanes. This earthquake was only 2.6 km away from a town in called Grindavík. The earthquake was felt well in town according to reports that I got over Facebook.
The ML3.7 (automatic size) earthquake location. Copyright of this picture belongs to Icelandic Met Office.
So far no aftershocks have happened where the main earthquake took place. But that might change at any time.
In the last few days there has been good earthquake activity in TFZ (Tjörnes Fracture Zone). The largest earthquakes have been up to ML3.0 in size. But this earthquakes swarm have mostly been small and lasted for a short time.
Last night a earthquake swarm started in Krýsuvík volcano. This was just a normal tectonic earthquake swarm that normally takes place in this area on regular basic. From what I can tell. But it is impossible to know if this earthquake swarm was created by magma movement or not.
The earthquake swarm as it did appear on my Heklubyggð geophone. This picture is released under Creative Common Licence, see the licence page for more details.
The location of the earthquake swarm. Copyright of this picture belongs to the Icelandic Met Office.
This earthquake swarm took place in and close to a lake called Kleifarvatn. The largest earthquake in this earthquake swarm was a ML2.9 (automatic size). Currently the earthquake swarm is ongoing. But it has slowed a lot down since it started last night. At the moment, it looks like this earthquake swarm in Krýsuvík volcano is over for now.
Some earthquake activity was also on the south part of the MAR SPAR fracture zone, south and north of Kolbeinsey Island. The largest earthquake there was a ML3.0 (automatic data). Earthquakes this area happen often also. Like on the Tjörnes Fracture Zone.
Blog post updated at 23:38 UTC.
Blog post updated at 22:06 UTC on 16. August 2011. Fixed a error in it.
I was going to write about something else (TFZ and other earthquakes around Iceland in the last few days). But that just has to wait for a little longer.
It seems that Katla volcano earthquakes are increasing again. This increase appears to be similar to the increase in earthquakes before the glacier flood from the 9th to 17th of June and onwards until the glacier flood on 8th and 9th of July. The only difference now is that I am seeing this pattern earlier since I now know what to look for this time around when this is in its early stages.
How this is going to develop now is a wait and see process. But this might take as long time to get interesting as it did in June to July, to the event that ended with the glacier flood from Mýrdalsjökull glacier.
Current earthquake activity in Katla volcano. Copyright of this picture belongs to Icelandic Met Office.
It is also worth noticing that the earthquake activity is not as focused as it was in early June and in July. But I am fully expecting that to happen soon. But it remains to be seen if that actually happens or not.
The earthquake activity SSE in the Katla volcano caldera rim is still interesting. I do not know why it is taking place there. But if a eruption would take place at this location. There would be a short glacier flood and some period with volcano ash explosions. But after that it should be lava eruption in that location if it where to last long enough to remove all that water from the crater. But this is all just a speculation and nothing more.
For now. It is just wait and see what happens next.
There is currently a earthquake swarm taking place on the TFZ. This earthquake swarm appears to be rather small at the moment. The largest earthquake so far has been a ML3.2 according to the automatic earthquake list on Icelandic Met Office earthquake list.
There is no volcano activity connected to this earthquake swarm, as there are no volcanoes in this area off the coast of Iceland but there are volcanoes in part of what is considered part of TFZ. This area has its earthquakes from a slip faults. But they move in both north-east to north-west, but also in south-north direction in some cases.
The Tjörnes Fracture Zone. Copyright of this picture belongs to it’s owner. Picture found here.
Here is the latest earthquake image from Icelandic Met Office about this earthquake swarm.
Copyright of this picture belongs to Icelandic Met Office.
It is impossible to know how this earthquake swarm behaves. It is also known for the TFZ area that one earthquake swarm can start a new earthquake swarm nearby if a large enough earthquake happens. This happens sometimes, but not always. It is not a common thing to take place in the TFZ from what I remember about activity in TFZ.
I am going to update this blog post if this earthquake activity becomes something larger then it already is, or if a large earthquakes takes place in the TFZ.
This is a short update.
Langjökull glacier: Yesterday there was a minor earthquake swarm north of Langjökull glacier and volcano. This area did last time was last year when a good sized earthquake swarm did happen in this area, but last year it did start around this time of year and lasted until November. It remains to be seen if that happens now. So far all the data suggests that this earthquake swarm is just tectonic in nature. It also appears that earthquake swarms in this area start slowly with long breaks between them. So I am expecting more earthquakes there. Unless this has just been a single event with no repeats.
SISZ: On Selfoss town they have just found a new strange hole in the road. The opening of the hole is about 1.5 meter in size. But the depth is about 6 meters (guess?) and area that is hollow under the hole is few hundred meters (guess?) according to the news. It is believed that this did happen because of the SISZ Mb6.3 earthquake that did happen in this area in the year 2008.
Here are news about, with pictures of the hole.
Jarðskjálftahola á Selfossi (Rúv.is, Icelandic, Picture)
Hola myndaðist í jörðinni á Selfossi (Vísir.is, Icelandic, Pictures)
Katla volcano: I think that something might be about to start in Katla volcano. But that is just a speculation that I am doing now. I am far from sure about it. But it should be clear in few hours if something is happening in Katla volcano or not. I base my assessment on rather odd changes in the tremor plot. They are hard to spot, but still there and appears to be growing it seems. But I am going to check and see what happens in few hours time. This might be nothing. But only time is going to tell us that for sure.
Here is a short overview of the Hamarinn volcano activity this summer. From what I can gather in the current data this is most likely not over. During the past few days there have been at least suspected two minor eruption in Hamarinn volcano. But it hard to confirm it due to glacier that is covering this area.
This all starts on 12. July 2011 at 07:30 UTC with this event here.
The tremor spike on 12. July 2011 at 07:49 UTC. Copyright of this picture belongs to Icelandic Met Office.
When the clock is around 19:10 UTC the same day the tremor chart looks like this.
The tremor spikes are now three on 12. July 2011 at 19:09 UTC. Copyright of this picture belongs to Icelandic Met Office.
On the 13. July 2011 the tremor plot looks like this. But at that time the glacier flood had started and broken from the Vatnajökull glacier.
The tremor chart at 13. July 2011 at 01:10 UTC. Copyright of this picture belongs to Icelandic Met Office.
The tremor chart at 13. July 2011 at 12:59 UTC. Copyright of this picture belongs to Icelandic Met Office.
Then there was a short period of break when nothing interesting happened in Hamarinn volcano. That break did last until 16. July 2011 when a new, but smaller spike did appear on Skrokkalda SIL station.
The tremor at 16. July 2011 at 15:22 UTC. It is not fully clear what did happen at this time. But this was most likely a earthquake in Hamarinn volcano. But that is yet unconfirmed at this time. Copyright of this picture belongs to Icelandic Met Office.
Then there is a new break that lasts until 1. August when a earthquakes happens deep under Bárðarbunga volcano. But the deepest earthquake had the depth of 25.2 km. But it is also important to notice this earthquake that took place on 13. July 2011 and it is from Hamarinn volcano.
The earthquake from Hamarinn volcano. This picture is released under Creative Commons licence. Please see licence web page for more details.
On the 3. August 2011 around 02:00 UTC a new harmonic tremor spike starts to be visible on Skrokkalda SIL station.
The tremor plot at 01:55 UTC on 3. August 2011. Copyright of this picture belongs to Icelandic Met Office.
This day two minor harmonic tremor happens. A change in Skaftá glacier river is noticed. That is higher conductivity and slightly more water. It was announced in the news that a Skaftá glacier river flood was about to start from the eastern glacier cauldron that is formed above the Hamarinn volcano. Today however that does not seem to be the case. As no glacier flood has taken place so far.
Today (5. August 2011) there was a new harmonic tremor spike on Skrokkalda SIL station. It did follow the same pattern as before. It started and lasted for about 20 to 60 minutes or about that long.
The tremor chart 5. August 2011 at 17:38 UTC. Copyright of this image belongs to Icelandic Met Office.
So far today only one harmonic tremor has been detected. But given the past experience that is unlikely to hold for a long time now. But it is impossible to know when a new event starts or how big it is going to be.
The original event on 12. July 2011 did create new cauldron in the glacier. This map from Icelandic Met Office shows the location of those new cauldrons. But it has been marked with a star on the map. The coloured dots are earthquakes in this area over the past few years.
Map of the area that is currently active in Hamarinn volcano. Copyright of this image belongs to Icelandic Met Office.
Given the current data I am expect a full scale eruption in this area soon. When is hard to know for sure. But until that happens there are going to be more smaller eruptions in this area. I do not know why there is a lack of earthquakes following this events. I cannot explain it. But because of that this can only be seen after it has started on the tremor charts.
Here is the earthquake that took place in Hekla volcano this morning. This earthquake was small, just ML2.02 with the depth of 4.8 km. Because of how close this earthquake was to my geophone at Heklubyggð it did appear clearly on it.
The earthquake at Hekla volcano this morning. This picture is released under Creative Commons License, see License web page for more details.
No aftershocks where recorded after this earthquake and nothing suggests that a Hekla volcano is about to erupt at present time. But that can change without warning at any time.
It appears that a earthquake swarm has started on the Reykjanes Ridge. This earthquake swarm appears to have started with a earthquake that is ML3.6 to ML4.0 in size or larger. But I don’t think it is a Mb5.0 in size. On the earthquake list on the Icelandic Met Office web site there are several ghost earthquakes. But I did just record one earthquake on my geophones.
The current area of activity on the Reykjanes Ridge. Copyright of this picture belongs to Icelandic Met Office.
This looks like a normal earthquake swarm on the Reykjanes Ridge. So far nothing suggests that this means a eruption is about to start in this area. But that might change without warning since this is a volcano area.
I am going to update this blog post if there are any more strong earthquakes on the Reykjanes Ridge.
At 02:06 and 02:07 UTC there where interesting earthquakes in Bárðarbunga volcano system. What makes them interesting is that fact they did happen at 0.6 km depth one of them. But this area did see some volcano related activity (speculated) earlier this summer, that did result in large glacier flood. But it has been suggested that a minor eruption took place there around 10. July 2011.
The two earthquakes can be seen as spikes at the end of this tremor plot from Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.
What makes this earthquakes so interesting is that they seem to have a low period component in them. But it was seen on the Kálfafell SIL station, and other SIL station that was decent distance from the source of the earthquake.
The two earthquakes can be seen as spikes at the end of this tremor plot from Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.
Currently there is nothing that suggests that a eruption is about to start in this area. But that can change without warning given the current status of Hamarinn volcano system.
There has been a minor earthquake swarm in Katla volcano today. This earthquake swarm started around 09:00 UTC and lasted with breaks until 14:39 UTC. The largest earthquake in this swarm was ML1.7 with the depth of 3.5 km. Following this earthquake swarm there was a small harmonic tremor spike seen on few SIL stations around Katla volcano. It is unknown at this time if there has been a small glacier flood taking place. But if that is the case, it should be known in the next few hours if that is the case or not.
The earthquake swarm in Katla volcano caldera. Copyright of this picture belongs to Icelandic Met Office.
The harmonic tremor spike can be seen on this SIL station. It is located close to the end of tremor plot. Copyright of this picture belongs to Icelandic Met Office.
The harmonic tremor spike can be seen on this SIL station. It is located close to the end of tremor plot. Copyright of this picture belongs to Icelandic Met Office.
This harmonic tremor is small, but larger then last harmonic tremor that took place in this are about one week ago (far as I can remember). Currently there is nothing that suggests that eruption is imminent. This is just earthquake activity in the same place as it has been for the past five or so weeks.
Sorry for the short blog post. I have gone sick with some cold. No advice needed on how to get rid of it. That is going to take few days on it’s own.