Day: November 7, 2011

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Harmonic tremor pulse in Hamarinn volcano

The harmonic tremor in Katla volcano seems to be over. It lasted only short duration after the earthquakes it seems. At least I cannot read anything else out of the data from the SIL station around Katla volcano.

But the harmonic tremor in Hamarinn volcano (part of Bárðarbunga volcano system) seems to be ongoing, as before there is little to no earthquake activity following this harmonic tremor activity. I have no idea why that is. But following this harmonic tremor there was one earthquake with the size ML1.9. But with extremely poor location and size measurement. So the size and depth are subject to a change.


The earthquake in Hamarinn volcano at 16:35 UTC on 7 November, 2011. Copyright of this image belongs to Iceland Met Office.


Harmonic tremor in Hamarinn volcano at 16:44 UTC on 7 November, 2011. Copyright of this image belongs to Iceland Met Office.

Currently the harmonic tremor pulse in Hamarinn volcano is ongoing. So far the harmonic tremor pulse has not reached the level that suggests a eruption is about to start in Hamarinn volcano, as did happen in July this summer (year 2011). But it worth keeping watch on this event in Hamarinn volcano. As more might be coming from that volcano. But its eruption pattern is undocumented so far, as there have been few to none eruptions in Harminn volcano in the 20th century in Iceland.

Update 1: The weather in this area is quite bad from what I can tell. But so far it does not seems to have any effect on the SIL stations. At least I do not see any weather pattern above the normal so far.

Update 2: There seems to have been a minor eruption in Hamarinn volcano. The harmonic tremor looks like that now. But that is almost the same tremor signal that was in July this summer when a minor eruption took place in Hamarinn volcano.


A clear sign in my opinion that a minor eruption took place in Hamarinn volcano. This activity might continue as it did in July. Copyright of this image belongs to Iceland Met Office.


The harmonic tremor sign can also been seen from Grímsfjall SIL station. Not as clear, as this is a small event. Copyright of this image belongs to Iceland Met Office.

A glacier flood should be expected from this event in the next few hours. At least I am assuming that given the glacier cover in the area. It is also a risk that this eruption is going to continue for the next few hours and drop off between as it did in July.

Blog post updated at 16:55 UTC on 7 November, 2011.
Blog post updated at 17:06 UTC on 7 November, 2011.

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Harmonic tremor pulse in Katla volcano

This just started few moments ago so I waiting on how this develops. But there is a harmonic tremor spike in Katla volcano.

The harmonic tremor in Katla volcano started with a small earthquake swarm. This is more then just minor event it seems. But at this moment it is hard to know how this is going to develop. But next few hours are going to give clear picture of what is going on in Katla volcano. There is a bad weather in the area, but that makes the observation of what is going on more difficult then in good weather.


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


Harmonic tremor pulse in Katla volcano at 16:00 UTC on 7 November, 2011. Copyright of this picture belongs to Iceland Met Office.


Harmonic tremor pulse in Katla volcano at 16:00 UTC on 7 November, 2011. Copyright of this picture belongs to Iceland Met Office.


Harmonic tremor pulse in Katla volcano at 16:16 UTC on 7 November, 2011. Copyright of this picture belongs to Iceland Met Office.

What happens next is impossible to know for sure. But watching what is happening in Katla volcano is the only thing that can be done for the moment. No more earthquakes have happened so far in Katla volcano (at the time when I write this). The harmonic tremor pulse was detected up to Skrokkalda SIL station. But also on Grímsfjall SIL station. There is a harmonic tremor pulse also taking place in Hamarinn volcano, more on in a little bit. This harmonic tremor pulse is because of dike intrusion is taking place in Katla volcano. It is impossible to know how big it is currently.

Blog post updated at 16:26 UTC on 7 November, 2011.

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General update for Katla volcano and El Hierro voclano

This is a general update for Katla volcano and El Hierro volcano.

Katla volcano, Iceland

During the weekend there was a minor dike intrusion into Katla volcano caldera. The largest earthquake in this earthquake swarm was a ML2.1 with the depth of 1.4km. This is among the smallest earthquake swarms in Katla volcano since activity started to increase after the small eruption in July 2011. The reason for this earthquake swarms in Katla volcano are dike intrusions (wiki). Sometimes following this are small glacier floods from Mýrdalsjökull glacier that is on top of the caldera. But that does not seems to have this time around, or the last time there was a dike intrusion in Katla volcano (few weeks ago).


The earthquake activity in Katla volcano during the weekend. Copyright of this picture belongs to Icelandic Met Office.

El Hierro volcano, Canary Islands, Spain

The eruption in El Hierro volcano continues as it has been doing for the past four weeks (almost). But the chance of a new island forming has grown somewhat in the past few days. The main reason for that is that eruption did gain some strength during the past two weeks. The increased strength in the eruption was due to a new injection of magma into El Hierro volcano. Both at the main magma sill and what seems to be a new magma intrusion into El Hierro at depth. That magma has so far not been able to reach the surface and remains at the depth of 20 km or so. But there also seems to be some dike intrusion activity been taking place in the same area, as more magma is injected under El Hierro volcano North West of the town of Frontera (IGN name information).

For that reason the risk of new eruption vents open up in this area is high in my opinion and is going to remain that during this eruption. But it remains to be seen if a new eruptions vents open up in this area. But that depends on the amount of magma that is currently injecting into El Hierro volcano at depth. It is impossible to know for how long new magma is going to get supplied into El Hierro volcano. But so far this process has been ongoing since July, so that is already five months (or about that) that new magma has been flowing into El Hierro volcano.

The formation of new Island off the coast of El Hierro Island is now a real chance. As the erupting vent has build up close enough to the surface of the water to start the Surtsey Island process. That process in it self is going to take few weeks to complete, at least until the crater no longer gets water into it. When the water can no longer into the crater the eruptions turns to lava fountain eruption. A Hawaiian style of eruption to be exact. That progress is going to remain to the end of eruption. But this is only going to happen if the eruption lasts long enough to build a small Island off the coast of El Hierro Island. So far that remains unseen. However the chance for this to happen is good in my view.

There is also worth noticing that this eruption is a bit variable in eruption strength. This can clearly be seen on the harmonic tremor plots that can be viewed online from El Hierro volcano. This is normal, as the flow of magma from inside El Hierro volcano is not stable and can change suddenly. The risk of new fissures to open up without warning remains high in the area around the current eruption vent is also high. The new fissure have the risk of opening up without any earthquakes and warning. To some extent this has already happened during this eruption. But I am not sure the new eruption vents did stay erupting for a long time. This is however most likely to repeat it self regularly during this eruption.


The harmonic tremor in El Hierro volcano on 7 November, 2011 at 09:32 UTC. Copyright of this picture belongs to Instituto Geográfico Nacional.

Off topic: Small apology

Here is a small apology to my readers. I have been a little bit under the weather in past few weeks. There are many reasons for this. But the biggest one is that my plan to live in Denmark failed this summer. But the chance of me moving back to Denmark has lifted my mood again. But I also found that playing computer games helps me dealing with my current status a bit. Because of this under the weather issue. My blog post have not been that good in my view. For that I want to apology. I can’t promise that this won’t happen again while I am living in Iceland. It is also a factor that the darkest time of the year never goes well with me (Mid October to early March).