Few right and wrong things about geology in Iceland, part 1

I have seen many speculations on how geology works in Iceland. Some of it is good and based on observation and factual basic. Other however is nothing but speculation and far from anything based on factual evidence on how geology works in Iceland.

Few right and wrong things about volcanism in Iceland

Volcano interaction Status: Limited truth to this

Volcano interaction is something of a debated among scientists. But what is not debated is the interaction between volcanoes that lies far apart. That interaction is none by it’s nature. So while I have been seeing discussion in the comments here that there is some connection between activity between Hengill volcano and Hekla volcano. This is untrue. There is no connection between those volcanoes and never has been. The reason is simple. The volcanoes are far apart. They don’t even share the same magma source. But that is evident by the lava that comes from this two volcanoes. But Hekla volcano has mixed types of eruption sometimes. But Hengill volcano only has Hawaii styles eruptions (if not hit by water) when it erupts, in style with other volcanoes on the Reykjanes ridge rift zone.

The only real life examples of volcano interaction are from Bárðarbunga volcano and Torfajökull volcano. The reason for this interaction is quite simple and logical one. Bárðarbunga fissure swarm cuts right trough Torfajökull volcano. When magma travels south-east in the fissure swarm (it last happened in the 15th century) it can hit the magma inside Torfajökull volcano. When this happens there is a big bang in Torfajökull volcano. As the magma in Torfajökull volcano seems to be colder and more Intermediate (andesitic) [link, Wikipedia] in nature. But in Bárðarbunga volcano the magma is Mafic (basaltic) in nature. When the two magmas mix, it ends with a bang and eruption in both volcanoes. But normally the process that starts this is because there is a ongoing eruption in Bárðarbunga volcano. So when Bárðarbunga volcano. I would worry about that rather then anything else.

See, no connection at all between Hekla and Hengill volcano. Copyright belongs too this picture owner. Owner unknown to me.

Iceland is going to have VEI-8 eruption. Status: Not likely.

All volcanoes can do a VEI-8. But the thing is that they are just not likely to do so. As the size of the eruption is directly connected to the inflow of magma it is getting. In the case of Icelandic volcanoes the inflow just seems to be few magnitude too small to make a VEI-8 eruption. The largest VEI eruption known in Iceland was a VEI-6 eruption that took place in Bárðarbunga volcano in the year 1477 (?).

As for VEI-8 eruption. I am not expecting that type of eruption any time soon in Iceland.

Iceland is one volcano. Status: False.

The simple answer is no. The long answer is. Iceland has many volcanoes, not just one. So the answer is no to this.

Geology in Iceland is well understood. Status: False

Geology in Iceland is understood. But far from being fully understood. As it happens geology science is just starting to now understand what complex progress are taking place in Iceland. A lot have been learned. But a lot more needs to be learned about how geology works in Iceland.

Volcano eruptions comes in active cycles. Status: True

This has been observed by actual data. But volcano activity happens in periods of 80 to 160 years. With a quiet period of 50 to 90 years. But numbers are approximation. During the quiet time there are fewer eruptions and they are smaller (hint: Large eruption can still happen however during the quiet period). Last quiet period started in around the year 1870 and did not end until the year 1983. But that year there was a eruption in Grímsfjall volcano. But then Grímsfjall volcano had not erupted since the year 1954, but that break was 29 years long for Grímsfjall volcano.

This graph here also shows this clearly. But this is volcanism in Iceland during the years 1875 and to the year 1993.

Copyright holder unknown. Copyright of this picture belongs to this owner.

It is impossible to know for sure when the high peak in the current cycle is going to be be. But most geologist are estimating that to be sometimes from the year 2020 and to 2080 or about that. So the years ahead is going to be quite busy in Iceland in the terms of volcano activity.

I am going to write more right and wrongs about Icelandic volcanoes soon. But for now this is good enough.

Sources and other things.

Volcano-tectonic Interaction in the Hengill Region, Iceland during 1993-1998 (pdf)
Volcano geodesy and magma dynamics in Iceland (ScienceDirect)
Interaction between Continental Lithosphere and the Iceland Plume—Sr-Nd-Pb Isotope Geochemistry of Tertiary Basalts, NE Greenland
Tomographic evidence for a narrow whole mantle plume below Iceland (ScienceDirect)
Pdf document on Hengill volcano crustal deformation.
Magma (Wikipedia)
Volcano geodesy and magma dynamics in Iceland (pdf)

Earthquake swarm north of Langjökull glacier and volcano, new hole found in Selfoss town

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.

Possible minor eruption in Hamarinn volcano yesterday. Update on Katla volcano

There appears to be more in this new hydrothermal activity in Hamarinn volcano then at first sight. It seems that this actually might have a eruption in Hamarinn volcano (Bárðarbunga volcano). If this event is confirmed, this is the first eruption in Hamarinn volcano since the year 1910.

This also mean that there is a chance of more activity in this area in coming weeks or months. But when it might happen is impossible to know.

The new cauldrons are marked with a “X” on this map. Copyright of this picture belongs to Icelandic Met Office.

This eruption was really small and did just last for few hours. But it was able to melt a lot of ice and create rather large glacier flood from Vatnajökull glacier. If the activity resumes in this area this is going to repeat it self in terms of glacier flood.

Icelandic News about this event.

Innskot af kviku (Rúv.is, Icelandic)
Eldgos gæti hafa brotist upp við Hamarinn (Vísir.is, Icelandic, Pictures)
Fundu nýjan sigketil (mbl.is, Icelandic, Pictures)

Sigketill við Lokahrygg (Icelandic Met Office, Icelandic, Pictures)

Update on Katla volcano

Here is a short update on Katla volcano. There have been repeated short burst of harmonic tremors taking place inside the Katla volcano caldera. This harmonic tremor spikes have been small and they are hard to see on the harmonic tremor graph that Icelandic Met Office has on-line. Other then this it has been quiet so far in Katla volcano.

New harmonic tremor detected. But it is not from Katla volcano

Some other and unknown volcano dedicated to join the spotlight in Iceland by starting making it’s own harmonic tremor. I do not yet know what volcano this is. But most likely it is the Hamarinn volcano. But that is part of Bárðarbunga volcano.

Skrokkalda SIL stations 07:49 UTC this morning. The first harmonic tremor spike seen on that SIL station. Copyright of this image belongs to Icelandic Met Office.

Skrokkalda SIL station 19:09 UTC. The third harmonic tremor spike in progress when this graph was saved. Copyright of this image belongs to Icelandic Met Office.

I do not know what volcano is making this noise since there are no earthquakes. But I now find this most likely to be an dike intrusion somewhere close to Skrokkalda SIL stations. Other volcanoes that might be creating this harmonic tremor is the volcano Tungnafellsjökull volcano or the volcano that Skrokkalda SIL station actually is on top of.

But both of those volcanoes have been dormant for an long time now. So I find that to be unlikely, but not impossible. Until a earthquakes happens or something else that actually shows the area of activity in question. This is all just a guess work out in the blue.

Update 1: There is more going on there now then when this first did start. I did record an earthquake from this harmonic tremor around 00:30 UTC. This earthquake was extremely low period as can be seen on this picture.

This earthquake took place around 00:30 UTC on 13. July 2011. It is filtered at 1Hz and is extremely long period earthquake. This suggests that magma did create this earthquake. This picture is released under Creative Commons Attribution-ShareAlike 3.0 Unported License. See the Creative Commons Licence web page for more information.

Blog post updated at 01:02 UTC on 13. July 2011.

Something odd is going on at Krýsuvík volcano [speculation]

Please note! What goes below here are speculations based on what I am observing. Nothing might happen, but then again something might happen. We just have to wait and see what happens when it comes down to it.

I have been observing a slight change in the lower frequency band (0.5 – 1 Hz) at Krýsuvík SIL station. This change reminds me of a harmonic tremor of short. But it is not strong enough to appear clearly on Krýsuvík SIL station. But that SIL station is directly on top of Krýsuvík volcano. There have not been a lot of earthquake following this change in the lower frequency bands at Krýsuvík SIL station.

Picture from Icelandic Met Office web site. Copyright of this picture belongs to Icelandic Met Office. This plot was saved at 02:11 UTC on the 05.03.2011. The changes can be seen on 0.5 – 1Hz close to the end.

I am not sure what is going on. But there might be a small chance that this is a magma that is on the move. The second option might also be that a new hydrothermal area did appear close to the Krýsuvík SIL station. If this is magma, then a volcano eruption in the area is not far off (days, weeks, months?). But only time is going to tell for sure what is happening.

Other note: The activity in north Iceland and in the highlands are frost quakes. But it is extremely cold in this area of Iceland at the moment. More frost quakes can appear on IMO maps in the next few hours.

Good chance of Krísuvík volcano eruption in immanent future

I have been viewing data on Krísuvík volcano and what has been happening recently. Out of this checking I have come to a conclusion that a eruption in Krísuvík volcano is going to place in immanent future. When that might happen is impossible to know for sure.

Far as I know there is no written history on the last eruption at Krísuvík volcano that took place in 14th century. Because of this lack of historic witness of the last eruption in Krísuvík volcano it is impossible to know how the Krísuvík volcano is going to behave before it starts erupting.

It is my un-professional opinion that when a eruption starts in Krísuvík volcano we are going to see something like that took place in Krafla volcano when it erupts. Not exactly like Krafla volcano but something along those lines in eruption style. But Krísuvík volcano is going to have Hawaiian type eruption style when it starts erupting. Unless the eruption takes place under water. Then a Surtseyjan style eruption takes place while a water can get into the crater.

Please note that this is a theory that I am working on. It might work out in part or in full. But then again it might be completely wrong and not work at all. If the second option is true, then I am going to start again and make a new idea on what is going on at Krísuvík volcano.

Signs that a eruption in Grímsfjall volcano might be close

Over the past two weeks there have been signs appearing that a eruption might be close in Grímsfjall volcano. But a GPS station named Skrokkalda. This GPS station has started to move north, but this indicates that inflation has started in Grímsfjall volcano at full power. This did also happen at the same GPS station in 2004 before the eruption in Grímsfjall volcano that same year. But it is debated if this movement was created by ice or by a dike intrusion in Grímsfjall volcano. It is my just my personal opinion on this movement that takes place at the GPS station.

It currently remains to be seen if this northerly movement continues or if it starts to deflate again. So far this is the only indicator that Grímsfjall volcano is getting ready for a eruption. When this did happen in the year 2004 it was almost three weeks after this process started until a eruption took place. But then a glacier flood did trigger the start of the eruption in the year 2004.

For the moment the only thing to do is to wait and see what happens with Grímsfjall volcano. Nobody can tell how long the wait is going to be.

Are Esjufjöll volcano starting to inflate ?

I have been monitoring the GPS station at Grímsfjall volcano. After the earthquakes that took place in Esjufjöll volcano few weeks ago something interesting started to happen at that GPS station. It started to move in north direction.

Due to the location and lack of activity in Esjufjöll volcano there are almost none GPS stations around that volcano, and there are not many SIL station in this area. So getting insight into what is happening in Esjufjöll volcano is hard. But given the GPS station at Grímsfjall volcano it seems to that Esjufjöll volcano have started to inflate. It is hard to know exactly by how much at current time. But it appears to enough to have effect on the GPS station at Grímsfjall volcano.

This is given that Grímsfjall volcano it self is not having any inflation south of the GPS station on it’s own. At the moment it is hard to know what volcano is responsible for the northward movement. Only time is going to tell us the truth in that matter.

Grímsfjall volcano GPS data (automatic, Icelandic)