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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)

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Katla volcano earthquake last night

Last night there was a earthquake with the size ML2.3 and with the depth of 1.3 km inside the caldera of Katla volcano. This earthquake might well be just part of the normal summer and autumn earthquake activity in Katla volcano. But at the moment it is hard to know for sure the difference at the moment.


Current area of activity in Katla volcano. It is mostly inside the caldera. Copyright of this picture belongs to Icelandic Met Office.


The ML2.3 earthquake in Katla volcano caldera last night. The P and S wave markers are unset. Picture Licence is Creative Commons.


The frequency spectrum of the Katla volcano caldera earthquake. As can be seen this earthquake has a lot of low frequency in it. Picture Licence is Creative Commons.


The Katla volcano caldera earthquake as it was recorded on my Hvammstangi geophone. It is quite unusual to record this small earthquake at this distance. This is filtered at 1Hz. Picture Licence is Creative Commons.


This earthquake here is from Goðabunga this morning. But Goðabunga is part of Katla volcano. But it is yet unknown if it is a volcano system on its own or not. The earthquakes from Goðabunga are different then the earthquakes from Katla volcano caldera, as can clearly been seen on this pictures. Picture Licence is Creative Commons.

Besides this minor earthquake activity. Everything remains quiet in Katla volcano at the moment. When that is going to change is impossible to know.

Blog post updated at 21:10 UTC.

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A ML3.7 (automatic size est.) earthquake happens on Reykjanes, close to town called Grindavík

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.

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Background noise compared to a eruption and other events

Here are few examples of how the tremor plots looks like if anything important is going on in Iceland.


Normal quiet tremor plot. Few earthquakes create spikes on it. But besides that everything is quiet. Copyright of this pictures belongs to Icelandic Met Office.


This is from the Grímsfjall volcano eruption in May 2011. On this tremor plot it can be clearly seen how much noise a eruption actually makes. The background noise just goes away soon as there is something going on. Copyright of this pictures belongs to Icelandic Met Office.


This is Skrokkalda SIL stastion on 12 July 2011. It can clearly be seen where the harmonic tremor goes above the background noise. Copyright of this pictures belongs to Icelandic Met Office.

It is quite clear. Besides earthquakes and some harmonic tremors that are different then this signals that I have shown here. Unless you see this on Icelandic Met Office tremor plot you can be sure that it is quiet in Iceland. Volcano eruptions make a lot of noise when they are ongoing, even the small eruptions make some noise that can be detected by the SIL network in Iceland.

Note: I might update this blog post on later date and put in more examples about the difference between background noise and a eruption.

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New pictures of Eyjafjallajökull Gígujökull glacier lava field

Rúv News has just published new pictures of Eyjafjallajökull volcano. The pictures are from Fimmvörðuháls lava field and the lava field that is in Gígujökull glacier. But in that area a lava flow did take place during the eruption. That lava field has not been explored before. According to the news, a moss has already started to grow on the new lava on Fimmvörðuháls. The Gígjökull glacier has already started to cover the lava field that did melt it during the eruption of 2010 in Eyjafjallajökull volcano.


From Gígjökull glacier. Picture from Rúv News. Copyright holder of this picture is Rúv.

The news of this can be found here. This is in Icelandic.

News from Rúv.

Undraveröld í Gígjökli (Rúv.is, Icelandic, Picture, Video)

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Earthquake swarms in Krýsuvík volcano, Tjörnes Fracture Zone and SPAR fracture zone (Kolbeinsey Ridge)

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.

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Earthquake activity in Katla volcano increases again

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.

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How donations help me II

This is a off-topic blog post.

The earlier background information can be found here.

The saving project for the next 14 or so months

After what I call a rather expensive (more then expected and more what I liked) August. I am going to freeze my spending for the next 14 or so months. That means I am going to limit my spending as much that I can do during this time. But that is until I move back to Denmark in February 2013. I have to spend some money on food, maintenance on my computer and all necessary stuff. But I am going to limit that as I can possible do. I just hope that nothing dies or fails computer wise during this period.

My debt paying down plan is running good at current time. I do not expect any problems with it, at least nothing that I cannot balance out in the budget during the paying down period. At least that is what I hope actually happens. But I have to wait and see what happens actually.

How the donation button works

This might be obvious. But I am going to write it down anyway.

The “Donation” button is a single donation. It is what you want to donate. It is a free range of what people want to donate. The “Subscribe” donation button is fixed at €10, but that is $14.17, 8.7GBP, 74.51 DKK, 93.29 SEK (current exchange rate, this is a estimate). It runs for 6 months and then has to be renewed. I did not want to last for 12 months or longer. I did not find it to be fair to the people how donate, as things change change a lot in 6 months. This option was for people how might want to donate regularly. But not a large amount each time they donate.

People how want to donate in other currencies the Euro can do so. I support SEK, DKK, USD, GBP. If requested I can add more currencies that I can support. But it has to be a currency that might be used every once in a while. I do not want to support a currency that is never used for a donations.

The income problem

As I have told people before. I just have my income from social welfare. Something that I am to get my self off with income from e-book sales when the time comes. But at the moment this blog and a new blog that I am going to create are my work and provide a little bit of income during the month. This extra income helps in that sense it allows me to pay down my debt faster. But I would not go as far saying it allows me to collect some money in the long run. But I am going to do my best with saving money during this winter, as I need to do if if I want to move back to Denmark.

It is also a problem in Iceland in regards to income how prices are going up in regards to food and other stuff. I do however not expect this to be too big of a problem during the next 14 months or so while I am living in Iceland. I just hope that I make it out in time before the economic mess starts in Iceland. If people want to talk about it, they can do so here on my main Icelandic blog where I write about this in English or Icelandic if they fancy Google Translate errors.

I hope that my income problems gets less annoying when I start to publish my e-books. But I plan to release few short stories in few weeks time. Those are not long stories and won’t be expensive. At least I hope for the best when it comes to e-book sales.

As always I thank you for the support that I get with donations. 🙂

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Earthquake swarm on the TFZ

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.

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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.