Month: August 2011

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Minor harmonic tremor in Katla volcano

There seems to have been minor harmonic tremor in Katla volcano this evening. This harmonic tremor seems to have started after a ML0.7 earthquake with the depth of ~3.7 km did happen inside the Katla volcano caldera. Last harmonic tremor spike did take place on the 24th of August according to the tremor plot on Icelandic Met Office web page.


Harmonic tremor mixed in with the earthquakes from Katla volcano on this tremor plot. Copyright of this image belongs to Icelandic Met Office.


Here is the harmonic tremor that I see on the tremor plot. It is the second spike. But the first spike is actually a earthquakes that did happen earlier today. Copyright of this image belongs to Icelandic Met Office.


This harmonic tremor can also be seen on this SIL station clearly. Copyright of this image belongs to Icelandic Met Office.

On other SIL stations around Katla volcano the signal is not so clear. But this is really a small event and unlikely a pre-eruption event. But it is hard to know it for sure, as Katla volcano has done this before and there was no eruption following this type of events. All that can be done now is to wait and see what happens next. It is also important to notice that Icelandic Met Office has not confirmed this harmonic tremor spike yet.

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Iceland government to increase monitoring and research into Iceland volcanoes

Iceland government did approve today to increase funding for research into Iceland volcanoes. But this is also part of a plan for a risk assessment for volcanoes in Iceland. But it is expected that this research is going to take 15 to 20 years. Funding has already been increased to Icelandic Met Office by grands from ICAO (among other I think, but I do not have it confirmed). But this is a direct response to the fact that Eyjafjallajökull volcano and Grímsfjall volcano have erupted in short time span (11 months apart).

But the Icelandic government is expecting a eruption in Grímsfjall volcano every two to seven years. But it is also expecting eruptions in Bárðarbunga volcano following this increased activity in Grímsfjall volcano. But eruption period often follow in Bárðarbunga volcano when activity increases in Grímsfjall volcano.

First step of this research is going to take three years to finish. But the news does not say what they are going to cover in this research. This risk assessment is done by the standards of U.N and WMO.

Icelandic News about this.

Hefja vinnu við hættumat fyrir eldgos – tekur 15 til 20 ár í heildina (Vísir.is, Icelandic)

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Earthquake close to Hekla volcano. A earthquake swarm in Katla volcano

This has been a busy weekend in earthquakes, more then I was expecting. Here is a minor write up on the activity so far.

Hekla volcano:

A ML2.4 earthquake did happen close to Hekla volcano at 07:30 UTC. Depth of this earthquake was 3.7 km. The earthquake did happen on earthquake fault line that was created in a large earthquake in the year 1912. This fault line has been known since then and is well documented.


The SISZ earthquake this morning. This picture is released under Creative Common Licence. See Licence web page for more details.

Katla volcano:

Two new earthquake swarms took place in Katla volcano today. This earthquake started around 09:30 UTC this morning. Most of the earthquakes where smaller then ML1.0 in size. The depth was around 5.5 km on average. The largest earthquake was ML2.3 in size, with the depth of 5.5 km. That earthquake swarm was in Goðabunga area of Mýrdalsjökull glacier (Katla volcano). But here was also a minor earthquake swarm inside Katla volcano caldera. But in that earthquake swarm the earthquakes there where even smaller, most of those earthquake didn’t reach the size ML1.0. The earthquake swarm in Goðabunga area in Katla volcano might be due to dike intrusion in that area. I do not know if this might be something else. But given the data, this is the most likely the reason for this earthquake swarm in this area. The earthquake swarm did stop at 12:47 UTC. After that everything has been quiet so far.

Few earthquakes also did happen SE part of the Katla volcano caldera. But there have been earthquakes in this area since July. But this activity did start soon after the glacier flood from Mýrdalsjökull glacier.


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

All the earthquake swarms of today in Katla volcano, also the single earthquake close to Hekla volcano.

Icelandic news about this activity.

Mikið um smáskjálfta nærri Mýrdalsjökli (Vísir.is)
Jörð skelfur nálægt Hellu (Rúv.is)

Other: Short announcement. I have finally figured out how I am going to have my writing schedule. But my working period is going to be from 1. September to 1. June every year. This also means more activity on this blog and my other (Icelandic) blogs. During the summer time there is going to be reduced activity on all my blogs. But if something happens during the summer in earthquakes and volcanoes. I am going to write about it anyway or soon as I can do so.

Also note that I have started school to finish basic in electronic (house electronics and other basics in electronics). So I am busy during the day (most days). So my response might be slower then normal if anything happens in Iceland with earthquakes or volcano activity.

Other #2: I am having minor issues with uploading the gif images from my earthquake computer at the moment. So that is currently being done by the remote geophone computers at the moment. Because of this, there is no red colour if a large earthquakes happens in Iceland or close to a geophone station that I have up and running.

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Earthquakes in Öræfajökull volcano

I do not have a time for long blog post about this at the moment. But here is a short overview of earthquake activity in Öræfajökull volcano.

Since the year 1991 there have been total of three earthquake swarms (with the one in last week) in Öræfajökull volcano. The two earthquake swarms where in the year December 2005 and in September 2008. Total of 70 or so earthquakes have taken place in this earthquake swarms. But only 30 or so earthquakes in the main crater of Öræfajökull volcano.


Earthquake activity in Öræfajökull volcano between the year 1991 and to 2011. Copyright of this image belongs to Icelandic Met Office.


Earthquakes inside the main crater of Öræfajökull volcano from the year 1991 to 2011. Copyright of this image belongs to Icelandic Met Office.

All pictures are from here.

Currently the earthquake activity in Öræfajökull volcano is quite low. So I am not expecting anything for a long, long time now. The reason why earthquakes are taking place might be new magma. But this also might be due the glacier and pressure changes on the rock because of that. But I find the later idea less likely then the first one. But it hard to know for sure at the moment what actually is the real case now.

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The importance of good science in geology (and other fields too)

I am not going to make this a long blog post.

I know that many of you find that I have been unfair when it comes to deal with certain ideas about geology and how it works. The truth however is that this was a lot more then just a idea, or a hypothesis. The claim was that “evidence” had been found for the claim to support. But from what I did see, no evidence where provided in support of the claim. To to be fair, it was sad that this idea might be wrong and wrong it was in my opinion.

This is what I call bad science. It is something that is not going to work and is never going to. The scientific method (wiki) is well established way of proofing claims and ideas.

For instance, all that I do in terms of geology and other fields of science fall all under this process. If I fail it is a important step, because it at least gave me a result to work with. When doing science, it is important to life with the fact not everything that is done is going to work up, or even get that far before it fails so spectacular that they did notice in the next lab over.

I do not dismiss everything that I read. But I am going to dismiss it if no evidence is provided with the claim in question. I my self is working on few ideas, that I have at least started from start up around 40 to 50 times on times. Just because it failed my test and did not fit the data that was observed.

This is how progress is made. With hard work and good scientific method. What is not progress is Pseudoscience (wiki) that in fact return nothing in the short and long term. I have for too long seen this happens on the internet and I am not going to let this happen to any of my blogs that deal with science topics (including this one here. It is a slow, slow blog).

Ideas are good and all that. Just tell the world if you have any data or not when you put your idea forward.

I also want to point out this two articles here. They are not science in them self. But they might explains one or two things about why I am strict on this matter and with the comments. But I want to keep this blog clean and good for all my readers.

5 Ways to Stop Trolls From Killing the Internet (Cracked.com)
Internet Argument Techniques (Cracked.com)

Thanks for the understanding.

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Few points about Iceland geology

Here are few points about geology in Iceland (just because I cannot sleep at the moment). This is also a offshoot of this blog post here.

The basic thing that needs to be known about Iceland is the fact that it is just a island over a hot spot. In every other terms it behaves as expected by a volcanic island on a rift zone. There is a lot known about Iceland geological features and volcanoes. But there is also a lot unknown at the moment. There is nothing mysterious or strange about that. We just don’t know this at the moment, but in the future we hopefully are going to know this. As each eruption or earthquake swarm teaches us more about Iceland and how it works.

I have seen a lot of wrong things about geology in Iceland on this blog in past few days. For instance the claim that energy travels trough a fault zone with N-S bearing (mostly). The volcanoes in question where Hengill volcano and Hekla volcano. This volcano do not exchange energy over SISZ. It simply just does not happen, as law of nature does not allow for it to happen. The following natural laws prohibits this energy transfer (and there is no way around it), Laws of thermodynamics, Inverse-square law, Conservation of mass, Conservation of energy, Momentum, Angular momentum and whole a lot of other physical laws that apply in nature.

I know one of two thing about physics too. As I fully apply that when I am considering what a volcano or a earthquake swarm might be up to in Iceland.

The evolution of Iceland during the past ~20 million years is also a factor in this. As there are many fully formed rift zones, but there is also a lot of failed rift zones in Iceland. There might even be new failed rift zones being formed today. But it impossible to know that for sure at given time. Since we have no way of knowing what is “new” and what is “old”. Research into this matter is going to shed some light on it. But that might take years of hard work of scientists for years to come.


The basic evolution of Iceland from 15milyr ago until the today. Copyright of this image belongs to its owner.


This is the best picture that I know of what they think is the Iceland hotspot. Copyright of this image belongs to its owner.

There is also the thing about the crust in Iceland. But it is believed that part of it might be from a old continent. But majority of it is currently covered with newer layers of rock and sediments. But studies have also suggested (or proved) this. The following papers can be read on this subject.

Older crust underlies Iceland (pdf)
Continental basement under Iceland revealed by old zircons
Continental geochemical signatures in dacites from Iceland and implications for models of early Archaean crust formation (ScienceDirect)

This in part explains the difference in crust thickness when it comes to Iceland.


The thickness of the crust in Iceland. Copyright of this image belongs to its owner.

All pictures above are from this study into the Iceland mantle plume (they are trying to disprove it existence). Iceland & the North Atlantic Igneous Province

Here is a different map of Iceland volcanoes, fissure swarms and age of the lava fields.


Iceland and its volcanoes. Copyright of this image belongs to its owner. This picture is from this web site here, Post-glacial rebound of Iceland during the Holocene Click on the picture to get full size.


Similar map. But in colour. Copyright of this image belongs to its owner.

I hope that this clear few things up about Iceland and how it works and might work. Since we are still learning and there is a lot of things that we do not know about how Iceland actually functions. But me and professional geologists and scientists are doing there best to learn about how Iceland works.

If there is a claim about Iceland that just sounds crazy, it probably is crazy and not based in any actual fact about Iceland and the geology that makes up Iceland.

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Minor earthquake swarm in Öræfajökull volcano

Since early this morning there has been a minor earthquake swarm in Öræfajökull volcano. This earthquake swarm is so far just minor one, with the largest earthquake being ML2.0 at 4.3 km depth.

This earthquake swarm is most likely due to magma injection into Öræfajökull volcano. But this volcano is normally quiet and almost never has any earthquakes. But that has been changing during the past few years, but earthquake swarms have been getting more common in Öræfajökull volcano. Something that is in fact a big change from few years ago when no earthquakes where recorded from Öræfajökull volcano.

This increased activity in Öræfajökull volcano seems to be happening at the same time as there is increased activity in Esjufjöll volcano. The two volcanoes are not connected. But this might suggest a more inflow of magma under the general area. But that is just a speculation, based on rather limited amount of data.


Öræfajökull volcano is located to the south end of Vatnajökull glacier. Copyright of this image belongs to Icelandic Met Office.

The earthquakes in Öræfajökull volcano have been taking place in the main crater of the volcano. But it is important to know that currently there is nothing to suggest that a eruption is imminent in Öræfajökull volcano or in Esjufjöll volcano.

Interesting reading material on Öræfajökull volcano

The 1362 AD Öræfajökull eruption, Iceland: Petrology and geochemistry of large-volume homogeneous rhyolite (pdf)

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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.