Category: Rift Zone

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Earthquake swarm north of Kolbeinsey Island

During the night (on 15.12.2012) there was a swarm of earthquakes far north of Kolbeinsey Island. The distance from Kolbeinsey Island is about 100 to 200 km. What exactly is taking place at this location is impossible to know for now. Since this is far from Iceland and the SIL network. Last eruption is believed to have taken place around this area back in the year 1999, or at least there was an large dike intrusion at that time. What did happen exactly is not known.


The earthquake activity north of Kolbeinsey Island at midnight (00:00 UTC) 15.12.2012. Copyright of this image belongs to Icelandic Meteorological Office.


Earthquake activity at 09:00 UTC this morning (15.12.2012). More earthquakes have taken place since midnight. Copyright of this image belongs to Icelandic Meteorological Office.

There is a chance of more earthquakes in this area. It can also be expected that not all earthquake activity in this area is being detected by the SIL network. Due to distance, weather and ocean activity.

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Earthquake swarm on Reykjanes Ridge last night (16.09.2012)

Last night there was an earthquake swarm on Reykjanes Ridge. Possibly on one of the volcanoes that are in this area of Iceland. The earthquake swarm lasted for several hours. Strongest earthquakes in this swarm had the magnitude of 3.5. With the depth from 23 km and up to 0.3 km. Strongest earthquakes in this swarm where visible on my geophone network.


The earthquake swarm on the Reykjanes Ridge. Copyright of this image belongs to Icelandic Meteorological Office.

Last earthquake swarm in this area was on 8. February 2012. There was also earthquake activity deep on the Reykjanes Ridge. With two earthquakes that did get the magnitude 4.4 (EMSC) at 12:51 UTC. The second earthquake took place at 14:30 UTC and had the magnitude of 4.4 (EMSC). This earthquake activity is far enough from land that only the largest earthquakes are detected.

But there seems to be a lot of earthquake activity both south and north of Iceland (Jan Mayen earthquake activity). But this not connected activity as such. But it is known that activity on Reykjanes Ridge happens in jumps. It is an question if such time has come that an new activity episode is about to start on the Reykjanes Ridge. But last major episode in activity on the Reykjanes Ridge ended about 671 years ago. But there is one eruption documented off the coast in the year 1926 according to Global Volcanism Program. That activity did last for 4 days or so.

I am not sure what is going to happen next on the Reykjanes Ridge. But I am going to report it best to my ability. With the best information that I can get when the time comes.

Icelandic news about this earthquake activity

34 skjálftar frá miðnætti (mbl.is, Icelandic)

Blog post updated at 02:47 UTC on 17.09.2012

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Old rift zone in Iceland

Here are two pictures of an old rift zone in Iceland. This rift zone was active until about 7 million years ago or so. This cliffs that I show here on this picture are from this old rift zone. It was volcanic long time ago. But not any more. This area however holds an good amount of unknown fissures and fault lines that might become active one day and create earthquakes in this area. But the years that I have been in this area I have never felt an earthquake. But I have recorded earthquake somewhere in this area. But it was an minor one. Less then ML1.5 in size. This area also used to be under ocean for several million years before it became dry land.


This is the old rift zone that was active until 7 million years ago. Click on the picture for full size. This picture is released under Creative Commons Licence. See the licence page for more details.

There is still an chance of this area to get new volcanoes in far future. Like did happen on Snæfellsnes. But this rift zone did pass trough there also. In this old rift zones there are several old volcanoes. I have covered them before on this blog. But that blog post can be found here.

More articles on this area

The Iceland Hotspot (academic.emporia.edu)
Iceland 2003 Keck Junior Research Project Geology of an Abandoned Oceanic Rift: The Skagi Area, North-Central Iceland (people.usd.edu)

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Earthquake swarm north of Jan Mayen Island

This blog officially also covers Jan Mayen Island north of Iceland. But since the Jan Mayen Island is uninhabited, activity there is not on the top priority list and I do not mention the Jan Mayen area as such because of this.

Yesterday (15.01.2012) there where two earthquakes detected by EMSC north of Jan Mayen Island. This earthquakes happened in the rift zone that is in this area. The largest earthquake had the size Mb4.9 with the default depth of 10 km. The smaller earthquake had the size Mb4.2 with the default depth of 10 km.

This area has the depth of around 2 km where it is shallowest (mountain peaks) so it is impossible to what is going on. But this is most likely tectonic earthquakes rather then volcanic earthquakes that are taking place in this area. But due the distance from populated areas and any seismometer networks only the largest earthquakes are detected when they happen. Norway National Seismic Network can be found here, they have some better resolution of earthquakes in the Jan Mayen Island then EMSC.

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Special report: New eruption vent (or vents) might have opened up in El Hierro volcano eruption

The current tremor data now suggests that a new vent or vents have opened or are about to open up just outside north-west coast of El Hierro volcano. The depth where the main earthquakes have been taking place is about 100 to 300 meters (but might be more). So far the largest earthquakes to take place in this area was a ML3.9 with the depth of 22 km. What is important in this is not the fact that the earthquakes are at great depth. But also the fact that a more shallow might not take place. As that was not the case when the eruption started in El Hierro on 10 October, 2011. It is unlikely that there is going to be any shallow earthquake activity before a new eruption vents opens up. As that was not the case on the 10 October, 2011 from what I can remember.


Current harmonic tremor in El Hierro. So far there has not been much change in harmonic tremor as can be seen here. But that can change without warning. Copyright of this picture belongs to Instituto Geográfico Nacional.

I am not sure how strong earthquake this area can make. But I am guessing that it might well be in the upper Mb5.5+ range. The earthquakes that are now taking place are due to magma injection. Not a tectonic one. There is a difference between the two. But this rifting in El Hierro might trigger a earthquake close to El Hierro Island in near future, that earthquake would be a tectonic one. Not a earthquake created by magma movements.

So far the new vents are still unconfirmed. But there are signs in the harmonic tremor data that new eruption vents might be opening up or have already opened up. But at this moment I am waiting for a confirmation on this actually taking place. That is going to take a few hours, given the experience so far.

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Special report: Update 6 on the eruption in El Hierro, Canary Islands, Spain

Special note: Please notice that my (personal) watching system is also going to include the mainland of Spain (mainland Spain has two volcanoes that I am aware of, along with some earthquake activity) when I change it next month, along with Canary Islands. Everything else is also going to be a subject to a special reports if the event is important enough. That is not always going to be case however. But I am going to post more details on this in the beginning of next month.
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Little seems to have changed in the eruption of El Hierro since my last update on it. That was on 19 October, 2011. Harmonic tremor is constant, but appears to have dropped a little in the past few days. But with the fluctuation that is often increases again before it drops down again. This means that the eruption is ongoing, but is loosing power to continue at current eruption vent. This was not unexpected. This has however not slowed down inflation in El Hierro from what I can gather on GPS data on El Hierro.

As the current eruption vents close down it seems that earthquakes have started again under El Hierro. But the earthquakes have the depth from 28 km and up to around 5 km. This strongly suggests that new magma is entering under El Hierro and is again increasing the pressure inside the El Hierro magma sill (or chamber, but note that El Hierro does not have a stable magma chamber it seems). This increases earthquakes while the magma does not have any good path up to the surface. When a new path for the magma starts to form again, a large earthquake swarm is going to take place in El Hierro. It is not going to be anything bigger then already has taken place in El Hierro already. With the largest earthquakes going up to Mb5.0 in size. That is at least my opinion.


All the earthquakes that have happened in El Hierro since magma intrusions started in July 2011. This pictures clearly shows in my view the amount of magma (in terms of size, not volume) that is under El Hierro at the moment. As it is marked on the outer layers by the earthquakes. Copyright of this picture belongs to Instituto Geográfico Nacional.


The harmonic tremor in El Hierro at midnight on 21 October, 2011. As can be seen, it fluctuates a little bit. Copyright of this picture belongs to Instituto Geográfico Nacional.

The major risk in the current eruption cycle of El Hierro is the risk that new eruption vent is going to open up nearby a human population without warning. But El Hierro has a lot of cinder cones from earlier eruption cycles. That creates the risk that a new eruption vent is going to open up on dry land without warning. But it is impossible to know when and where that might happen.

Claims that this eruption in El Hierro is going to create tsunami due to landslides are false and have no basic in fact or reality. As landslides are unlikely to happen in this eruption episode or if a eruption happens on dry land.

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A ML2.7 earthquake in Skagafjörður rift zone (mostly extinct one)

This earthquake is a odd one. But it is rare that earthquakes happens in this are of Iceland. But it is not unheard of. As there have even been small earthquake swarm in this area few years ago (2 or 3 years ago I think). This area is part of Skagafjörður rift zone (pdf file) (also known as Skagafjörður Volcanic zone), but that is believed to be a failed rift zone that formed in about 1.7 million years ago. Just around when current eastern rift zone started to form in Iceland.


The ML2.7 earthquake is the left corner of this image, a bit far away from TFZ earthquake zone. Copyright of this image belongs to Icelandic Met Office.


The ML2.7 earthquake seen from Sauðárkrókur geophone that I am going to run until December 2011. Sadly, no live gif image of it due to network issues. Please note that this geophone is in a noisy location. This picture is released under Creative Commons Licence. See licence web page for more details.


The ML2.7 seen on Hvammstangi geophone. Sadly, no live gif image of it due to network issues. This picture is released under Creative Commons Licence. See licence web page for more details.

I do not know if there are going to be more earthquakes in this area. But it seems that this earthquake has happened in a area with known faults from post-glacial times (they are on my geological map of Iceland). So for now all that can be done is to wait and see what happens next this this area. But I am not expecting anything special in terms of more earthquake activity. There are no active volcanoes in this area.

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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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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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More on the Almannagjá fissure depth increase (Thingvellir)

The evening news on Rúv did show video of the fissure in Thingvellir. The fissure it self appears to be a extension of the current fissure named Almannagjá. That fissure is old. But this formation appears to be fresh. But it hard to know for sure how long it is since it was created. But the road has been there since the late 19th century. One of the ideas why this happened is that there is a connection with this fissure creation and the earthquakes in the SISZ in the year 2000 and 2008. But that however is unproven idea at this point.

Other then this I have not seen or got a lot of information about this fissure.

Here is a video of this fissure in the Rúv news at 19:00 UTC.

More information on Thingvellir and it’s geology.

Geology and tectonics of Þingvellir