Dyke intrusions – Page 27 – Iceland geology

January 20, 2016January 21, 2016

Earthquake swarm in Bárðarbunga volcano (Week 03/2016)

Today (20-January-2016) at 13:05 UTC an earthquake swarm started in Bárðarbunga volcano. This earthquake swarm was not a surprise to me, since I had seen clues it would happen on 17 and 18 of January-2016 (more details later in this article). I wasn’t sure if it would happen.

The earthquake swarm in Bárðarbunga volcano today. Copyright of this image belongs to Iceland Met Office.

The largest earthquake in this swarm had the magnitude of 3,6 and that is a increase in magnitude from last earthquake swarm taking place at this location two weeks ago. This earthquake appears to have been created by a magma breaking rock under pressure (low frequency element present in it).

The harmonic tremor plot from Vonarskarð SIL station, next to Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

I have noticed and I told Icelandic Met Office about this few days ago. There is a change in the harmonic tremor plot at 2-4Hz few days before an earthquake swarm starts in Bárðarbunga volcano. This has happened several times. Last time this happened is on 17 and 18 January-2016. Why this happens I don’t know for sure. One idea is that magma is over-pressuring once it enters the magma chamber and this might be gas release in the magma at the same time. If that is the reality, it is creating a magma foam at the top of the magma chamber that would erupt rather explosively when the pressure breaks the magma chamber currently holding it (see here, I’m not sure what this is called in science). This is only a idea that I have, but I find it the most likely explanation on what is going on in Bárðarbunga volcano. This might be wrong, but only time is going to tell what happens in Bárðarbunga volcano.

The time period between earthquake swarms is getting slightly shorter, now it’s around half a week from a whole week as was last month (December-2015). This change of phase suggests that more magma is flowing into the magma chamber and possibly in greater volume. The path the magma flows into the magma chamber is clear of all blockage, that means no earthquakes are created at that location. Current evidence suggest that only one magma chamber is being filled up with magma at the moment, but that magma chamber might be big and with some room left, but that might be quickly running out as is suggested by current earthquake swarms. The earthquake activity would be considerably higher if an eruption was about to start.

If anything more happens in Bárðarbunga volcano this week I’m going to update this article. Unless an eruption starts, then I’ll write a new one.

Update 1

A minor dyke intrusion took place in Bárðarbunga volcano caldera today (21-January-2016). The strongest earthquake in this dyke intrusion had the magnitude of 2,8 and depth of 2,5 km. This was a small and short event that took place.

The dyke intrusion in Bárðarbunga volcano took place in SW part of the caldera. Copyright of this image belongs to Iceland Met Office.

It’s difficult to know for sure what this means. What is clear is that magma is trying to break a path to the surface and it might have found a weak spot in the crust inside the caldera. If this starts to be a regular feature it means problems. This is the second weak spot to form in the caldera, the first one being in North-east part of the caldera, creating weekly earthquakes since September-2015.

Article updated at 01:52 UTC on 21-January-2016. Error fixed in date (it was not 10 and 11, it was 17 and 18th of January-2016).
Article updated at 20:56 UTC on 21-January-2016.

January 10, 2016January 11, 2016

Bárðarbunga volcano earthquake swarm (Week 01 2016)

Current earthquake activity in Bárðarbunga volcano is going to be a regular feature until next eruption. Due to that I won’t write about all the earthquakes that happens, just when a magnitude 3,0 or larger earthquakes take place. The situation in Bárðarbunga volcano and nearby areas is getting more complex due to increasing magma activity at depth and surprising high number of them are creating pathways to the shallow crust. Since the eruption in Holuhraun ended there has been increase in earthquake activity in Bárðarbunga volcano, this is best seen by almost weekly magnitude 3,0 or stronger earthquakes. What has also been appearing over the past few weeks is deep activity in Trölladyngja, activity that started on 28 km depth and up to 20 km depth currently. That process only took around 1,5 – 2,5 months to happen (short amount of time). The activity in Trölladyngja is troubling in my view, since it’s my opinion that if the magma manages to create a pathway to the surface it is going to start an eruption in that area. Magma below Trölladyngja might also stop in it’s track, if it gets close enough to the surface without eruption it might create a new hill or new hydrothermal area while it’s cooling down. Whatever happens in the end is going to be interesting.

Latest earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

The second issue that is now starting to show it self is Loki-Fögrufjöll volcano, also known as Hamarinn. Today a magnitude 3,2 earthquake took place in it, not far from Skaftárkötlum cauldrons, the depth was 0,7 km. The earthquake today in Bárðarbunga volcano also had the magnitude of 3,2 with the depth of 0,1 km. Loki-Fögrufjöll volcano is a complex volcano with shallow magma chambers. After the last glacier flood it was clear that hydrothermal activity in Skaftárkatlar cauldrons is increasing the hydrothermal areas are growing in size. This means there is more energy flowing into the hydrothermal systems and the only way that happens if new hotter magma into the volcano. This development is troubling, both in short term and long term. This increases the risk of minor eruption in Loki-Fögrufjöll volcano considerable in my view. Risk of larger eruption in Loki-Fögrufjöll volcano has also gone up. Last eruption in Loki-Fögrufjöll volcano that was large took place in the year 1910 and lasted from June to October that year. Last minor eruption in my view took place in July 2011, lasting for few hours. That eruption has not been confirmed by geologists yet, I don’t know why that is. A glacier flood followed that eruption.

Other complexities in all of this are random fissures that might open up under unknown dykes, starting a eruption in areas that might not have seen a eruption in a long time. Along with new magma dykes going somewhere new. Whatever happens it is going to be interesting and this is going to take a long time. It takes Bárðarbunga volcano, since it starts it eruption cycle up to 20 years to finish once it’s started. The eruption cycle that started in 1862 did not end until 1910. A new eruption cycle started in 2014 and it’s ongoing. The longest eruption cycle I see in GVP data is a eruption cycle that started in 1697, it didn’t end until the year 1797.

Hekla volcano

A single earthquake with the magnitude of 1,7 took place in Hekla volcano today. Nothing else happened following this earthquake. This means Hekla volcano remains quiet.

Frost quakes

It’s cold now in Iceland. This means frost quakes have been appearing on Iceland Met Office SIL stations. This has also been increasing the noise levels on some SIL stations (the blue band when seeing harmonic tremor levels).

History of eruptions in Iceland

I’ve added a short link to a post that a made back in 2011 and I continue to update. This post has all of the eruptions in Iceland since the year ~900. This is good for people that want to check for historical eruptions in Iceland.

Article updated at 00:25 UTC on 11-January-2016. Updated for slight increase in clarity of wording.

December 26, 2015December 27, 2015

Fresh earthquake activity in Bárðarbunga volcano

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Last night (26-December-2015) two magnitude 3,3 earthquakes took place in Bárðarbunga volcano. This earthquake activity was followed by a change in activity on 2 – 4Hz band, I’m not sure why that is, it might signal a inflow of magma at depth into shallow parts of the crust. This is however only guess on my part, this change in signal and it’s origin.

The change in the SIL station can be seen between 25 and 26-December-2015 on the blue line. Copyright of this image belongs to Iceland Met Office.

It is my view that the risk of eruption in Bárðarbunga volcano is increasing fast and Bárðarbunga volcano might erupt without warning at any time. Iceland Met Office holds a different view and that is there is no major risk of eruption in Bárðarbunga volcano at the moment, even if magma continues to flow into Bárðarbunga volcano.

The earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

The magnitude 3,3 earthquake in north-east part of Bárðarbunga volcano caldera had the depth of 0,1 km. The magnitude 3,3 earthquake in south-east part of the caldera had the depth of 2,5 km. At 08:20 UTC this morning a magnitude 1,0 took place in Bárðarbunga volcano, that earthquake had the dept of 20,3 km and that suggest the magma inflow might be more than current ideas and models suggest (this earthquake is on the edge of the volcano, not far from Tungnafellsjökull volcano). I don’t know what is going to happen next in Bárðarbunga volcano. Since nobody knows for sure what is going to happen next in Bárðarbunga volcano.

Update 1

The earthquake activity in Bárðarbunga volcano has now created a half-circle of earthquakes in the caldera. Over the past 24 hours there has been slight increase in activity in Bárðarbunga volcano after the magnitude 3,3 earthquakes. There has also been some odd harmonic tremor spikes around Bárðarbunga volcano, the problem is that at the moment there is bad weather taking place at this location in Vatnajökull glacier area. So this might just be wind. I have to wait until the weather gets better in order to see if anything changes.

The earthquake activity in Bárðarbunga volcano at 27-December-2015. Copyright of this image belongs to Iceland Met Office.

I don’t know if any more activity is going to take place. This might die down, it is difficult to be sure about what happens next.

Article updated on 27-December-2015 at 17:56 UTC.

December 20, 2015December 20, 2015

Earthquake activity in Bárðarbunga volcano

Last night (20-December-2015) a earthquake activity took place in Bárðarbunga volcano. Largest earthquake in this short earthquake swarm had the magnitude of 3,5 and the second largest earthquake had the magnitude of 3,1. This earthquake activity is shallow and above above 10 km depth and it appears to be result of magma activity in north-eastern part of Bárðarbunga volcano caldera. The earthquakes that took place appear to be long period volcano earthquakes (details can be found here, under b-type earthquake).

Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

There clearly is something going on in Bárðarbunga volcano, it is already known that inflation is taking place in Bárðarbunga volcano after the eruption in Holuhraun ended in February-2015. Along with increase in dyke intrusions this clearly suggest that magma pressure is increasing inside Bárðarbunga volcano. What worries me is not the risk of large eruption in Bárðarbunga volcano. The risk in my view is at the moment risk of small eruption taking place, if a small eruption takes place under a glacier it is going to mean glacier flood. Size depends on the eruption size, duration and other factors. Currently there are no signs of imminent eruption, but that might change without warning. The north-eastern part of the Bárðarbunga volcano caldera is in my view weakened structure due to all the earthquake activity for the past 15 (about) months.

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December 16, 2015

Minor dyke intrusion in Bárðarbunga volcano

From 20:10 to 20:14 UTC a minor dyke intrusion took place in Bárðarbunga volcano. This dyke intrusion was small, only lasting those few moments and the largest earthquake had the magnitude of 2,5. Other earthquakes are smaller. Depth was from 15,6 km to 23,2 km. Based on the location, this is clearly a dyke intrusion into Bárðarbunga volcano. It is too small to start an eruption, but suggest that magma processes in Bárðarbunga volcano are starting to increase again.

The dyke intrusion in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

There is also a change in the SIL station Vonarskarð. What is creating remains unknown. This might be a change in hydrothermal systems under the glacier, but is impossible to know for sure at this point in time. Copyright of this image belongs to Iceland Met Office.

I don’t know if any more earthquake activity is going to take place in Bárðarbunga volcano. Since it is impossible to know what magma does next inside a volcano. At the moment I’m not expecting a eruption in Bárðarbunga volcano.

November 28, 2015November 28, 2015

Deep earthquakes in Katla volcano – renewed activity

Yesterday (27-November-2015) new earthquake activity took place in Katla volcano. This activity, in part of the Katla volcano caldera is a repeated pattern, this means that this has happened before. Last activity of this type took place in September (from what I remember). This activity suggests that a magma is building up at the east part of the caldera at the depth of 20 – 28 km (in my view). Currently there is no risk of eruption.

Earthquake activity in Katla volcano on 27-November-2015. Copyright of this image belongs to Iceland Met Office.

It is difficult to know if there is going to be more activity in Katla volcano. It might happen and it might not. All that can be done is to wait and see.

Changes in Amazon advertisements

Due to agreement changes regarding Amazon advertisement (or associates it’s called in some markets) I have to close down my accounts for Italy and Spain right now. That is due to the fact that I don’t have any income from those accounts. I’ve had little income (one sale) on Amazon France, but if it’s usage does not increase soon I’m also going to close it down soon. The reason for this is that Amazon now takes a “maintenance fee” from accounts that don’t have any income. This is new and I’m not going to support Amazon in this way if I can avoid it. So any Amazon account for advertisements that doesn’t provide income for a long period of time is going to get closed down (this are periods of at least 12 months).

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The move back to Denmark

I’m going to move back to Denmark in March of 2016 (maybe earlier) if everything has been shorted out. I’m not sure if that is going to happen, currently I’m dealing with a large issue with the Danish Tax and I can’t move to Denmark until that has been resolved.

Article updated at 02:18 UTC.

November 15, 2015November 15, 2015

Deep earthquakes close to Trölladyngja (Bárðarbunga volcano)

During the night of 15-November-2015 a swarm of deep earthquakes took place not far from Trölladyngja. The thing about Trölladyngja is directly connected to Bárðarbunga volcano and its eruption cycles. Trölladyngja it self was formed in a eruption in the year 5000 BCE, according to historical overview from Global Volcanism Program. According to some sources, Trölladyngja is a shield volcano, I don’t know if that is exactly correct. Regardless of what type of volcano Trölladyngja is, there is clearly something going on in it. Since this is not the first time I see earthquake swarm at this depth at this location. I doubt that this are stress related changes in the crust due the collapse of Bárðarbunga volcano caldera.

The earthquake activity in Trölladyngja (red dot). Image is from 05:50 UTC. Copyright of this image belongs to Iceland Met Office.

All of the earthquakes taking place were small, the largest had the magnitude of 1,1 and the depth was from 18 – 15 km.

In the early days of the earthquake swarm that started in Bárðarbunga in August-2014 a dyke intrusion pushed into this direction and than it just stopped as it lost the energy, or hit a obstacle that it was unable to break trough.

Image from August-2014. The earthquake activity close to Trölladyngja is clear on this image. Copyright of this image belongs to Iceland Met Office.

I don’t know yet what the chances are for an eruption at this location. More earthquake swarm activity is needed until the magma that is clearly down there breaks up. However the rifting that is taking place in this location might speed things up by unknown factor. This rifting might and possibly is allowing more magma entering this area deep underground without any earthquake activity. It is difficult to know what is going on at this location, so a lot of this is a speculation on what might happen. What actually happens in the end is a whole different thing and only time is going to tell us what happens next.

November 4, 2015November 4, 2015

Earthquake swarm in Bárðarbunga volcano

Today (4-November-2015) a earthquake swarm took place in Bárðarbunga volcano. This is now almost a weekly feature in the Bárðarbunga volcano system. This is suggesting that magma pressure inside Bárðarbunga volcano is currently increasing at rather fast phase. If and when this might start a new eruption is impossible to know. Largest earthquake in this swarm had the magnitude of 3,1.

Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

I’m expecting this earthquake activity to continue for some time now. At least until a new eruption occurs in Bárðarbunga volcano, since the rifting process that started all this has not ended and this is going to last few more years.

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Article updated at 23:14 UTC.

September 24, 2015

Increased activity in Tungnafellsjökull volcano

This is going to be short update on the activity in Tungnafellsjökull volcano. I just don’t have the time to write long article about it, doing so takes up to two hours to write. A time that I just don’t have at the moment due to work (and school) tomorrow.

Today (23-September-2015) there has been a sharp increase in earthquake activity in Tungnafellsjökull volcano. Largest earthquake so far had the magnitude of 3,0. Other earthquakes have been smaller in magnitude. Most of the earthquakes that have been taking place are shallow, but all of them (at least that appear on my geophones) are appearing to be long-period earthquakes. Suggesting that magma created them, rather than tectonic forces in the crust.

The earthquakes in Tungnafellsjökull volcano. Copyright of this image belongs to Iceland Met Office.

It is the official view of the Iceland Met Office that this activity is due to tectonic stresses in the volcano, due to adjustment of Bárðarbunga volcano. This is true, that is not the whole story in my view. Some of the earthquakes taking place in Tungnafellsjökull volcano are due to tectonic adjustment of the crust (stress changes). What adds complexity to this image is the fact that magma is involved in Tungnafellsjökull volcano, the problem that since there are no documented eruptions from Tungnafellsjökull volcano, it’s impossible to know for sure what happens before an eruption in it. If the current influx of magma results in an eruption is difficult to say for sure, at the moment I don’t rule it out. It is my view that there is now more chance, rather than less of an eruption in Tungnafellsjökull volcano.

September 12, 2015September 12, 2015

Something is going on in Hamarinn (Bárðarbunga) and Tungnafellsjökull volcanoes

Today (11-September-2015) an earthquake swarm started in Hamarinn volcano (no GVP profile, see Bárðarbunga volcano). This is a volcano that is inside Bárðarbunga volcano fissure swarm and might be connected to it, that connection is unclear, but historical data suggests that once Bárðarbunga volcano gets erupting sometimes Hamarinn volcano does too. There is a similar pattern in Grímsfjall volcano and Þórðarhyrna volcano (no GVP profile) as an another example.

Current sequence of earthquakes in Hamarinn volcano started with a small earthquake at 22,5 km depth. Few shallower earthquakes happened before that event, those earthquakes however might be connected to changes in hydrothermal systems in the volcano, rather then something else. The deep earthquake that took place started a series of smaller earthquakes at shallower depth, suggesting that pressure is already high inside the volcano, how close it might be to erupting is impossible to know, but the clues that I’m not seeing do not look good. This might die out, but I think the chance of that are small. Last eruption in Hamarinn volcano took place in July-2011, I wrote about it here, here and here.

Current area of activity in Hamarinn volcano. This area is covered with a thick glacier up to 300 – 400 meters. Copyright of this image belongs to Iceland Met Office.

Harmonic tremor data is showing that current earthquake activity are low and long period earthquakes (green and red spikes). I also noted that on this image a harmonic tremor spike can be seen on the green band. It does not appear visible on the red and blue bands. I’m unclear on why this is. Copyright of this image belongs to Iceland Met Office.

The harmonic tremor spike does not appear on the SIL station Skrokkalda. I don’t know why that is. Earthquake activity appears clearly on it (spikes). Copyright of this image belongs to Iceland Met Office.

Activity in Tungafellsjökull volcano

There has been interesting earthquake activity in Tungafellsjökull volcano today. Today earthquake swarm started with the depth of 12,3 km and it mostly stayed there. Suggesting that magma dyke injections are taking place in the volcano at the moment. If and when this might lead to an eruption is impossible to know. Magma might be at shallower depth already due to high activity during the eruption in Bárðarbunga volcano.

The earthquake activity in Tungafellsjökull volcano, it’s located north of both Bárðarbunga and Hamarinn volcano (NE of Hamarinn). Current activity is a small cluster of earthquakes in north-east part of Tungafellsjökull volcano. Copyright of this image belongs to Iceland Met Office.

Largest earthquake in this swarm so far had the magnitude of 1,9. It was also the shallowest earthquake in this swarm. So far no change on the surface of Tungnafellsjökull volcano, meaning that no hydrothermal vents have appeared so far. That might not happen since formation of hydrothermal vents does not always happen before an eruption.

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