Category: Magma

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Minor earthquake activity in Öræfajökull volcano

Over the past few weeks there has been a slight increase in earthquakes in Öræfajökull volcano. Due to glacier quake activity I’m only using earthquakes that have confirmed depth of 1,5 km or deeper. This earthquake activity is minor and doesn’t suggest that an eruption is imminent, it however does suggest that something is going on.

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Öræfajökull volcano is to the south on this image (two red dots). Copyright of this image belongs to Icelandic Met Office.

This activity has a long history, it started happening in 2012 at the earliest that I know of and has been going on slowly since then. Öræfajökull volcano did go from having no earthquakes and up to having two to five earthquakes a year. Sometimes more. There are clues in this activity that magma might be starting to push it self up into the volcano, but at the moment it doesn’t seems to be going far up into the volcano. Based on the current depth and low seismicity in Öræfajökull volcano. I don’t expect this to change any time soon. Since most of the time, at least for the moment there is little to no earthquake activity taking place in Öræfajökull volcano.

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Earthquake activity in Bárðarbunga and Grímsfjall volcanoes

Yesterday (17-March-2016) an earthquake swarm took place in Bárðarbunga volcano. This is a weekly cycle at the moment in Bárðarbunga volcano so older readers are used to seeing and read about it already. This started in September 2015 (for the new readers) after the eruption in Holuhraun ended in February 2015. This activity suggest that magma has started to flow into the magma chamber in Bárðarbunga volcano again at faster speeds than before the eruption in Holuhraun. The exact rate is difficult to know, since the magma that started the eruption in Holhraun had been building up in Bárðarbunga volcano since 1970-ish and part of that time earthquake recording was poor or did not exist in Iceland or parts of it until 1995 when the SIL network was created by Veðurstofa Íslands.

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The earthquake activity in Bárðarbunga and Grímsfjall volcanoes. Copyright of this image belongs to Iceland Met Office.

The largest earthquake this week had the magnitude of 3,4 while other earthquakes that took place had smaller magnitude. The second largest earthquake had the magnitude of 2,8. Other earthquakes where smaller in magnitude. It is also interesting that part of the earthquake swarm aligned it self along north-south fault in the eastern part of the caldera. That is a new feature, either a weakness is forming at this location or something else is up. This area has around 300 – 500 meter thick glacier on top of it and an eruption at this location would be extremely bad. The glacier flood from eruption at this location would mostly go down Jökulsá á fjöllum glacier river. Other flood locations can’t be ruled out (I’m not an expert on glacier floods and I do have limited knowledge of the landscape under the glacier).

Grímsfjall volcano

It has been five years since Grímsfjall volcano erupted in a largest eruption in 140 years for Grímsfjall volcano. Over the past few weeks there has been a slight increase in earthquake in Grímsfjall volcano. At the moment this doesn’t mean an eruption is imminent, the thing however about eruptions in Grímsfjall volcano is that they happen suddenly and without warning. Normally eruption happens in Grímsfjall volcano every 3 – 5 years on average, sometimes its shorter and sometimes its longer between eruptions.

Notice on Böðvarshólar geophone station

For the longest time now I’ve been having 3G connection issues with Böðvarshólar geophone station. The problems include poor signal, little bandwidth. The poor signal leaks into my recording of earthquakes, making them bad and extremely noisy and that makes them less usable for me. I am going to attempt to improve this situation but if that fails I will have to turn the station down. Since the cost of getting a good antenna for this location is too high and the solution takes too long to implement anyway. I will post a notice if I take down the Böðvarshólar geophone station. If it happens, it is going to happen before I move to Denmark.

Article updated on 18-March-2016 at 13:31 UTC. Minor spelling error fixes.

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Deep earthquakes in Askja volcano (15-March-2016)

Yesterday (15-March-2016) an earthquake swarm took place in Askja volcano. This was an deep earthquake swarm, with deepest earthquake having the depth of 18,7 km and the shallowest earthquake with the depth of 14,9 km. The earthquake swarm took place inside the volcano and there are clues that suggest it has it’s origin. This has been happening regularly since 2010 and after the Bárðarbunga volcano dyke getting close to the main magma chamber in Askja volcano the activity has slowly been increasing. This activity is not above background levels and nothing suggests that an eruption is about to happen any time soon.

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Askja volcano is located to the north-east of Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

For the moment the progress and the change in Askja volcano is slow, but that might change if the magma inside the system finds a pathway to the surface. If an eruption does happen I’m not expecting anything big, just a lava eruption that is going to go on for few days to weeks. Unless the magma gets into contact with water, creating a short term explosions. This is only a speculation, but Askja volcano is an active system and as such anything should be expected from it.

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Still mostly quiet in Iceland

Today (10-March-2016) an magnitude 3,2 earthquake took place in Bárðarbunga volcano. The location of the earthquake swarm was in the caldera, with the location of the 3,2 magnitude earthquake being in the North-east part of the caldera.

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

The depth of this earthquake swarm was shallowest at 0,1 km, but most depth was 8,6 km. No other change has been observed in Bárðarbunga volcano so far. Other than this minor activity today in Bárðarbunga volcano activity remains low in Iceland. Currently there are storms passing over Iceland, that reduces the sensitivity of the SIL network.

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Possible confirmation of minor eruption in Hamarinn volcano in July 2011

In July-2011 a minor eruption took place in Hamarinn volcano (part of Bárðarbunga volcano system). For a long time I’ve thought that those events in Hamarinn volcano where an eruption, rather than anything else. Due to how the glacier flood appeared and how sudden this all thing did happen.

Today (05-March-2016) Stöð 2 (Channel 2) ran a small news segment about this and the possible confirmation of this minor eruption in Hamarinn volcano in July-2011. I have the same view on the minor eruption in Katla volcano that same month. Its the view of Magnús Tumi, professor in geology that the events in Katla volcano where due to hydrothermal activity, not a minor eruption. I disagree with his assessment on what did happen in Katla volcano that summer. The top flood from Hamarinn volcano in July-2011 was 2.200m³/sec.

The articles I wrote about the events in Hamarinn volcano can be found here.
New harmonic tremor detected. But it is not from Katla volcano
Glacier flood confirmed from Vatnajökull glacier, flood is from Hamarinn volcano (Loki-Fögrufjöll area)

Vísir.is / Stöð 2 news in Icelandic

Lítið leynigos líklega í Vatnajökli árið 2011 (Vísir.is, Icelandic, images, video)

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Four minor eruptions took place in Bárðarbunga volcano in August-2014

In Stöð 2 (Channel 2) news this evening was a short news segment about four minor eruptions that took place in the time between the dyke intrusion starting (16-August-2014) in Bárðarbunga volcano and until the eruption in Holuhraun (second link here) started (29-August-2014). The second small Holuhraun eruption, that lasted only for few hours (link 1 here [images, 2014], second link here [images, 2014]).

Those eruptions where small, didn’t break the glacier surface, but they did create small cauldrons. Three of those eruptions took place above the dyke on its path to Holuhraun eruption site. One of the eruption took place in side of Bárðarbunga volcano, south of the caldera (red circles on the map in the news). The mystery of what happened to all the melt-water has been mostly solved. Following this eruptions a rift episode took place (ongoing) and that formed cracks in the surface, allowing the water to go underground and not flowing into the nearby glacier rivers.

Magnús Tumi, the geologist spoken with at Earth Science at University of Iceland doesn’t think Bárðarbunga volcano is preparing for a new eruption. I disagree with his assessment. I base my assessment on earlier documented history, far as that goes and also the fact that rifting is currently taking place in this area and such events never do things quietly, even if no eruption happens, earthquakes do (and a lot of them).

Vísir / Stöð 2 news segment in Icelandic

Fjögur önnur eldgos urðu í Vatnajökli frá Bárðarbungu (Visir.is, Icelandic, video, images)

Article updated at 00:50 UTC on 04-March-2016. Error fixes.
Article updated at 21:16 UTC on 05-March-2016. Error fixes.

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Earthquake swarm in Bárðarbunga volcano (Week 09)

Bárðarbunga volcano continues it earthquake activity and it has now been a year since the eruption in Bárðarbunga volcano ended in Holuhraun (article I wrote about it can be found here). This activity (image) took place on 2-March-2016.

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The earthquake activity in Bárðarbunga volcano. Green stars are earthquake with magnitude above 3,0. Copyright of this image belongs to Iceland Met Office.

Largest earthquakes in this swarm had the magnitude of 3,1, 3,3 and 3,6. Other earthquakes where smaller in magnitude. The reason for this earthquake swarm seems to be a developing weakness in the north and western part of the caldera. Activity in south part of the caldera seems to be crust adjustment to this weakness (stress changes). The weakest area is long one (I didn’t find information on how large the caldera is, but it is large). This weakness is going to continue to develop until an eruption happens or the magma finds it self a new path and that is more likely than an eruption taking place in the caldera rim, however I cannot rule out an eruption in the caldera at this point. This is all just wait and see situation at the moment. Interesting earthquake also took place in Hamarinn volcano, it had the depth of 13 km and magnitude of 0,7.

Deep earthquakes also took place in Tungnafellsjökull volcano. That earthquake had the magnitude of 0,8 but depth of 17,9 km. Suggesting that some stress changes at depth are taking place. In this case I doubt magma created the earthquake.

If an ash eruptions takes place in Bárðarbunga volcano, the resulting ash fall would be devastating (besides the following glacier flood). Last time larger eruption took place in 1477 half of Iceland got covered in volcano ash (that’s 50% of land), the volcano ash eruption in 1711 covered north Iceland and large parts of east Iceland. In 1711 to 1729 total of nine glacier floods took place and the source of them is believed to be Bárðarbunga volcano. Glacier floods from other volcanoes (Grímsfjall, Kverkfjöll, Þórðarhyrna, Hamarinn) are also highly dangerous. The volcano ash had thickness up to 100 meters next to the eruption area in 1477 (see map in link 1).

Source 1: Hvaða tjón gæti mögulega hlotist af gosi í Bárðarbungu? (Icelandic)
Source 2: Hvað eru mörg gos þekkt í Bárðarbungu og hefur orðið mikið tjón af þeim? (has gravity map of Vatnajökull glacier, Icelandic)

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Short overview of earthquake activity in Iceland

This is a short update of earthquake activity in Iceland on 28-February-2016.

Bárðarbunga volcano

Over the past 48 hours there has been earthquake activity and dyke activity in Bárðarbunga volcano. Some of this earthquake activity has been on around 15km depth. Suggesting magma movements within Bárðarbunga volcano system. Earthquake activity always seems to increase few hours to days after a swarm of deep earthquakes appear in Bárðarbunga volcano.

A dyke activity has appeared on the edge of Bárðarbunga volcano, it is located south-east in the volcano. In a area that has seen this type of dyke activity before. It is interesting that this activity seems to persist at this location.

Tungnafellsjökull volcano

Over the past few days few earthquakes have appeared in Tungnafellsjökull volcano. Some of those earthquakes have had the depth around 15 km. This suggest some type of magma movements inside the volcano, but nothing that suggests that its going to reach the surface any time soon.

Askja volcano

Earlier this week (Week 08) an deep earthquake swarm took place in Askja volcano. With earthquakes having the depth down to around 22 km. Suggesting that magma is flowing into Askja volcano magma chamber at depth. This has been happening at regular basis since 2010. At the moment there is nothing suggesting that eruption is going to happen any time soon in Askja volcano.

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Earthquake activity in Bárðarbunga, Tungnafellsjökull and Askja volcano. Copyright of this image belongs to Iceland Met Office.

Katla volcano

There was some minor earthquake activity in Goðabunga in Katla volcano. This appears to be normal activity for this region of Katla volcano. No other interesting activity took place this week (Week 08) in Katla volcano.

Hekla volcano

Two earthquake where detected in Hekla volcano. Nothing else happened following this earthquake activity. Why this earthquake activity happens remains unclear.

Torfajökull volcano

A minor earthquake activity took place in Torfajökull volcano during the weekend. This activity is possibly due to changes in hyrdrothermal areas in Torfajökull volcano.

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Earthquake activity in Katla, Torfajökull and Hekla volcano. Copyright of this image belongs to Iceland Met Office.

Other than this activity things remain quiet in Iceland. There are few minor earthquake swarms on Reykjanes peninsula and Tjörnes Fracture Zone. But they are too small at the moment to write about.

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Move to Denmark

It is now official. I’m moving back to Denmark on 14. April, with just few minor details left to work out (getting a loan for the apartment insurance and few other things). I’ll move into my new apartment on the 15th April. More details later next weeks when I know about the apartment loan.

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Deep earthquake activity in Bárðarbunga and Askja volcano

Today (18-February-2016) and yesterday (17-February-2016) there has been deep earthquake activity in Askja volcano and in Bárðarbunga volcano.

Askja volcano

Since March 2010 Askja volcano has been having period activity taking deep inside Askja volcano. This suggests that both deep dyke intrusions are taking place in the volcano system, yesterday and today (close to Dreka area and Herðubreiðartögl volcano). None of those dyke intrusions is going to reach the surface. They are going to remain at depth. This does show that since 2010 magma activity at depth is possibly increasing in Askja volcano. When a eruption might take place is impossible to know, but it might be a really long time until it happens. Unless Bárðarbunga volcano enters the mixture and speeds things up. Earthquake activity close to Herðurbreið are normal tectonic earthquakes at shallow depth >10km.

Bárðarbunga volcano

Most of this week Bárðarbunga volcano has been quiet. That might be about to change, since today few deep earthquake appeared in the northern part of the volcano. This suggests that fresh magma from deep magma chamber is pushing up now. The resulting earthquakes are due to pressure change inside the volcano that fractures the rock in the process. Earthquake activity has also been in the dyke (Holuhraun eruption) at the edge of the glacier. I don’t know why that is. A clear dyke intrusion took place in Hamarinn volcano on 17-February-2016, with earthquakes at the depth of 12 – 13 km. This is the first dyke activity in this volcano for a while now. Magma is shallow in Hamarinn volcano, making it sensitive to pressure changes and possible eruptions.

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Earthquake activity in Askja and Bárðarbunga volcanoes. Along with earthquake activity close to Herðurbreið area. Copyright of this image belongs to Iceland Met Office.

Maps of Iceland

For people who want to know what I’m often taking about there is a map that can be bought. This is a geological map of Iceland, it shows all the volcanoes, both active and extinct ones in Iceland. Along with fault zones and fissure swarms. It can be bought from here. Please note that I don’t get anything from this, it’s just so that people can have access to information about Iceland. The prise of this map is €13,80 without shipping, or 15,31 USD without shipping today.

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Earthquake swarm in Bárðarbunga volcano (Week 06/2016 #2)

On Saturday 13-February-2016 at 19:32 UTC an magnitude 3,6 earthquake took place in Bárðarbunga volcano. Depth of this earthquake is registered 1,1 km. Swarm of smaller earthquakes followed the main earthquake, deepest earthquakes had the depth around 12 km.

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

Tungafellsjökull volcano

On Sunday 14-February-2016 an earthquake swarm started in Tungafellsjökull volcano. It’s still not known what is creating the earthquake activity in Tungnafellsjökull volcano. The most popular idea (among geologists) is that stress changes from Bárðarbunga volcano is resulting in earthquake activity in Tungafellsjökull volcano. I don’t know if that is true or not, since earthquake activity in Tungafellsjökull volcano started several years before the eruption in Bárðarbunga volcano in August-2014.

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