Magma – Page 63 – Iceland geology

July 1, 2015July 1, 2015

Earthquake swarm continues on Reykjanes ridge, small chance of eruption

Today (01-July-2015) earthquake activity continued on the Reykjanes ridge, largest earthquakes so far are magnitude 5,0 (EMSC information here). Second largest earthquake had magnitude 4,8, other earthquakes have been smaller in magnitude. Total of 35 earthquakes that have taken place are larger than magnitude 3,0 and total number of earthquakes when this is written is 537.

Earthquake activity on the Reykjanes ridge. Green stars are earthquakes that are magnitude 3,0 or stronger. Copyright of this image belongs to Iceland Meteorological Office.

Earthquake activity has dropped but is ongoing at the moment. Copyright of this image belongs to Iceland Meteorological Office.

Earthquake activity now happens in pulses, with low activity for 2 – 4 hours before it increases again. It is not clear why this is taking place. Overall earthquake activity is dropping at the moment, it might increase again without a warning.

Yellow alert for risk of eruption

The alert level for this volcano that is now making earthquake noise has been raised to yellow. The change happened during my working hours so I was unable to write about it right away. This means there is a risk of eruption at this location, last eruption in this location was in the year 1879 according to the information I have collected here.

Current warning for the volcano at Eldey is yellow. Copyright of this image belongs to Iceland Meteorological Office.

I don’t know for sure at the moment what the chances are of an eruption at the moment. That should be clearer in next 24 – 48 hours (I hope).

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Article updated at 23:50 UTC.

June 29, 2015June 30, 2015

Deep earthquakes in Bárðarbunga and Tungnafellsjökull volcanoes

Even if the eruption in Holuhraun and Bárðarbunga volcano is over, there is no shortage of activity in Bárðarbunga volcano. With deepest earthquake in past 48 hours having the depth of 28,6 km and earthquakes don’t get a lot deeper than this in Bárðarbunga volcano. At this depth earthquake activity happens due to magma movements rather than tectonic stresses.

Earthquake activity in Bárðarbunga volcano (red dots). Copyright of this image belongs to Iceland Meteorological Office.

Earthquake activity in Tungnafellsjökull volcano

Since the end of the eruption and any major activity in Bárðarbunga volcano. Earthquake activity in Tungafellsjökull volcano has not stopped as expected. The earthquake activity continues at low levels and at great depth. With deepest earthquake in last 48 hours at 26,2 km.

Earthquake activity in Tungnafellsjökull volcano (yellow / orange dots). Copyright of this image belongs to Iceland Meteorological Office.

It is unclear what is going on in Tungnafellsjökull volcano, it is clear that dyke intrusion is taking place at depth, if and when that might result in a eruption is not clear at this moment. This might lead to an eruption or it might not. It is impossible to know at this moment since Tungnafellsjökull volcano has no recorded or documented history of volcano eruptions in historical times.

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June 10, 2015

Earthquake activity in Bárðarbunga volcano

Today (10-June-2015) an magnitude 3,3 earthquake took place in Bárðarbunga volcano. This earthquake had the depth of 6,3 km.

Magnitude 3,3 earthquake in Bárðarbunga volcano is shown with the green star. Copyright of this image belongs to Icelandic Meteorological Office.

No other earthquake activity has followed the magnitude 3,3 earthquake so far. This earthquake was a long period earthquake, that means it was magnetic in nature and was created by magma at 6,3 km depth. At the moment it is impossible to know for sure what is going to happen in Bárðarbunga volcano, far as I know there hasn’t been any inflation of Bárðarbunga volcano since the eruption in Holuhraun ended, that might have happened, just not detected due to the size of the area.

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June 7, 2015June 7, 2015

Overview of activity in Iceland in week 23

During Week 23 there hasn’t been a lot of activity taking place. Normal minor-earthquake activity has been taking place all over Iceland, some glacier earthquakes have been seen in Vatnajökull glacier. This spread out earthquake activity is normal for Iceland, it is also easily detected in Iceland due to the dense seismometer network in Iceland. Earthquake activity continues in Bárðarbunga volcano.

Normal earthquake activity in Iceland at the moment. Copyright of this image belongs to Icelandic Meteorologist Office.

At the moment the earthquake activity in Iceland is within normal background levels. Minor earthquake activity is almost always taking place in Iceland, there are few days when no earthquakes happen, but those days are rare and it is long between them. At the moment there is nothing to report in terms of the activity in Iceland.

Work schedule

This summer I am working Monday to Friday from 08:00 to 16:00. This means if anything happens I won’t me aware of it until I get back from work.

Donations

Please remember to support my work with donations. They help me work on this website and keep my alive. I have found out that food is expensive in Iceland and over the past two years that price has only gone up and it continues to do so. This means the budget I used in Denmark for food is not enough in Iceland (I have adjusted the plans, that type of living is going to be a challenge for the next 9 – 11 months when I am going to be living in Hvammstangi, Iceland). I am now close to getting completely broke. Most of my working income is going to pay up my debt (what I get of it, since I pay full tax [37,30%] of it in Iceland). I hope to be finished paying up all my debt in October. Thanks for the support.

Article updated at 20:48 UTC.
Article updated at 23:04 UTC.

May 20, 2015May 20, 2015

New swarm of deep earthquakes in Katla volcano

This morning (20-May-2015) a swarm of deep earthquakes took place in Katla volcano. This earthquake activity was at depth and it means that magma was moving or dyke intrusion taking place at depth.

Earthquake activity in Katla volcano this morning. The earthquake swarm took place close to 1918 eruption site. Copyright of this image belongs to Icelandic Met Office.

Deepest earthquake in this swarm had the depth of 28,9 km. Shallowest depth was 17,3 km. At this depth there is only magma that can create earthquakes, since crust at this depth in Iceland almost never has earthquakes (it might happen, but is rare event) that is not related to magma movements. This activity is something that needs to be monitored since it might suggest that conditions inside Katla volcano might be changing. There is no way to confirm at this point that to be the case. At the moment there is nothing to suggest that eruption is imminent in Katla volcano at this point. This deep earthquake activity appears to be over for now.

May 12, 2015May 13, 2015

How Bárðarbunga volcano collapsed

There is a good article about how Bárðarbunga volcano collapsed during it’s six month long eruption in Holuhraun. The most recent data (the work on Bárðarbunga volcano is far from over even there is no eruption taking place currently) show that Bárðarbunga volcano did in fact collapse. This collapse was not marked by a big explosion, but rather slow subsidence of Bárðarbunga volcano over a large area. Holuhraun eruption is the largest eruption in Iceland for the past 230 years, both in magma and size of the eruption.

More details can be found here.

Iceland’s Bárðarbunga-Holuhraun: a remarkable volcanic eruption (blogs.egu.eu)

May 2, 2015

New dyke intrusion in Katla volcano

Yesterday (01-May-2015) a minor dyke intrusion took place in Katla volcano. This dyke had depth down to 26,9 km and up to 18,5 km. This is the second dyke intrusion in this are in short space of time. Largest earthquake in the following earthquake swarm had the magnitude of 2,0.

Dyke intrusion in Katla volcano (dense cluster of earthquakes). Copyright of this image belongs to Icelandic Met Office.

While this doesn’t signal imminent eruption in Katla volcano this activity does have me concerned due to past experience with activity in Katla volcano. This might die out, but there is no way to know for sure. All that can be done is to wait and see what happens next in Katla volcano.

Notice on Grímsfjall volcano

There has been a slight increase in earthquakes in Grímsfjall volcano. This suggest that the volcano is about to be ready for its next eruption. Earlier eruptions took place 2011, 2004, 1998 … etc. It is impossible to know when or how big next eruption in Grímsfjall volcano is going to be.

April 30, 2015

Dyke intrusion in Bárðarbunga volcano

Today (30-April-2015) a minor dyke intrusion took place in Bárðarbunga volcano. This dyke intrusion was small and appears to be over for now. This does show that current activity in Bárðarbunga volcano is not over even if the eruption in Holuhraun has ended.

The dyke intrusion in Bárðarbunga volcano is a small cluster of earthquakes, it can be found on this image as three orange dots and one red dot. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake that appeared in the following earthquake swarm took place had the magnitude of 2,1. Depth of this earthquake swarm was around 17 km and going up to 5,3 km. Nothing suggest that at current time this dyke has reached the surface and no harmonic tremor was detected during the time this dyke intrusion took place in Bárðarbunga volcano. More dyke related activity should be expected in Bárðarbunga volcano in next few months to years. Other earthquakes in Bárðarbunga volcano are due to stress changes in the crust due to deflation the volcano came under during the eruption in Holuhraun, total subsidence of Bárðarbunga volcano during that eruption has been measured 62 meters. Current rifting activity is not over in this area even if no eruptions are taking place at the moment.

April 24, 2015April 24, 2015

Deep earthquakes in Katla volcano

Yesterday (23-April-2015) there where deep earthquakes in Katla volcano. So far only six deep earthquakes have been recorded. The deepest earthquake had the depth of 26,6 km. The largest earthquakes in this swarm had the magnitude of 2,2.

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

Earthquake activity at this depth is rarely due to tectonic activity, it is mostly due to magma movements or pressure changes of the magma. It is impossible to know for sure what is going on. No harmonic tremor was detected following this earthquake activity and there is nothing suggesting anything else then just earthquake activity in Katla volcano at the moment.

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Article updated at 16:21 UTC.

March 28, 2015

Deep earthquake activity in Bárðarbunga and Öræfajökull volcano

Today (28-March-2015) there has been deep earthquake activity in Bárðarbunga volcano. This suggest that there is a fresh injection of magma into Bárðarbunga volcano system. If this is going to result in new eruption remains to be seen. It is not impossible at current time to happen. So far however nothing has happened. Deepest earthquake had depth of 21,1 km, others earthquakes are shallower.

Earthquake activity in Vatnajökull glacier today. Copyright of this image belongs to Icelandic Met Office.

Öræfajökull volcano

Today (28-March-2015) there has also been deep earthquake activity in Öræfajökull volcano [Wikipedia link here]. This activity is not new and has been taking place every few months for the past 10 years or so. Quiet times are different in length. Each earthquake swarm that takes place is different in both magnitude and length, current activity appears to be deep, but mostly small earthquakes, less then magnitude 1,5 for most part. Deepest earthquake in this swarm had the depth of 25,0 km. This earthquake activity is only due to fresh magma entering Öræfajökull volcano system, not tectonic activity in this area due the depth of the earthquakes are taking place.

Based on historical accounts of earlier eruptions (1362 and 1728). It appears that eruptions in Öræfajökull start with powerful earthquake swarm (magnitude 4,0+ earthquakes). The following eruption is an ash cloud one with glacier floods taking place, with that phase lasting up to 48 hours. What happens after that is unclear, since it was not documented properly by historical records (at least not properly mentioned or lost due the old age of the historical records in question). Eruptions can last for up to 45 days, based on earlier documented eruptions. Current earthquake swarm is inside Öræfajökull volcano, since it is not round volcano, but goes a little to north where the earthquake swarm is taking place. There is no fissure swarm connected with Öræfajökull volcano, it does not rule out that one exist, it is at least not known at the moment. At the moment there are no clear sign that there is increased eruption risk from Öræfajökull volcano. That might change without warning, as is always the risk with volcanoes.

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