Category: Monitoring

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Earthquake swarm in Tjörnes Fracture Zone

Today (25-September-2013) an earthquake swarm started in Tjörnes Fracture Zone. This earthquake swarm started slowly and was mostly making small earthquakes early on. The largest earthquake today had the magnitude of 2.8 according to automatic results from Icelandic Meteorological Office. Currently the earthquake swarm is ongoing.

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Earthquake swarm in Tjörnes Fracture Zone. Copyright of this image belongs to Icelandic Meteorological Office.

I am expecting this earthquake swarm to continue for the next hours at least. TFZ is highly active when it comes to earthquake activity so this earthquake swarm is no surprise. If any major earthquake take place in TFZ it’s possible to see them here on my webicorder website.

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Minor earthquake swarm in Öræfajökull volcano

An minor earthquake swarm took place in Öræfajökull volcano today (09-September-2013). This was just minor earthquake activity and it was at shallow depth, just around 2.6 to 4.8 km. Largest earthquake in this swarm had the magnitude of 2.0.

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Earthquake activity in Öræfajökull volcano. Öræfajökull volcano is located south-most part of Vatnajökull glacier (next to the km line on the map). Copyright of this image belongs to Icelandic Meteorological Office.

Earthquake activity is not common in Öræfajökull volcano and that makes this activity interesting. So far this is just earthquake activity and I am not expecting anything else to take place. More earthquakes might happen in next few days to weeks. Or nothing else might happen Öræfajökull volcano.

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Interesting earthquake activity in Hamarinn volcano

Over the past few days interesting earthquake activity has been taking place in Hamarinn volcano. The earthquakes have been aligning along two east-west lines. Possibly an fissure in the volcano. I am not sure why this is happening, but I did record one earthquake from Hamarinn volcano today (07-September-2013) and that trace suggests this earthquakes have there origin in magma movements in the Hamarinn volcano. That has not yet been confirmed and this might never be confirmed due to lack of data. Largest earthquake so far had the magnitude of 2.2 at the depth of 4.5 km.

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Hamarinn volcano earthquake activity. Copyright of this image belongs to Icelandic Meteorological Office.

Last eruption in Hamarinn volcano was on 11 – 12-July-2011. It was an minor eruption and I did cover it here and here. Small eruptions are common in Icelandic volcanoes just as the are in other volcanoes around the world. Before the minor eruption in the year 2011 there was several months of earthquake activity in Hamarinn volcano. The area that now has this earthquake activity is the same area that had this minor eruption in the year 2011. I do not know if current activity is an early indicator that it is going to happen again. It however cannot be ruled out currently. What can be done is to monitor current levels of activity and just wait and see what happens next.

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Minor earthquake swarm in Esjufjöll volcano

Today (05-September-2013) an minor earthquake swarm took place in Esjufjöll volcano. Largest earthquake in this swarm had the magnitude of 2.2 and the depth of 4.9 km.

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Earthquake swarm in Esjufjöll volcano. Esjufjöll volcano are located in south part of Vatnajökull glacier, just northeast of Öræfajökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquakes in this area are because of magma movement it is believed. Now there are more SIL stations in the area, so more earthquakes are being recorded. Few years ago the lowest magnitude that Icelandic Meteorological Office was able to detect in Esjufjöll volcano was magnitude 1.5 and above.

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Earthquake activity in several volcanoes

Today (04-September-2013) had some minor earthquake activity in several volcanoes in Vatnajökull glacier. All of this earthquakes were small and less than magnitude 3.0 in size.

Kverkfjöll volcano

The deepest earthquake activity was in Kverkfjöll, with earthquakes at 31 km depth and 24 km depth. This deep earthquake activity is possible connected to magma movements since tectonic earthquakes are unlikely to take place this deep in the crust.

Grímsfjall volcano

One earthquake was recorded in Grímsfjall volcano, it was minor and shallow. This might even just be a glacier quake, rather than normal earthquake.

Öræfajökull volcano

Öræfajökull volcano did see two earthquake today, at the depth of 4 to 5 km. Both were small and tectonic in nature from the looks of it. Earthquakes are not common in Öræfajökull volcano so I am not sure why this increase has now taken place. It is worth noticing that sil network is now more sensitive in this area than before since new stations have been added in this area. This means that smaller earthquakes are now being detected than before.

Esjufjöll volcano

Esjufjöll volcano had two earthquake, the third earthquake might be a ice-quake. I am not sure if it was an real earthquake or not. Esjufjöll volcano normally do not have any earthquake activity, but few years ago an earthquake activity started with earthquakes that had magnitude of 2.5 to 3.0 so there is something going on in this volcano. What that might be I am not sure of yet.

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Earthquake activity in Kverkfjöll, Öræfajökull, Esjufjöll, Grímsfjall volcanoes. All small earthquakes. Copyright of this image belongs to Icelandic Meteorological Office.

I do not expect anything major to take place in Vatnajökull volcano. Since the current quiet period in Iceland just seems to be ongoing as is.

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Minor earthquake in Hekla volcano

Today (04-September-2013) a minor earthquake took place in Hekla volcano. The magnitude of this earthquake was just 0.4 and the depth was 0.1 km, so this earthquake was not connected to magma movements of any type.

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The earthquake in Hekla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Based on how shallow this earthquake was, it is unlikely that it means anything in terms of possible eruption in the volcano. At the moment there are same chances for Hekla volcano eruption as any other day of the week, that has not changed at all.

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Minor earthquake swarm in Torfajökull volcano

Today (03-September-2013) a minor earthquake swarm took place in Torfajökull volcano. The largest earthquake had the magnitude of 1.1, no other larger earthquakes took place in Torfajökull volcano.

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Earthquakes in Torfajökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Smaller earthquake swarms are common in Torfajökull volcano. They do not mean that eruption is about to take place, however magma is shallow in Torfajökull volcano and it has not erupted since 15th century at least (I think, there is no use in GVP website at the moment).

Donations: It would be nice if people donated so that I can buy food this month. In other case I am going to have to eat really little this month and I am not happy about such things taking place.

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Minor dike intrusion into Bárðarbunga – Hamarinn volcanoes

It seems that yesterday (02-September-2013) a minor dike intrusion took place in Bárðarbunga – Hamarinn volcanoes. This created an minor harmonic tremor yesterday on nearby sil stations. There were earthquakes following this events, the strongest one had the magnitude of 2.8 at the depth of 14 km. A second earthquake with the magnitude of 2.1 took place few moments later, it had the depth of 15.5 km. Only one smaller earthquake have seen taken place in this area of Bárðarbunga – Hamarinn volcanoes.

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The earthquake activity in Báðarbunga – Hamarinn volcano area. Copyright of this image belongs to Icelandic Meteorological Office.

It is important to notice that dike intrusions are common in this area, often happen many times a year. How many takes place can vary between years. That dike intrusion took place does not mean an eruption is going to take place. It just means that magma moved, what that means for the future is unknown at present time.

Donations: It would be nice if people donated so that I can buy food this month. In other case I am going to have to eat really little this month and I am not happy about such things taking place.

Blog post updated at 21:43 UTC on 3-September-2013.

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Interesting harmonic signals appearing around Vatnajökull glacier

In the past few hours an interesting harmonic signals have been taking place on two sil stations (so far) around Vatnajökull glacier. I do not know what is creating this harmonic tremor spikes on them, it might be water on the move or starting to move from Skaftár cauldron in Vatnajökull glacier or it might be something different that I do not know about at present time. Currently the source of this harmonic tremor is unknown and it might never been known in the worst case. I do hope to figure out in next few hours what is creating this harmonic tremor spikes on this two sil stations.

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The harmonic tremor signal at Skrokkalda sil station. The harmonic tremor signal can be found at the end of the tremor plot. Copyright of this image belongs to Icelandic Meteorological Office.

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The harmonic tremor signal at Jökulsel sil station. It is at the end of the tremor plot. Copyright of this image belongs to Icelandic Meteorological Office.

As I say above, the source of this tremor signal is not known. It might be bad weather in the area, traffic (unlikely due to bad weather in this part of Iceland at the moment) or something that is not known at the moment. What I can rule out at the moment is this harmonic tremor signal does not appear to come from magma movement, the frequency of the harmonic tremor is too high for that at the moment and does not show little to no energy at 0.5 to 1 Hz band. This suggest the source is something else then magma, this however does not rule out magma. Since magma is known to due many strange things under pressure and high frequency harmonic tremors are not unknown, but they are unlikely to take place rather than being a common feature in volcano activity.

For the moment the best thing that can be done is to monitor the signal and see if there are any changes and on the nearby sil stations. For the moment I do not expect any major change in this area, risk of glacier flood is still in place for this part of Vatnajökull glacier. If this harmonic tremor signal connects to that is not known at the moment.

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Possible glacier flood from Skaftár cauldron

It is possible that glacier flood from Skaftákötlum cauldron has started some hours ago. According to Rúv, Icelandic Meteorological Office is now monitoring for signs that glacier flood has started. Changes in conductivity in glacier rives from Vatnajökull glacier (South-West) and the rivers that normally flood from Skaftárkötlum cauldron. It has not been confirmed that glacier flood has started yet.

At the moment it has not been confirmed that glacier flood has started, but it might start soon. I am going to post more information once I have them or when they are published.

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