Swarm – Page 76 – Iceland geology

October 23, 2015

Rare earthquakes in Hreppar micro-plate and other activity in Iceland

Due to family obligations I won’t be able to write a long post until Sunday (I hope). So here is a short overview of activity.

Hreppar micro-plate

A rare swarm of earthquakes took place on the Hreppar micro-plate today. All of the earthquakes had less magnitude than 1,0.

Hreppar micro-plate earthquake activity on its edge with the American plate. Copyright of this image belongs to Iceland Met Office.

South Icelandic Seismic Zone

A swarm of earthquakes took place in SISZ this week. Largest earthquake had the magnitude of 2,5 and was felt in nearby populated areas.

Earthquake swarm on SISZ. Copyright of this image belongs to Iceland Met Office.

Bárðarbunga volcano

Last week a magnitude 3,2 earthquake took place in Bárðarbunga volcano. This don’t appear to be deflation earthquakes, they rather look like inflation earthquakes. I don’t have time to write about it now, so details have to wait for now.

The magnitude 3,2 earthquake in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

I hope to write more on Sunday if I have time.

October 11, 2015

Overview of week 41 activity in Iceland

Week 41 in Iceland was rather quiet, compared to last two weeks in Iceland. Here is a overview over the highlight in the earthquake activity in Iceland.

South Iceland Seismic Zone (SISZ)

Constant earthquake activity has been in SISZ over the week and it has been ongoing for the past weeks, none of the earthquakes have been large, with almost all of them being less then magnitude 1,0. Largest earthquake in this swarm had the magnitude of 2,5.

The earthquake activity on SISZ. Copyright of this image belongs to Iceland Met Office.

Bárðarbunga volcano

For most part earthquake activity in Bárðarbunga volcano was normal this week, with regular earthquake swarms taking place in the usual places. The most interesting earthquake this week took place under Trölladyngju, it was only magnitude 0,7, but it was on depth of 26,2 km.

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

Herðubreið

Earthquake swarm has been taking place all week in Herðubreið. Earthquake swarms are common in this area and often have magnitude 3,0 earthquakes or larger. The earthquake swarm is ongoing when this is written.

Earthquake activity in Herðubreið/Herðubreiðarfjöll area (north of Askja volcano). Copyright of this image belongs to Iceland Met Office.

Reykjanes ridge

A magnitude 3,4 earthquake took place deep on the Reykjanes ridge this week. The earthquake was not felt and there might have been more than one earthquake. My geophone in Heklubyggð shows more than one earthquake one hour after the magnitude 3,4 earthquake happens.

Earthquake activity on the Reykjanes ridge. Copyright of this image belongs to Iceland Met Office.

A magnitude 3,0 earthquake also took place around 200 km off the coast of Reykjanes peninsula (around 153 km south of Eldeyjarboða). That earthquake location was poor due to the distance from the SIL network.

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October 4, 2015

Glacier flood from Skaftárkatlar cauldrons and other updates

This is going to be a short article since I don’t have a time to write a long one.

The glacier flood from Skaftárkatlar cauldrons is mostly over. There continues to be a lot of water in rivers that were flooded, with the flood peak being at 2200 m³/s (uncorrected). Some damage has taken place on roads and few bridges, with one major bridge almost collapsing from the river eating into the river banks. A graph showing this glacier flood in realation to older glacier flood from the eastern skaftárkatlar cauldron can be found here (Icelandic news). The glacier water that did flood into a lava field (that erupted from Laki) is still on its way and is going to reappear in few days as clean water, a lot of clean water that might create problem in nearby rivers and nearby roads if any exist. I don’t know the layout of roads and such in this part of Iceland so I don’t release what type of damage might happen. Image of the largest damaged bridge can be found here (Icelandic news), there is a video in this news.

Bárðarbunga volcano

There has been a slight increase in earthquake activity in Bárðarbunga volcano this week. A magnitude 3,1 earthquake took place along with little increase in smaller earthquakes. There have also been clusters of small earthquakes been appearing in east and in south (both east and west) part of the volcano. This activity suggest that new magma is flowing into the magma chamber at depth and the pressure has increased. Maybe not to eruption levels at the moment, but that moment is getting closer as the time passes.

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

North Langjökull volcano (Hveravellir)

Earlier this week an earthquake swarm took place close to Hveravellir (volcano). This earthquake swarm was not large and the largest earthquake only had the magnitude of 2,5 (or around that number. I was working when this happened and I did not have chance to check or save the data). Earthquake activity in this area has been increasing slowly for the past 10 years. It is unclear why that is happening.

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

Western Fracture Zone

There has been for the past few days earthquake activity in WFZ. This earthquake activity appears to be taking place in a extinct volcano in this area. I don’t think that this volcano is named and I don’t know the name of the mountains at the location were the earthquake activity is taking place.

The earthquake activity in WFZ today (04-October-2015). Copyright of this image belongs to Iceland Met Office.

I do expect the earthquake activity to continue in this area for next few days. Due to how rare earthquakes are in this area there is a risk of sharp and strong activity. It might also last for a long period of time, up to weeks or months at the longest.

Donations

Please remember to support my work with donations. At the moment I’m trying to collect as much money as I can before I move back to Denmark. I am also trying to save up for a cheap new laptop so that I can write when I am traveling, in the case anything happens in Iceland. It is going to cost me 40.000,00 ISK (~280€/315USD). Currently I’m doing full workday until the end of October (when not in school). To clarify, the work is hard and they only pay legal minimal wages and overtime pay (1 – 3 hours each day).

Thanks for the support.

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 22, 2015

Earthquake activity in Katla volcano

Today (22-September-2015) there was an swarm of earthquakes in Katla volcano at shallow depth. Largest earthquake had the magnitude of 3,3 with the depth of 0,1 km. The earthquake looks long period from the looks of my geophone at low resolution (I will get the higher resolution back when my main earthquake computer is back on-line). Other earthquakes in this swarm were smaller in magnitude.

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

Last week there was a swarm of earthquakes at 15 – 24 km depth (about) in Katla volcano. I did notice it and monitored it, I didn’t evolve into anything serious so I didn’t write about it. I don’t think the two activities are directly connected. This might be changes to the hydrothermal systems in the volcano or just normal activity for Katla volcano. At the moment I don’t see any changes in the volcano it self, even if there is deep earthquake activity taking place. For the moment, there is nothing to worry about.

September 21, 2015September 21, 2015

Earthquake swarm on the Reykjanes ridge

Today (21-September-2015) a minor (so far) earthquake swarm has been taking place on the Reykjanes ridge. Largest earthquake so far had the magnitude of 3,5 so far other earthquakes have been smaller in magnitude.

The earthquake swarm on the Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

It is difficult to know for sure what happens. Earthquake swarms in this part of the Reykjanes ridge often end quietly, but they can also just pick up as easily, it is impossible to know for sure.

September 21, 2015September 21, 2015

Increased activity in Bárðarbunga and Tungnafellsjökull volcanoes

I don’t have the time or the energy to write a long article about what is going on in Bárðarbunga and Tungnafellsjökull volcanoes. What I do know is that magma appears to be pressuring Tungafellsjökull volcano, creating earthquakes, the largest earthquakes so far have reached magnitude 2,9. Other earthquakes have been smaller. Some of the earthquakes appear volcanic in nature based on what I’m seeing on my geophones (at poor resolution at the moment).

In Bárðarbunga volcano there has also been earthquake activity today. I don’t know yet if its due to inflation or deflation of the magma system in Bárðarbunga volcano. Largest earthquake today (21-September-2015) had the magnitude of 3,2. Other earthquakes have been smaller, this earthquake activity has been small so there is a chance this does not mean anything yet.

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

The activity in Tungnafellsjökull volcano is likely to continue and might increase. I’m not sure what happens in Bárðarbunga volcano at the moment.

Working schedule: In September and until end of October I’m working Monday to Friday from 07:00 – ?? (Monday/Wednesday/Friday) and 10:00 – ?? (Tuesday/Thursday). Due to the nature of the work (its a slaughterhouse work) I don’t have my mobile phones with me and therefor I don’t know what is going on if anything happens. The longest days are now in process and are going to last until second or third week of October I think.

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.

September 11, 2015

Earthquake activity on the Reykjanes ridge

Yesterday (10-September-2015) there was an earthquake swarm on the Reykjanes ridge. This earthquake swarm was small and the largest earthquake only had the magnitude of 3,1. Other earthquakes where smaller in magnitude.

Earthquake activity on the Reykjanes ridge. Copyright of this image belongs to Iceland Met Office.

There is a chance of more earthquake activity in this area, since earthquake swarms on the Reykjanes ridge often start slowly.

September 5, 2015September 5, 2015

Overview of the small earthquake swarms in Iceland

Over the past few days there have been few minor earthquake swarms taking place in Iceland. None of the earthquake swarms have been large, all of them have been minor and no earthquake did reach the magnitude of 3,0 or larger.

The earthquake swarms in TFZ, Reykjanes peninsula and Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

Most of the earthquake activity that has been taking place has been happening in Bárðarbunga volcano, minor earthquake activity has been ongoing in the volcano and fissure since end of the eruption in February-2015. A swarm of small earthquakes took place on TFZ, none of those earthquakes reached magnitude 2,0. Most depth in this swarm was around 22 km, so magma might have been involved, this area is a rift valley. I don’t know of any documented eruption at this location, that does not mean it might not have happened. Minor earthquake swarm took place on the Reykjanes peninsula, one earthquake reached magnitude 2,8 with other earthquakes having smaller magnitude . The earthquake swarm took place in the volcano system of Krýsuvík. This earthquake swarm appears tectonic in nature rather then volcanic.

There has also been a minor earthquake swarm in Torfajökull volcano, it has been on the none-volcanic area between Torfajökull and Katla volcano. It’s unclear why this is happening, there is a chance this is a earthquake swarm in Katla volcano on the edge of the volcano system, or this is a earthquake swarm on the edge of the Torfajökull volcano system. I don’t have my maps so I can’t check for it.

Other then this it has been quiet in Iceland this week and for the past few weeks, this quiet might continue for the next few weeks to months.

Article updated at 23:45 UTC.

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