Monitoring – Page 97 – Iceland geology

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.

June 1, 2015

Alert level for Bárðarbunga volcano lowered

Today (1-June-2015) the alert level around Bárðarbunga volcano was lowered to uncertainty level from danger level. This means there are no longer any travel restrictions in the area. Besides normal spring closure in the highlands due to the snow melting (and creating mud areas). There is a risk of snap floods in the area due to hydrothermal activity in Bárðarbunga volcano. It remains high according to the latest news. The risk area for that melt water is in Jökulsá á fjöllum glacier river, since melt water can collect under the glacier and then flood the river days to weeks later. It is also not known what is going to happen when the summer melt period starts in Jökulsá á fjöllum glacier river. A new lake might from in the area next to the glacier where the lava blocked the glacier river path, the glacier water comes from Dyngjökuli glacier.

Icelandic News about this

Frá hættustigi á óvissustig (mbl.is, Icelandic)
Ekki lengur hættustig vegna Bárðabungu (Rúv.is, Icelandic)
Viðbúnaður vegna jarðhræringa við Bárðarbungu færður niður á óvissustig (Vísir.is, Icelandic)

May 30, 2015May 30, 2015

Strong earthquake swarm in Krýsuvík volcano

Yesterday (29-May-2015) there was a strong earthquake swarm in Krýsuvík volcano. Largest earthquake had the magnitude of 4,0, a smaller magnitude 3,1 earthquake also took place.

Green star shows the location of the magnitude 3,1 and 4,0 earthquakes. Copyright of this image belongs to Icelandic Meteorological Office.

Other earthquakes in this swarm where smaller, total of 97 earthquakes where recorded. Earthquakes swarms in this area are common, since the volcano has been inflating and deflating for the past few years. I don’t know if this earthquake swarm was related to such movements, since tectonic forces often create strong earthquake swarms in this area and along the Reykjanes peninsula and Reykjanes ridge.

The earthquakes as they appeared on my geophone in Heklubyggð. This image is under Creative Commons licence. Please see CC Licence page for more details.

On the geophone shut-down

There has been some discussion about me turning off the geophone network in Iceland. There is one station renaming in Heklubyggð and that station is going to continue to run for some time now (it doesn’t use the 3G network in Iceland). When it turns off I do not know. Besides 3G connection costs that have been going up in Iceland for the past few years, it has also become more expensive for me to fix the computers if they fail, along with 3G signal leak and other issues. It is also time consuming to run a remote network. I do help people if asked on what to buy in terms of hardware if they want to start there own geophone or seismometer. I don’t plan on stop recording earthquakes, I just plan on doing that just from my home once I am back in Denmark.

As for sensitivity of such hardware, it depends on what type of hardware is being used. Geophones are good for local earthquakes but more sensitive hardware is needed to record earthquakes at longer distance, like the magnitude 6,8 earthquake in Alaska this morning. It can be viewed here for the next few hours on long period seismometer (the top one and few others).

May 26, 2015

Böðvarshólar geophone station goes off-line on 28-May-2015

I am going to turn off the geophone station in Böðvarshólar on 28-May-2015. The only renaming geophone stations after this is going to be in Heklubyggð. I don’t know for how long I am going to keep it running. The Böðvarshólar geophone station has been recording earthquakes since 2012. It has however proved to be difficult to keep running remote geophone stations due to connection issues, hardware issues and so on. I have also been having a major problem with the 3G signal leaking into the recording and creating a problem (this was a huge problem this winter with all the snow). It was clear from the start that I would not be able to maintain a remote network forever. This was and always has been a temporary network. In the time I have been running this network. I have collected so much data that I am yet to properly work with it, install magnitudes, depths and locations in the data files. At the moment I got around of five years worth of unprocessed data. There is also a change taking place where this geophone is hosted. Changes that are outside of my control and I have nothing to do with them.

I won’t stop recording earthquakes, but since I won’t be living in Iceland I am only going to record earthquakes in Denmark and mostly long distant one [magnitude 6,0 and larger]. That is going to mean fewer earthquakes that I record each week and over the year (Denmark has few local earthquakes). The data is going to be easier to process at the same time due fewer recorded earthquakes that I have to handle. The only geophone station that I am going to continue to run for now is the one in Heklubyggð, how long it is going to remain on-line I do not know. That depends a lot on the person that owns the summerhouse where it is hosted. I hope everything understand why I have to turn my geophone network down in Iceland. Things are also changing for me personally and that change might not allow me to run this geophone network in the future. As I say above, I won’t stop recording earthquakes, I am just going to do with in a different way.

My geophones can be viewed here. Heklubyggð geophone doesn’t update at the moment due to failed WLAN transmitter (it is frozen). I am going to replace it soon with a new WLAN transmitter. The current WLAN transmitter is close to 10 years old (2007 or 2008) so it has started to fail due to old age and usage.

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 11, 2015

Small glacier flood from Grímsfjall volcano caldera

Today (11-May-2015) a glacier flood started from Grísmfjall volcano caldera. This is not a dangerous glacier flood due to its small size. There is however a danger from sulphur gases and other gases that dissolve when the pressure is dropped on the water. If people get too close to the Gígukvísl glacier river where the flood comes from Vatnajökull glacier they risk a damage to there eyes and lungs due to burning effects from the gases in the air.

Increased harmonic tremor from Grímsfjall volcano. Copyright of this image belongs to Icelandic Met Office.

There is now a increased harmonic tremor from Grímsfjall volcano. It is not clear why that is, it is either the glacier flood or hydrothermal vents boiling at the bottom of the lake due to the sudden pressure release on them. There is nothing suggesting that an eruption is going to follow this glacier flood from Grímsfjall volcano. Last glacier flood took place in 2014.

Icelandic News

Lítið hlaup í Gígjukvísl (Rúv.is, Icelandic)

May 2, 2015May 2, 2015

Earthquake activity in Askja volcano

During the week there has been a swarm of minor earthquakes in Askja volcano. All of the earthquakes have been small and none have reached magnitude 2,0 far as I know.

Askja volcano is the volcano most south on this image (the volcano on the end). Copyright of this image belongs to Icelandic Met Office.

There is nothing suggesting that current earthquake swarms are due to magma movements at shallow depths. This is rather hydrothermal activity changes in the volcano due the it being warmed up by new magma entering it and warming up groundwater inside the volcano. That has happened before in earlier eruptions and is documented, the time scale of such changes is not documented far as I know.

Askja volcano started for prepare for an eruption phase in 2010, so far nothing suggest that an eruption is imminent, but it remains a question if the push from Bárðarbunga volcano has changed anything in Askja volcano.

Article updated at 18:56 UTC.

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 28, 2015April 28, 2015

Earthquake swarm on Tjörnes Fracture Zone (TFZ)

Since yesterday (27-April-2015) at least there has been earthquake swarm taking place in Tjörnes Fracture Zone (TFZ). This earthquake swarm had a peak in activity during the night. Total of 64 earthquakes have been recorded so far, it is unclear of this earthquake swarm is over at this moment.

The earthquake swarm in TFZ. Copyright of this image belongs to Icelandic Met Office.

Largest earthquakes in this swarm had the magnitude of 2,8 and 2,9. Depth of the earthquakes in this swarm was around 13 km. This does look like a tectonic activity and there is nothing suggesting this is a earthquake swarm of volcanic origin. Earthquake activity in this part of Iceland is common.

Article updated at 13:58 UTC.
Article updated at 16:12 UTC.
Article updated at 16:15 UTC.

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