Dyke intrusions – Page 42 – Iceland geology

April 27, 2014May 3, 2014

Minor earthquake swarm in Bárðarbunga volcano

Yesterday (26-April-2014) and today (27-April-2014) an minor earthquake swarm took place in Bárðarbunga volcano. I am not sure if this earthquake activity is due to dike intrusion or normal tectonic activity.

Minor earthquake swarm in Bárðarbunga volcano. Copyright of this belongs to Icelandic Meteorological Office.

This area of Bárðarbunga volcano is well known for high earthquake activity. If this is an dike intrusion as is an possibility, it does not increase the risk of an eruption, since dike intrusion without starting an eruptions are a common feature in Icelandic volcanoes.

April 4, 2014

Earthquake swarm on Reykjanes ridge

During the night (4-April-2014) an earthquake swarm took place on the Reykjanes Ridge. Largest earthquake in this swarm had the magnitude of 3,5 and was felt on land according to information from Icelandic Meteorological Office. This earthquake swarm might still be ongoing, but it only lasted for about 1 hour last night. That is not really long period of activity for an earthquake swarm in this area. It is possible to monitor the earthquake here on my webicorder website. I am going to remove the test card images once I have my Gentoo Linux up and running in few days time.

The earthquake swarm on the Reykjanes Ridge. Green stars mark earthquakes with magnitude larger than 3,0. Copyright of this image belongs to Icelandic Meteorological Office.

Unconfirmed information in news on Rúv.is suggest that this earthquake swarm might have its origin in magma movement at this location. Rather than tectonic activity at the same area. This area often has powerful earthquake swarms. Earthquake swarms in this area often drop in activity for few to several days at the time, before they resume at even more powerful then before. I don’t know if that is going to happen now, there is an good chance that is going to happen now or this might just be it. All that can is possible to do at the moment is to wait and see what happens next.

Update on the hard drive saga: So I did buy a new hard drive. When I did try to use it I found out that the drive I had bought was faulty from the factory. The store has already ordered an replacement hard drive and I should get it on Monday. I hope this issue is resolved by then. I have already received donations to support buying this new hard drive. But that does not mean my financial status is good this month. But it is far better now than in April or the months before it. Thankfully. Thanks for the support. I am currently using my Windows XP (normally just used to play games) hard drive to write this while my Gentoo Linux is out of commission due the hard drive failure.

March 28, 2014March 28, 2014

Earthquake swarm in Grímsfjall volcano

Today (27-March-2014) an earthquake swarm took place in Grímsfjall volcano. This activity is connected to current minor glacier flood from Grímsvötn glacier lake that is now taking place. The glacier flood it self is an minor and is about the same size as an glacier flood from Grímsvötn glacier lake in November-2012.

Earthquake activity in Grímsfjall volcano today (27-March-2014). Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor has been increasing in Grímsfjall volcano following this glacier flood. The leading idea is that the glacier flood is creating this high frequency harmonic tremors. This idea however remains unconfirmed at current time.

Harmonic tremor at 21:13 UTC on 27-March-2013 at Grímsfjall volcano. The harmonic tremor starts at the end of this plot. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor at 22:55 UTC on 27-March-2014. As can be seen the high (blue line) harmonic tremor is increasing at the moment. Copyright of this image belongs to Icelandic Meteorological Office.

At present time there is nothing to suggest that an eruption has or is about to start in Grímsfjall volcano. However Grímsfjall volcano is unpredictable and highly active when it comes to eruptions. If an eruption starts in Grímsfjall volcano it might do so without an warning. Earthquake activity in Grímsfjall volcano would increase sharply just before the eruption would start as was the case before the eruption in 2011 (covered here). More detailed monitoring can of Grímsfjall volcano and other volcanoes in Vatnajökull glacier can be found here (Icelandic).

Advertisement: As I did say few days ago. I am adding advertisement back to my websites. Since I need to eat and pay the bills. There however has been a minor issue with my Google Adsense account. An issue that has so far not yet been resolved by Google. Once its resolved I am going to go trough the process of getting my account approved again. I was too detailed back in January when I closed down my Google Adsense account. I hope to have advertisements back before some volcano erupts in Iceland.

March 22, 2014March 22, 2014

Deep earthquake in Hamarinn volcano

Yesterday (21-March-2014) an extremly deep earthquake took place in Hamarinn volcano (part of Bárðarbunga volcano often called Loki-Fögrufjöll). The magnitude of this earthquake was just 1,4 but its depth was around 29,7 km. The location of this earthquake was just 10,4 km North-East of Hamarinn volcano (main). So it possibly was inside Hamarinn main volcano system, but I am not sure on that detail.

The earthquake activity in Hamarinn volcano and Öræfajökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquakes that take place this depth happen due to magma movement or small dike intrusion at depth. I don’t know what is the actual case here, this might just be an earthquake at depth. The crust has the depth of 40 km at this location (study on this can be found here) due to hotspot [second link here] activity that has increased the thickness of the crust. Last eruption in Hamarinn volcano was in July 2011, it was an minor eruption that took place and lasted just for few hours and did not breach the glacier.

Post updated at 21:02 UTC.

November 27, 2013November 27, 2013

Harmonic tremor detected in Þórðarhyrna volcano

On the 21-November-2013 there was an earthquake swarm in Þórðarhyrna volcano (part of Grímsfjall volcano). This was not large earthquake swarm or a strong one. With the largest earthquake just having the magnitude of 1,9. While I did just suspect it I did not have it confirmed until today that following this earthquake swarm was an harmonic tremor pulse. This harmonic tremor lasted from 03:30 to 06:10 UTC. Based on nearby SIL station this was not a strong harmonic tremor, but this is important because it suggests that something is taking place in Þórðarhyrna volcano. If this is going to lead to an eruption is unknown at current time. This might be a dike intrusion into the volcano at depth, but that has not been confirmed.

The harmonic tremor pulse can be seen at 21-November date on this tremor plot from Icelandic Meteorological Office. Copyright of this image belongs to Icelandic Meteorological Office.

The harmonic tremor pulse as it did appear from Grímsfjall SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor pulse as it did appear on Jökulsel SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

This activity might not lead to an eruption, but given the past history of this area and the eruption in Grímsfjall volcano in the spring of 2011 I find it to be highly likely outcome that eruption is going to take place in Þórðarhyrna volcano in near future, it is not possible to know when such eruption might take place. Last eruption took place in Þórðarhyrna volcano in the year 1902, it is not known if any later eruptions have taken place in Þórðarhyrna volcano.

Blog post updated at 14:47 UTC.

November 24, 2013November 24, 2013

Earthquake swarm in Tungnafellsjökull volcano

There is currently ongoing interesting earthquake swarm activity in Tungnafellsjökull volcano. This earthquake activity appears to be taking place due to magma injection at depth into the volcano. Currently the earthquake activity doesn’t appear so clearly on the Icelandic Meteorological Office earthquake maps. I am not sure why that is, the largest earthquake so far has had the magnitude of 2,3 at the depth of 0,5 km so activity is already rather shallow, deepest activity had the depth of 17,5 km. Earthquake activity started in Tungnafellsjökull volcano in the year 2012, before that earthquake activity had taken place in Tungnafellsjökull volcano following an eruption in Bárðarbunga / Grímsfjall volcano in the year 1996 [map here of Week 41 – 1996]. Current earthquake activity is not based on any such event.

Earthquake activity in Tungnafellsjökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Tremor activity showing minor earthquakes taking place in Tungnafellsjökull volcano (most likely) over the past few hours. Copyright of this image belongs to Icelandic Meteorological Office.

I am not sure yet what is happening in Tungnafellsjökull volcano. But data in mounting and suggesting that magma is about to start flowing into the volcano at faster rates then before (via dike intrusions). Tungnafellsjökull volcano has not erupted in historical times (at least no eruption is documented) so it is impossible to know for sure what happens next in this volcano. If an eruption where to take place it would be mostly basalt based on post sub-glacier eruptions (when they erupted is not known). Current earthquake activity might die down as it did in the year 2012 when (and earlier this year [2013] also) this swarm like activity at depth (15+ km) started to happen.

Blog post updated at 04:36 UTC.
Blog post updated at 04:46 UTC.

November 17, 2013November 17, 2013

Minor earthquake swarm in south-east of Katla volcano

Today (17-November-2013) a minor earthquake swarm took place in Katla volcano at 06:21 UTC and it lasted to 07:09 UTC. The largest earthquake has the automatic magnitude of 1,8 with the depth of 18 km. This earthquake swarm took place under an former island in the area called Hjörleifshöfði (in Deutsch, English is not available). It is possible that this former island has it’s origin is in an volcano activity in the area, while I do not have it confirmed it is at least an idea. The deepest earthquake in this area had the depth around 22 km according to automatic results from Icelandic Meteorological Office.

131117_1815 — The earthquake activity in the east part of Katla volcano system. *Copyright of this image belongs to Icelandic Meteorological Office*.

Based on the depth of this earthquake swarm, the origin of this earthquake swarm was in magma movement or dike intrusion. It is not a tectonic activity, since such earthquakes are not so common in this part of Iceland, but they do happen. I am not sure what this means for activity in Katla volcano since I have not seen this before as it appeared now. This area of Iceland can be viewed in Google Maps and with Street View here.

October 11, 2013October 12, 2013

Source of the glacier flood in Hofsjökull volcano found

In August-2013 there was an glacier flood from Hofsjökull volcano, this glacier flood was minor and did not cause any damage. The source of this glacier flood has now been found according to Icelandic Meteorological Office. A new glacier cauldron has been found in Hofsjökull glacier, where none was before. The cauldron is around 700 meters long and about 30 – 50 meters deep. The glacier is cracked a lot around the cauldron and it’s dangerous to travel to this area because of that. The hight of this cauldron is around 1700 meters above sea level.

Hofsjökull volcano and glacier. The new glacier cauldron is located at ~64°49,5‘N; 18°52‘W. Click on the image for full resolution. Image from NASA/USGS/Icelandic Meteorological Office/Geological Department of University of Iceland (Jarðvísindastofnun Háskólans).

According to Icelandic Meteorological Office this part of the glacier has not had any glacier cauldrons before that they know of. This cauldron has the volume of 1 million cubic meters (10⁶ m³) according to Icelandic Meteorological Office. This area now has highly active hydro-thermal area and hot-springs. What formed this glacier cauldron is unclear at the moment, it was not an eruption since no such signals have been recorded from Hofsjökull volcano before or after the glacier flood in August-2013. It is also unclear if this glacier cauldron is going to create new glacier flood in the future.

Icelandic Meteorological Office announcement

Hlaup úr Hofsjökli í ágúst 2013 (vedur.is, in Icelandic)

Icelandic News

Fundu sigketil á Hofsjökli (mbl.is, Icelandic)

Blog post updated at 21:02 UTC on 11-October-2013.
Blog post updated at 01:45 UTC on 12-October-2013.

October 3, 2013

Fewer earthquakes taking place on Tjörnes Fracture Zone at the moment

Donation note: I still need donations for October. I currently have no money for anything and that is rather bad. This bad situation that I am having is going to last for several months according to an excel document that I have set-up to figure out my total debt repayment. I can repay my debt (or buy replacement hardware if anything fails), but not buy food at the same time. The exchange rate of ISK to DKK is also bad at the moment. I hope for improvement but that won’t happen for next several months at least.

Activity in Tjörnes Fracture Zone continues as it has been doing for the past week. There is not a lot of other activity taking place in Iceland at the moment. The largest earthquake today (03-October-2013) had the magnitude of 3.5, a second earthquake with the magnitude of 3.1 also took place in TFZ today. Depth of this earthquake swarm remains the same, around 5 to 15 km at current time.

The largest earthquakes in this earthquake swarm in TFZ. Image in original context can be found here (Icelandic). Copyright of this image belongs to Icelandic Meteorological Office.

Today (03-October-2013) there were fewer earthquakes in this swarm than yesterday. The drop is currently around half of less activity than yesterday. I am not sure why this is as currently the earthquake swarm is ongoing. Even if there are fewer earthquakes taking place. This might just be a short time drop in earthquake activity, or this might signal an end of this earthquake swarm. Currently it’s too early to know for sure. The only thing that can be done is to wait and see what happens next in this earthquake swarm.

Earthquake activity today on Tjörnes Fracture Zone. Copyright of this image belongs to Icelandic Meteorological Office.

So far there are no signs of any magma having reached the surface, if that is the reason for this earthquake swarm in this area of Tjörnes Fracture Zone.

October 3, 2013October 3, 2013

Update on Tjörnes Fracture Zone earthquake swarm

Donation note: I still need donations to survive this month as any other months while I am just on social welfare from Iceland as I have explained here. This month I just have around 24 DKK (3.21€) for food this month after paying all the bills and my debt. I have already got some donation, but they just allow me to buy food for about one and half week if I am smart. Thanks for the help.

The earthquake swarm on Tjörnes Fracture Zone continues. The earthquakes are getting stronger, with the largest one today having the magnitude 3.8 (automatic results) and five other earthquakes with the magnitude 3.0 to 3.2. Currently the depth is around the same, it remains at 5 to 15 km and at the moment it doesn’t seems to be changing. Rate of earthquakes is around the same today (02-October-2013) as it was yesterday (01-October-2013), with no major changes in earthquake rate from what I can see currently taken place.

Earthquake activity in Tjörnes Fracture Zone. Green star show earthquakes larger than magnitude 3.0. Copyright of this image belongs to Icelandic Meteorological Office.

All earthquakes above magnitude 3.0 have been felt in Siglufjöður and Ólafsfjörður towns and other populated areas that are close to this earthquake swarm. There are no signs of this earthquake swarm slowing down as is. It still has not been confirmed if this earthquake activity is connected to magma injection at depth, or if this is just normal tectonic earthquake activity in this area. It’s going to remain difficult to confirm this idea until an eruption starts in this area and that simply might just not happen at all. The largest earthquakes appear on my webicorders website here, on the geophone station named Böðvarshólar.

Blog post updated at 22:33 UTC on 02-October-2013.
Blog post updated at 22:39 UTC on 02-October-2013.

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