The earthquake on 20-October-2020 was followed by a strong inflation in Reykjanes volcano. Current levels of inflation are about ~50mm according to Icelandic Met Office and can be seen on GPS measurements in recent days (GPS time series for Reykjanes).
The inflation in Reykjanes volcano. I had to scale this image because of WordPress requirements. Full size image can be found here on Icelandic Met Office website. Red is more inflation, blue is deflation or lower areas. Copyright of this image belongs to Icelandic Met Office.
This inflation appears clearly on GPS stations that are closest to this area. The area where the most inflation is a small mountain called Keilir. Last eruption in this area was sometimes during last ice age. This inflation also explains the earthquake activity that has been going on in this area for the last few days as I have written earlier about.
Current earthquake activity on the Reykjanes peninsula. Detection of smaller earthquakes is lower because of bad weather in Iceland. Copyright of this image belongs to Icelandic Met Office.
As of the writing of this article I am expecting more earthquakes and more inflation to happen in this volcano and other close by areas. It is not possible to know when a eruption is going to happen in Reykjanes volcano.
Icelandic Met Office News
Significant ground deformation detected associated with recent earthquakes (en.vedur.is)
Today (24-October-2020) I noticed that there has been since yesterday (23-October-2020) a swarm of small earthquakes on what appears to be a west to east fault on the Reykjanes peninsula in the Reykjanes volcano. All of this earthquake activity is mostly just small earthquakes that don’t appear on the automatic map on Icelandic Met Office website. This earthquake activity only appears after a manual review that Icelandic Met Office has do. The total length of the fault that is in west to east direction seems to be 20 km to 30 km, it is difficult to be sure at the writing of this article.
The earthquake activity on the Reykjanes peninusla in the Reykjanes volcano. Copyright of this image belongs to Icelandic Met Office.
There are more faults at work in this. One or two fault are in mostly north-south direction and one fault is at southwest to northeast direction. There is also some cluster earthquake activity in Krýsuvík volcano but it doesn’t seem to have formed any fault like direction as of writing of this article. This changes seems to be supported by movement on the automatic GPS data from this area that can be viewed here (GPS time series for Reykjanes). It is difficult to be sure what happens next in this. There is now a storm passing over Iceland and that prevents detection and recording of the smallest earthquakes on the Reykjanes peninsula. The weather forecast for next week doesn’t look so good today (Saturday 24-October-2020).
It is a fact that not every eruption requires a big and strong earthquake swarm to start. I don’t know if that is true for Reykjanes volcano.
This is a short update.
Reports from yesterday (22-October-2020) on Stöð 2 (Channel 2) report that there is a strong smell of Sulfur dioxide from Grænavatn lake. Some increase in one hots spring in Krýsuvík volcano has been reported. That might because of change in water pathways in the crust because of the earthquake on 20-October-2020. New cracks have also formed and the earthquake caused small landslides on the coastline closest to the earthquake. The cracks in the ground are dangerous and people should not go to the coastline in this area of Iceland now. A new earthquake can happen at any time without warning.
Automatic GPS data is suggesting that in Krýsuvík volcano there has been a fast inflation of magma. I don’t think this is displacement because of the earthquake based on other nearby GPS stations.
Brún Krýsuvíkurbjargs sprungin og varasöm eftir jarðskjálftana (Stöð 2/Vísir.is, pictures, video)
Since yesterday (20-October-2020) the earthquake activity on the Reykjanes peninsula in the volcano Reykjanes or Krýsuvík volcano has been slowly getting down after the Mw5,6 earthquake. There have been at the writing of this article 30 earthquakes with magnitude that are larger than Mw3,0 in this area, some of those earthquakes have been felt in nearby populated areas.
The earthquake activity slightly more than 1 day later on the Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.
At the writing of this article the number of detected earthquakes in this swarm is getting close to 2000 earthquakes. The risk of stronger earthquake both west and east of the Mw5,6 earthquake that took place yesterday. Strongest possible earthquake in this part of Iceland can reach magnitude Mw6,5 to Mw6,7 depending on location and that is only east of current earthquake activity in Brennisteinsfjöll volcano area.
According to the news, the first injury because of the Mw5,6 earthquake has been reported along with damage to a viewing place in the mountain close the location of the earthquake yesterday.
Rotaðist þegar jörðin kipptist undan (mbl.is, pictures, Icelandic)
I am going to post updates soon as possible if anything more happens in this activity on Reykjanes peninsula. At the writing of this article there has not been any sign of magma movement or any sign that an eruption has taken place in this area.
It was reported by Icelandic Met Office at 22:20 UTC that people had been noticing more gas smell close to a small lake called Grænavatn. This suggest that magma might be on the move in the crust. It is currently difficult to be sure at writing of this article. This would be inside the volcano of Reykjanes.
Grænavatn lake. Copyright of this image belongs to Google Earth / Google.
Earthquake activity on the Reykjanes peninsula at midnight 21-October-2020. Copyright of this image belongs to Icelandic Met Office.
At the writing of this article there has not been any change in harmonic tremor on nearby SIL stations. If magma is about to move that is possibly going to happen without much warning but this difficult to know for sure at the writing of this article.
This is the last update for today (20-October-2020) on this earthquake unless something major happens.
This earthquake magnitude has been confirmed at Mw5,6 mostly. It might change in next few weeks as the data is better reviewed. More then 400 earthquakes have been felt after the large earthquake and at the writing of this article largest aftershock has automatic magnitude of Mw4,1.
Location of the largest earthquake. Copyright of this image belongs to Icelandic Met Office.
Currently the main earthquake activity is moving west or south-west and that might trigger more large earthquakes in next 24 – 48 hours. Minor damage has been reported following the largest earthquake. Items falling off shelves and in stores and homes, cracks forming in walls, floors and outside in few areas. Rock slides have also been reported and closed one road on Reykjanes peninsula close to Grindavík.
News reports with pictures and videos if the main earthquakes and the damage it created
Stór sprunga í gólfi flugskóla Keilis (mbl.is, picture)
Skjálftinn í myndum (frettabladid.is, pictures, videos)
Added: Vörur köstuðust til og maður í górillubúningi hljóp um (Rúv.is, Video, Icelandic)
Earthquake activity on Reykjanes peninsula
The earthquake activity at 18:45 UTC on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.
There have not been any clear sign or any sign of magma movement in this earthquake activity at the writing of this article. It is unclear of that is going to change since the magma that has been flowing into the crust in Reykjanes volcano simply might not be pressured enough to erupt for a while longer.
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Article updated at 20:06 UTC.
This is a short update on the earthquake activity on Reykjanes peninsula. Early magnitude calculation give this earthquake a magnitude of Mw5,6 but this number might change. Large aftershock activity is expected during the next 24 hours.
The earthquake activity on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.
A video recording of the earthquake from Alþingi shows the effect of this earthquake.
I’ll post more details later today when I have them.
Today (20-October-2020) at 13:43 UTC large earthquake with early magnitude of Mw5,5 took place close to Kleifarvatn lake in Krýsuvík volcano. I’ll write a second article with more details about this earthquake later today. This earthquake was felt in Reykjavík and over wide area of south Iceland.
Yesterday (17-October-2020) at 22:02 UTC an earthquake with magnitude of Mw3,3 took place 3 km north-east of Húsavík town in the Flatey – Húsavík fault. This was followed by few minor earthquakes. This earthquake was felt in Húsavík but no damage was reported from it.
The earthquake activity close to Húsavík. Copyright of this image belongs to Icelandic Met Office.
This area of the Flatey – Húsavík fault has not seen any earthquake activity until now, even if there has been a strong earthquake swarm going on in nearby areas since June 2020 . There continues to be a risk of stronger earthquakes in Tjörnes Fracture Zone.
Since 15-October-2020 there has been a slow increase in small earthquakes in Reykjanes and Krýsuvík volcanoes. This earthquake activity has been followed by changes in GPS location. The GPS data can be viewed at Reykjanes CGPS website. All the earthquakes at the writing of this article are small in magnitude. Last few weeks have been quiet in Reykjanes and Krýsuvík volcanoes and that is normal for this type of volcanoes.
The earthquake activity in the volcanoes Reykjanes and Krýsuvík. Copyright of this image belongs to Icelandic Met Office.
It is not possible to know how this is going to develop since what happens depends on the amount of magma moving and what that does. It is unclear if this is inflation or deflation event taking place. It might take few days to see what that is.