Today (30-August-2016) an earthquake swarm started in Bárðarbunga volcano. The earthquake swarm took place in the caldera of Bárðarbunga volcano, as has been the case for the past few months. Nothing suggests that magma is on the move or that eruption is imminent, this seems to be tectonic or tectonic related activity in Bárðarbunga volcano after the eruption in 2014, that ended in February 2015.
The earthquakes in Bárðarbunga volcano. Green stars are earthquakes larger then magnitude 3,0. Copyright of this image belongs to Iceland Met Office.
Largest earthquakes so far have the magnitude of 3,8 (at 13:33 UTC) and 3,4 (at 16:58 UTC), other earthquakes have been smaller in magnitude. The reason for this earthquakes is inflow of magma at depth (more than 10 km) into Bárðarbunga volcano. This is creating stress changes higher up in the crust, resulting in earthquake swarms. More earthquakes can be expected from Bárðarbunga volcano in next few hours to days. This type of earthquake activity almost happens weekly at the moment and that has been the activity pattern since September-2015. I’m not expecting any change in this activity pattern for next few months.
Yesterday (29-August-2016) an magnitude 3,4 earthquake took place on Reykjanes Peninsula, this earthquake was felt due to how close it was to populated area.
Green star shows the location of the earthquake. Copyright of this image belongs to Icelandic Met Office.
No other earthquakes have followed this earthquake. Some minor earthquake happened before the main earthquake, no other activity has happened after the main earthquake.
This is not going to be a too long update about the activity in Katla volcano. Since I fear that this article might become outdated rather quickly.
Currently there is no eruption in Katla volcano. At the moment only earthquake activity has happened. Latest information shows that hydrothermal water has entered Múlakvísl glacier river from Mýrdalsjökull glacier and that is making the air nearby possibly toxic and dangerous. The two largest earthquakes had the magnitude of 4,5. One earthquake had the depth of 3,8 km while the one that happened 20 seconds later had the depth of 0,1 km. Other earthquakes had magnitude around 3,0 and above and below.
Green star show where earthquakes with magnitude above 3,0 took place in Katla volcano. Copyright of this image belongs to Iceland Met Office.
It is not know how and eruption starts in Katla volcano, since no historical recordings exist when last eruption took place in the year 1918. Making ideas on how an eruption in Katla volcano start mostly guesswork. Current earthquake activity is the strongest since 1977, in 1955 there was some strong earthquake activity but magnitude of those earthquakes is not known. It is my idea that Katla volcano erupts when a rift zone activity takes place in this area, since it is on the eastern volcano zone (EVZ) in Iceland, it is currently expanding south of Vestmanneyjar and American plate and Euroasian plate is around 1cm/year.
The main 4,5 earthquake in Katla volcano. This image clearly shows a long period earthquake. This is my station in Heklubyggð. This image is under CC Licence, please see CC Licence page for more details.
The main 4,5 earthquake as it appeared on my geophone in Böðvarshólar. The earthquake signal is clear. This image is under CC Licence, please see CC Licence page for more details.
It is difficult to know what happens now. The signs are not good, but Katla is an active volcano with regular eruption cycles so this is only matter of time now. As mentioned above, the reason is lack of data on how the eruption process starts in Katla volcano. All that can be done now is to wait and see what happens next.
This article is going to be updated in the next 24 hours if needed. Details are few at this moment.
A magnitude 3,6 earthquake (automatic magnitude estimate) has happened in Katla volcano. Few other earthquakes happened before the largest earthquake and few minor earthquakes took place after it. At the moment activity has dropped down (as it appears on my geophone) to nothing. That might change without warning.
Earthquake activity in Katla volcano. This image does not have the magnitude 3,6 (automatic magnitude estimate) in it. Copyright of this image belongs to Iceland Met Office.
At the moment no harmonic tremor has appeared on the SIL stations around Katla volcano. This means that eruption has not started. Until an harmonic tremor appears, this is just an earthquake activity.
This article is going to be updated if needed in few hours (around 16:00 GMT/UTC due to my current day plan).
Today (26-August-2016) a minor earthquake swarm started on TFZ. This is currently not a large earthquake swarm and only around 50 earthquakes have happened so far. More earthquakes might happen if this earthquake swarm continues.
The minor earthquake swarm is shown by the cluster of red dots. Copyright of this image belongs to Iceland Met Office.
This area has seen several earthquake swarm since July and is a high chance earthquake activity is going to continue in this area for the next few days to weeks. Earthquakes with magnitude above 3,0 cannot be ruled out.
On the 18th of August 2016 a small glacier flood started from the Grímsfjall volcano caldera lake. This is a tiny glacier flood according to the news, with the glacier on top of the lake only having dropped around 5 meters so far.
Minor glacier flood as it appears on Grímsfjall volcano SIL station. Copyright of this image belongs to Iceland Met Office.
This glacier flood is going into Gígjukvísl glacier river, at the moment Iceland Met Office doesn’t think there is any major danger from this glacier flood. The biggest risk at the moment is from volcano gases that have dissolved into the water and get released when the pressure drops of the water. The glacier water is already in Gígukvísl glacier river, no major changes are expected in that river due to how small this glacier flood is.
Lítið jökulhlaup hafið úr Grímsvötnum (Rúv.is, Icelandic)
Jökulhlaup hafið úr Grímsvötnum (mbl.is, Icelandic)
Today (19-August-2016) a magnitude 3,5 earthquake took place in Katla volcano. It was followed by several earthquakes, both before the strongest earthquakes and after it.
The earthquake activity in Katla volcano. The green star shows the location of the magnitude 3,5 earthquake. Copyright of this image belongs to Iceland Met Office.
This doesn’t seems to be an activity connected directly to magma movements. This might however be a gas under pressure breaking rock, since clues this summer suggests that heat is now increasing in the caldera. At least for now, it might cool down again in coming months. The most common months for Katla volcano to erupt are from July until November, eruptions in other months are less common, they do happen every few hundred years.
The magnitude 3,5 earthquake as it appeared on my geophone in Heklubyggð. This image is under Creative Commons licence. Please see the CC Licence page (above) for more details.
I want to thank my readers for the patience and the understanding of the quiet period following the sudden passing of my step-father on 11th of July 2016. This past month has been difficult for me and my family and the recovery process is far from complete, but I’m doing my best to live with the new reality with my step-father.
Life is never going to be the same for me, this is however just how the world works and I’ll have to live with it.
This is an automatic article for 12th of August so people can continue to discussions if something is happening in Iceland.