On Monday 23-July-2018 there was an small earthquake swarm in Öræfajökull volcano. This type of earthquake swarm is a common activity at the moment. Around 100 to 200 earthquakes now happen in Öræfajökull volcano each week. Almost all of them are small and less than 1,0 in magnitude.
The earthquake activity in Öræfajökull volcano. Copyright of this image belongs to Icelandic Met Office.
Largest earthquake so far this week had a magnitude of 1,2 and it had a depth of 4,9 km. Other earthquakes where smaller in magnitude. When a earthquake swarm happens in Öræfajökull volcano it is because magma is pressuring it self upwards inside the volcano. Earthquakes far outside Öræfajökull volcano are because of stress changes in the crust and that re-activates fault lines in the area. This might increase as more magma collects into Öræfajökull volcano along with stronger magnitude. That process might take weeks or months from what it is today.
Today (20-July-2018) at 06:28 UTC a magnitude 3,4 earthquake was in Bárðarbunga volcano south-east part of the caldera. It was followed by several smaller earthquakes during the day. Earthquake activity is common in Bárðarbunga volcano at the moment, but rate of earthquakes happening continues to drop every 3 – 6 months. When earthquakes happen they are often larger in magnitude.
Earthquake activity in Bárðarbunga volcano, the green star is the magnitude 3,4 earthquake. Copyright of this image belongs to Icelandic Met Office.
There is a risk of larger earthquake in next few hours to 48 hours. If nothing happens after 48 hours there is unlikely going to be a another larger earthquake happening. The magnitude that can be expected is above 4,0.
Since yesterday (18-July-2018) there has been a deep earthquake swarm south-east of Bárðarbunga volcano. Earthquake swarm in this location are common and due to their depth are always the result of magma injection into the crust in this area.
Earthquake activity south-east of Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.
Most depth recorded in this earthquake swarm was 26,3 km and the shallowest was at 13,4 km depth. Error margin might be high in this location due to distance from SIL stations. Smaller earthquakes (magnitude 0,0 – 1,0) are harder to locate and give correct depth. Activity at this location is sometimes followed by a large earthquake in Bárðarbunga volcano (main). That doesn’t always happen. It is not possible to know if that is going to happen now.
Yesterday (14-July-2018) and during the night (15-July-2018) an earthquake swarm took place deep on the Reykjanes ridge. This appears to be been a minor earthquake swarm and largest earthquake only had a magnitude of 3,0. This earthquake swarm took place good distance from the SIL network so locations and magnitudes have larger error margins.
Earthquake swarm on the Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.
This earthquake swarm appears to be over. If any smaller earthquakes are happening in the area were the earthquake swarm took place they are not being detected by the SIL network due to distance. This earthquake swarm can start again without warning.
In a statement sent out yesterday (13-July-2018) by Department of Civil Protection and Emergency Management it is made clear that Öræfajökull volcano is now inflating at considerable rate.
At the moment the amount of magma accumulated inside the mountain is equal to the volume that accumulated inside Eyjafjallajökull volcano before it erupted in 2010. At the moment Öræfajökull volcano continues to collect magma and each time a magma injection happens into Öræfajökull volcano an earthquake swarm happens.
At the moment there are no signs that an eruption is imminent. That might change without warning but I do expect to see earthquakes in the thousands before an eruption happens in Öræfajökull volcano. Until then its just normal monitoring of Öræfajökull volcano earthquake patterns and inflation.
During the night of 13-July-2018 a minor earthquake swarm took place in south part of the caldera of Katla volcano.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.
Largest earthquake in this minor earthquake swarm was magnitude 2,9 and the second largest earthquake had a magnitude of 1,9. This earthquake swarm is over but new earthquake swarms might start without warning. July often marks the time when earthquake activity starts to increase in Katla volcano.
At 21:10 UTC a earthquake swarm started in Tjörnes Fracture Zone just north of Gögurtá. Largest earthquake so far had a magnitude of 3,7. Other earthquakes so far have been smaller in magnitude so far. That might change without warning.
The earthquake swarm in TFZ. Green star is the magnitude 3,7 earthquake. Copyright of this image belongs to Icelandic Met Office.
There is some mislocation on the map at the moment due to the automatic location system at Icelandic Met Office website.
Since my geophone at Böðvarshólar is down due to a failed computer and I cannot afford Raspberry shake sensor (weatherproof type) only the largest earthquakes are going to be recorded at Dellukot geophone.
A massive landslide has fallen in western Iceland from a mountain called Fagraskógarfjall. This landslide is estimated to be 2 km wide and 1,5 km long at earlier measurements. I don’t know yet much material did push forward in this landslide but the amount is considerable. This landslide blocked a nearby river and a small lake is currently forming. It is expected that the river is going to form a new pathway past this landslide in next few hours to days. This might be largest landslide or among the largest landslides in Iceland since the year 1000.
Images, maps and videos on Icelandic News media (all text and interviews are in Icelandic and no English text available)
„Með stærstu skriðuföllum eftir landnám“ (Rúv.is, video)
Stór grjótskriða stíflar Hítará (Rúv.is, image, audio interview in Icelandic)
Drónamyndir úr Hítardal (Rúv.is, video)
Breytir landslaginu í Hítardal (Rúv.is, image, embedded facebook video)
„Þetta er bein afleiðing af þessum miklu rigningum“ (Vísir.is, image, video)
Drónamyndband frá skriðunni í Hítárdal (Vísir.is, video)
Ekki fyrirboði fyrir fleiri skriðum (Rúv.is, map)
Article updated at 19:11 UTC on 8-Juli-2018. Added new news item in Icelandic.
During the last few hours there has been ongoing earthquake swarm in Öræfajökull volcano. This earthquake swarm started around 29-June-2018 in the south side of Öræfajökull volcano. At the moment the earthquake activity seems to be close or directly under Road 1 in Iceland.
The earthquake activity in Öræfajökull volcano on 3-July-2018. Copyright of this image belongs to Icelandic Met Office.
This change in earthquake activity is interesting and is in my view a sign of trouble to come. There are not any older eruption vents in the side of Öræfajökull volcano, but such vents might have been wiped out by glacier over the centuries. There is a good reason to continue to monitor this earthquake activity in Öræfajökull volcano.
There is currently ongoing earthquake swarm in Öræfajökull volcano. This earthquake swarm started on 26-June-2018 with the magnitude 3,1 and it has been mostly ongoing since then. All earthquakes are minor in the volcano at the moment. A magnitude 2,1 earthquake happened outside the volcano (but those earthquakes appears to be connected to it) and suggest crustal stresses are changing at the moment at expectational speed (my view).
Earthquake activity in Öræfajökull volcano (red dots). Copyright of this image belongs to Icelandic Met Office.
What also appeared today is a earthquake swarm in the side of Öræfajökull volcano. If this earthquake activity continues it is worrying as it suggests that an eruption might happen in Öræfajökull volcano side and that might be a major issue if a eruption vents opens up in such area. Since this is close to Road 1 and warning time might be limited or close to none in worse case. This type of activity warrants more monitoring in my view.