Eruption at Litli-Hrútur might end in two weeks

Rúv News and Earth Science at University of Iceland is reporting that the eruption in Fagradalsfjall at Litli-Hrútur might end in one or two weeks time. This is based on how much the lava flow from the crater is currently decreasing. This would also be mostly in line with the eruption in Meradalir valley in 2021, that lasted for two weeks. This eruption has been slightly longer than that eruption, since it has been slightly larger in volume of magma erupting.

Icelandic reporting on this

Eru goslok handan við hornið? (Rúv.is, Icelandic)
Facebook post reporting on the details of the eruption for 29. July 2023 (Facebook, Icelandic, Possible English)

Update on the eruption close to Litli-Hrútur on 23. July 2023 at 21:22 UTC

This is a short update. Since there is not a lot of information about this.

  • The crater might collapse at any time without warning. Geologists that monitor the eruption have noticed that the crater has started to get larger and is now full of lava. This means it is going to collapse. What direction is not known. It is my view that it is going to collapse to the east because of least resistance in that direction.
  • When the crater collapses the lava is going to flow more than 100m/s in whatever direction it flows.
  • Tourists are in high danger close the crater because of this collapse risk.
  • Dyke intrusion has been detected east of Keilir mountain. Along with increased ground temperature, that means the magma is at shallow depth in the crust. This area might erupt soon in similar way as is now happening close to Litli-Hrútur.

This is all the information I have now and only thing that has changed in the eruption in the last 13 days.

Icelandic News

Veggir gígsins muni hrynja innan skamms (Vísir.is)

Strong earthquake 1,4 km east of Keilir mountain

Today (9. July 2023) at 22:22 UTC an earthquake with magnitude of Mw5,2 happened 1,4 km east of Keilir mountain. This earthquake did shake Keilir mountain and resulting a small dust cloud. This earthquake is connected to inflation that is happening just south of Keilir mountain, rather than being connected directly to magma movements in this area.

A lot of green stars close to Keilir and Fagradalsfjall on Reykjanes peninsula map. Time on map is 9th July 2023 at 23:15 UTC.
Strong earthquake activity in Fagradalsfjall mountain and Keilir mountain. Copyright of this image belongs to Icelandic Met Office.

There’s a risk of more strong earthquakes like this in this area until an eruption starts.

Update on activity in Fagradalsfjall – Keilir mountains on 9th July 2023 at 16:11 UTC

This is a short update, because there’s little to report.

  • Three earthquakes with magnitude above Mw4,0 took place north east of Keilir mountain in the last 24 hours.
  • Earthquake activity is increasing north-east and north of Keilir mountain. Why is unclear, it is a possibility that magma is creating a path for it self that way.
  • The magma seems stuck in the crust and there doesn’t seems to have stopped the inflow of magma from the deep mantle. This is going to result in increased pressure in the dyke until an eruption happens.
  • Risk of strong earthquakes is high and might get higher until an eruption starts.

 

Heavy earthquake activity remains in Fagradalsfjall - Keilir area. With the new activity area north-east of Keilir mountain. Time on map is 9 July 2023 at 15:55 UTC.
Heavy earthquake activity in Fagradalsfjall – Keilir mountain. Copyright of this image belongs to Icelandic Met Office.

Since the start of this activity, around 12000 earthquakes have been recorded by Icelandic Met Office according to the news. Strongest earthquake at the writing of this article is at magnitude Mw4,8.

Update on the activity in Fagradalsfjall mountain on 7th July 2023 at 14:28 UTC

This is going to be a really short article. Because an eruption might be about to start. Difficult to be sure, but there’s a chance. Eruption has not started at the writing of this article.

  • Largest earthquake in the last 24 hours seems to be a magnitude Mw4,3. I no longer can keep up with all this earthquake activity.
  • Inflation in area close to Keilir has reached 200mm (20cm) in less than 48 hours when this started.
  • Inflow of magma is estimated to be 88m3/s and that is a lot of magma moving and moving fast.
A lot of earthquakes in Fagradalsfjall mountain. Too many earthquakes too count and too many green starts.
Heavy earthquake activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

It is unclear where the eruption is going to happen. But there has been a drop in earthquake activity that strongly suggest that magma is close to finding a path to the surface. According to measurements, the magma is now less than 1 km away from the surface.

Update on activity in Fagradalsfjall mountain on 6th July 2023 at 14:20 UTC

This is a short update because there’s a lot going on.

  • Earthquake activity started to drop around 04:00 this night according to Icelandic Met Office and seems to continue to drop at the writing oft his article. This suggests that an eruption might be getting close in time.
  • Strong earthquakes might still happen even if earthquake activity is dropping.
  • Movement on GPS is close to 50mm in some locations. That’s a lot more than in earlier eruptions. When it was at most from 15mm to 25mm in some locations. Movement is not equal in all directions and location on GPS.
  • During the day the earthquakes started to move south again towards Fagradalsfjall mountain. At the same time, number of earthquakes dropped.
  • Here are the web cameras I know of as writing of this article. Rúv, Reykjanes North, Reykjanes south, Live from Iceland, Fagradalsfjall, Live from Iceland, Langihryggur, Morgunblaðið, Perlan.
  • It is impossible to know when an eruption starts.

 

A lot of green stars and red dots in Fagradalsfjall mountain and on Reykjanes peninsula because of misplaced earthquakes.
Strong earthquake activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

How long the wait until an eruption happens is impossible to know. Because of activity in this area in the last two years, the crust around Fagradalsfjall mountain and nearby areas is weak and can allow magma to pass more easily then it otherwise would. It remains a question if there’s some type of block that the magma can’t get trough close to Keilir mountain. Magma is always going to find path of least resistance and erupt at that location. That location is now somewhere between Keilir and Fagradalfjall mountains.

Update on Fagradalsfjall mountain activity at 16:35 UTC on 5th July 2023

This is a short update since there is a lot going on.

  • Largest earthquake recorded at the writing of this article is Mw4,8 from earlier this morning.
  • Larger earthquakes are growing in numbers. There is now also a warning for possible Mw6,3 earthquake on Reykjanes peninsula following this earthquake swarm and dyke intrusion into Fagradalsfjall mountain.
  • The dyke intrusion is coming up just south of Keilir mountain.
  • Based on what I am seeing, it is possible that current dyke intrusion into Fagradalsfjall mountain is larger than the first eruption in March 2021. If this is accurate is a wait and see situation until an eruption starts.
  • It is possible to view the earthquake activity in real time here, at Raspberry Shake website.

 

A lot of green stars and red dots in Fagradalsfjall mountain on Reykjanes peninsula. Time on map is 5. July 2023 at 16:25 UTC.
Heavy earthquake activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

All data now suggest that an eruption is going to happen. Where it is going to start erupting is impossible to know and it is not possible to know when it is going to start erupting.

I’ll try to post update when more is known about what is going on.

Update on Fagradalsfjall activity at 11:40 on 5. July 2023

This is a short update since this situation is changing quickly.

  • Largest earthquake recorded so far had a magnitude of Mw4,8 and was felt over a wide area.
  • Uncertainty level has been declared for Fagradalsfjall mountain area because of this earthquake activity and the risk of an eruption.
  • Current depth of the magma is now 3 to 6 km and is getting shallower by each hour.
  • Over 2000 earthquakes have been recorded at the writing of this article.

 

A lot of earthquakes in Fagradalsfjall mountain. Time on image is 11:30 on 5th july 2023.
Earthquake swarm activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

The only web camera that I know of at the moment and is showing Fagradalsfjall mountain is this one here. When the eruption starts, it should be visible in some part on this web camera. I hope that other closer web cameras are going online soon. Those where run by Rúv and mbl.is in last eruption.

Update on the activity in Fagradalsfjall mountain

This is a short update on the activity in Fagradalsfjall mountain.

Currently there have been around 200 earthquakes that have happened at the writing of this article. The first magnitude Mw3,1 took place at 22:45 UTC. This magnitude is automatic and is going to change when the earthquake is reviewed.

Green star and a lot of red dots in Fagradalsfjall mountain.
The heavy earthquake activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

There’s a lot going on at the writing of this article and the situation can change without warning. I’ll post updates as best I can.

Earthquake swarm in Fagradalsfjall mountain

Today (4. July 2023) there has been a earthquake swarm in Fagradalsfjall mountain. Largest earthquake had a magnitude of Mw1,6 and at the writing of this article there have not been any earthquakes with magnitude above Mw2,0. This might change without warning.

Red dots in Fagradalsfjall and yellow and blue dots in other places on Reykjanes peninsula.
Earthquake activity on Reykanes peninsula. Copyright of this image belongs to Icelandic Met Office.

Smaller earthquakes swarms sometimes seems to happen before an eruption in Fagradalsfjall mountain. The current earthquake swarm has all signs of dyke intrusion. If that is going to result in eruption now is impossible to know.