Category: Earthquakes

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Update on Sundhnúkagígar activity on 21. December 2023 at 18:47 UTC

This is a short article, written on 21. December 2023 at 18:47 UTC. Information here might go outdated quickly and without warning.

The eruption that started on 18. December 2023 at 22:17 UTC is over, best I can see. This was large eruption, but a short one. Total lava flow covered an area of 3,7 km2 (square kilometre). Most of the eruption happened in the first 24 – 48 hours of the eruption. There are early indicators that inflation has resumed in Svartsengi volcano, if it inflates at the same rate as before this eruption it is only going to take 8 to 10 days until next eruption. This is a big question since there’s a lot of magma in Svartsengi volcano and that magma can move towards the surface, even if the inflation doesn’t happen and can result in a larger eruption. If that happens is a wait and see situation.

Videos from the eruption areas show a lot of degaussing in the eruption fissure. This is interesting and I am not sure why that is. There’s a chance a lot of magma is in the dyke that is just releasing gas into the air without having the energy to erupt. There’s a small chance that a new eruption might happen in the same location. If that happens is impossible to know.

Red dots and yellow dots in the rift zone valley where the eruption just ended. Time on image is 21. Des. 2023 at 19:15 UTC.
Earthquake activity along the rift valley. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is interesting, it started yesterday (20. December 2023). This follows the same pattern as the earthquake activity before the start of the eruption on 18. December. If that is what is happening remains a wait and see situation for now.

This is the last update unless something happens in this area. Based on current information, that is what is going to happen, the question is just when.

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Update for Sundhnúkagígar eruption on 20. December 2023 at 18:29 UTC

This is a short update and information here might go outdated quickly and without warning.

This eruption is a short one and that’s how eruptions in Iceland are normally. This eruption might end by Friday to Monday, depending on what happens.

  • The flow from the craters that are erupting is around 10m3/sec. This is low compared to the start of the eruption on Monday 18. December 2023 and suggest that this eruption is going to end soon.
  • GPS data shows that Svartsengi volcano has only lowered around 80mm since Monday. This means there’s a lot of lava in Svartsengi for new eruptions to happen without much warning.
  • Earthquake activity along the fault valley has resumed, after stopping soon after the main eruption took place. This is interesting and I am unclear what this means at the writing of this article.
  • Icelandic Met Office is reporting that the eruption, even is small, is stable at the writing of this article. This can change without warning.
  • The lava field is now, according to best measurements around 3,7 km2 (square kilometres).
  • According to University of Iceland Earth science department, the chemical makeup of the lava shows that its more evolved in part than the lava in Fagradalsfjall volcano. This can be read here (new link, now in English). This means that this magma stopped on its way to the surface and cooled a little and changed chemical makeup before erupting.
  • This new lava is different than the lava that erupted 2400 years ago at the same location. Why that is I don’t know. It is going to take few years to maybe get an answer to this question when the experts have done their research and published their science papers.
Earthquake activity along the rift valley in Svartsengi volcano shown by a green stars, red and orange dots showing smaller earthquakes.
Earthquake activity along the rift valley. Copyright of this image belongs to Icelandic Met Office.

It is interesting to see that Þorbjörn mountain continues to get lower, based on GPS data from today (20. December 2023). Icelandic Met Office has released new danger map and that can be found here in English on Icelandic Met Office website.

This is all the information I know of today (20. December 2023). Next article should be tomorrow (21. December), unless something happens then I’ll try and write article soon as I can.

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Update on the eruption in Sundhnúkagígar on 19. December 2023 at 21:46 UTC

This is a short update and information here might go outdated quickly. This article is written on 19. December 2023 at 21:46 UTC.

I am trying to collect and read all the information I can find. I don’t have access to everything my self, so I am depended on news and reports from Icelandic Met Office and others on what is happening in this eruptions. This is not unusual and has always been like this.

  • The eruption is now in 2 to 4 vents. I am little unclear at the writing of this article now many are erupting.
  • The new dyke seems to go into the dyke from 10. November. This can result in reactivation of the dyke from 10. November and result in an eruption along it, all 15 km at random location.
  • Current flow seems be around 50m3/sec at the writing of this article. I’ve been hearing that highest flow yesterday (18. December) was around 800m3/sec, but that number is for me unconfirmed. It dropped to 100 – 500m3/sec soon after the eruption started.
  • Early GPS data from today seems to suggest that Svartsengi volcano has lowered about 50mm since the start of the eruption. I am waiting for new GPS data on Icelandic Met Office website. That data hopefully shows up tomorrow (20. December).

There’s a lot of uncertain things that can happen with this eruption at the moment. Since there’s a lot of lava in Svartsengi volcano that has not erupted so far. New inflow of lava from the deep mantle is also a possibility and those can happen without warning as the pressure drops in Svartsengi volcano sill (or magma chamber).

I’ll post next update tomorrow (20. December 2023) or sooner if anything happens.

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Update on the eruption in Sundhnúkagíga on 19. December 2023

This article is written on 19. December 2023 at 02:35 UTC. Information in this article can go outdated quickly and without warning.

  • The fissure is at last measurement around 4000 meters long (4 km) according to the news.
  • The volcano that is erupting is Svartsengi volcano. On some maps this is shown as Reykjanes volcano.
  • This is the largest eruption on the Reykjanes peninsula  so far.
  • The lava flow is mostly to the east, a way from infrastructure and roads. This is mostly, but can change without warning.
  • There’s a lot of gas pollution from this eruption. This gas is dangerous to people and animals.
  • The lava flow from the fissure is around 100m3/sec to 200m3/sec.
  • The fissure has started to form crates. This is going to continue to create craters as the eruption goes on.
  • There’s a ongoing risk that the eruption fissure might extend to the south towards Grindavík. If that actually happens is impossible to know.

I am going to write next update sometimes later today (19. December 2023) when I have new information and more is known about this eruption.

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Eruption started close to Hagafell mountain (Update for Grindavík on 18. December 2023 at 23:17 UTC)

This is a short update. Information here is going to get outdated quickly.

An earthquake swarm started at 21:05 UTC in the dyke area that formed on 10. November 2023. This earthquake swarm is ongoing and seems to be connected to when the eruption fissure expands south towards Grindavík town. The eruption started at 22:17 UTC. There’s a lot of dangerous gas pollution from this eruption. Do not get close to this eruption. This is not a small tourist friendly eruption.

A lot of red dots showing the earthquake activity in the dyke and Svartsengi just before the eruption.
The earthquake activity in the dyke. Copyright of this image belongs to Icelandic Met Office.

I’ll post new article when I know more in next few hours.

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Earthquake swarm in Tjörnes Fracture Zone

During the night and into the morning of 18. December 2023 an earthquake swarm took place in Tjörnes Fracture Zone just south east of Grímsey island. Largest earthquake in this swarm had a magnitude of Mw3,4 at 08:06 UTC and was felt in Húsavík, Akureyri and Grímsey according to the news. Other earthquakes in this swarm where smaller in magnitude.

Green star just south-east of Grímsey island. With few dots that show the area of the earthquake activity in the Tjörnes Fracture Zone.
Earthquake activity in Tjörnes Fracture Zone. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity in this area is common and larger earthquakes are frequent. Earthquake swarms happen regularly. This earthquake swarm seems to have ended.

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Inflation in Svartsengi volcano reaches 10. November levels

This information is unclear, but this is the best information I have at the writing of this article.

It seems that Svartsengi volcano has reached close or the same level as 10. November levels. There has been a slight shift where the inflation has been happening. It seems to have moved slight closer towards Þorbjörn mountain, that also means the main inflation is happening closer to Sundhnúkar and Sundhnúkargígar and Sýrlingafell mountain. This strongly suggest that magma is building up in this area because of the ongoing weakness in the crust in this area. This also strongly suggests that when the magma in this sill goes next on the move, it is going to go up towards Sundhnúkar and Sundhnúkagígar area and into the dyke that formed on 10. November 2023. That dyke has filled up all available space created by the rift valley, next dyke is more likely to start an eruption than the dyke created on 10. November.

There’s no earthquake activity in Svartsengi volcano at the moment, until that happen, the volcano is quiet at the writing of this article. It is more than likely that an strong earthquake swarm is going to start in Svartsengi volcano and close to Sundhnúkar and Sundhnúkagígar once the magma gets moving again. Inflation in a volcano does not always result in increased earthquake activity, since this depends slightly on what has been happening and how the crust is in that volcano at that time when activity is ongoing. It is impossible to know when next activity starts in Svartsengi volcano, but there is a chance that the magma that has flowed into the sill needs a time to change before it moves again. That can take time, how long is difficult to know, but this might be from six months and up to two years at most. This depends on the magma flowing in, gas content and such, so it can happen both slower and faster than earlier inflow of magma into the sill in Svartsengi volcano.

At the writing of this article. Everything is quiet in Svartsengi volcano.

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Earthquake swarm close to Eldeyjarboða on Reykjanes ridge

Today (9. December 2023) at 05:55 UTC to 06:44 UTC an earthquake swarm took place deep on the Reykjanes ridge. This earthquake swarm is far from the coast so smaller earthquakes where not detected by Icelandic Met Office. Largest earthquake in this swarm had a magnitude of Mw3,8.

Green star and yellow dots far from the coast of Reykjanes peninsula. This is far out in the ocean.
Earthquake activity deep on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

This is in a volcano, its unclear if this is in the volcano Eldeyjarboði or a different unnamed volcano. This earthquake swarm seems to have stopped by now.

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Earthquake swarm east of Grímsey island

Today (9. December 2023) an earthquake swarm took place east of Grímsey island, it started at 11:09 UTC and ended around 12:19 UTC. This was a small earthquake swarm and largest earthquake had a magnitude of Mw3,0.

Green star and red dots east of Grímsey island from the small earthquake swarm. This is out in the ocean.
Earthquake swarm east of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

This area of Tjörnes Fracture Zone has frequent earthquakes and earthquake swarm activity. Large earthquake swarms happen in this area every few years. Time between them is different. If that is the case now is impossible to know.

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Update for Grindavík on 8. December 2023

This is a short article about the situation in Grindavík. Information here might go outdated quickly without warning.

Sorry for the late update. I was updating my computer and its been more of a problem than I expected. Since I build my own computers, rather than buying already assembled computer.

Overview of the situation in Grindavík

Inflow into the dyke seems to have stopped one to two days ago. This means that it has started to cool down, since no inflow of fresh magma means it starts to form into rock. This is going to take years and in some areas decades cool all the way through. This also means that the rift valley is no longer moving as much as it was doing and in some areas has stopped completely. There is a crust instability in and around Grindavík town because of the rift valley, but this instability is now lower compared to first few days after 10. November. This might continue for years, even after all eruption activity stops few hundred years into the future.

Inflation has now reached almost the same level as 10. November, with only 50mm to go until the same level is reached. This inflation seems to be creating cracks in the ground around Svartsengi power plant. But the news was not clear on exact area of the formation of those cracks in the ground. Svartsengi, Grindavík and the area around the dyke continues to be a danger zone as defined by Icelandic Met Office.

This image shows the four danger zones around Grindavík. With zone 1 being in Svartsengi, Zone two to be north of Grindavík and zone three to be south east of Svartsengi and north of Grindavík. Zone four is Grindavík. Zone three is the most dangerous one.
The danger zones in Grindavík. Copyright of this image belongs to Icelandic Met Office.

The original image can be found here on Icelandic Met Office website.

This is not over and it is impossible to know when next sequence of events starts in Svartsengi and there is going to be little to no warning when it starts next. Icelandic Met Office has sad that at most there is going to be a two hour warning before an eruption starts, but it might even be shorter time. Making staying in Grindavík and nearby area all hours of the day a dangerous thing to do.

This is the last update until something happens in Grindavík.