Increased hydrothermal activity between Keilir mountain and Trölladyngja mountain

Rúv News is reporting today (10. September 2023) that there has been noticeable increase in hydrothermal activity east of Keilir mountain since end of least eruption close to Litli-Hrútur mountain. According to the news, this shows that magma is now close to the surface without erupting currently. This area is rather large, it is between Keilir mountain and Trölladyngja mountain (part of Krýsuvík-Trölladyngja volcano). There have been reports of increased SO2 vents that is killing moss in this area, along with new steam vents that have been appearing in the last few weeks.

According to Þorvaldur Þórðarson volcanologist, there is a magma shadow in the area around Trölladyngja and that appeared around the time the eruption close to Litli-Hrútur started. This area was noticed by Thomas Fisher earthquake expert from Czech Republic did notice this area having almost no earthquakes at all. Showing that magma has pushed it self into the crust at this location at shallow depth.

The result of this is that next eruption might have more eruption vents, it might erupt at more than one fissure at the same time in parallel. What happens next is unclear, but this large area has gotten really warm and seems to be continuing to expand.

Rúv news

Fylgjast vel með auknum jarðhita austan við Keili (Rúv.is, has map of the area)

Earthquake swarm in Krýsuvík-Trölladyngja volcano

During the night of 9. September 2023 an earthquake swarm started at 03:24 UTC with a magnitude Mw3,8 earthquake. This earthquake was felt in Reykjavík area and other nearby areas.

Green star and red dots in Krýsuvík-Trölladyngja volcano on the Reykjanes peninsula. There are also many other dots over the Reykjanes peninsula showing earthquake activity in other volcanoes.
Green star in Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met office.

Its unclear if this earthquake swarm is ongoing. There is a lot of earthquake activity in this area because of inflation in Fagradalsfjall volcano.

Stress related earthquake in Krýsuvík-Trölladyngja volcano system

Today (8. July 2023) at 17:57 UTC an earthquake with magnitude of Mw4,5 took place in Krýsuvík-Trölladyngja volcano system. This is a stress realted earthquake because of the inflation between Keilir and Fagradalsfjall mountain.

Difficult to see in all the activity, on the right there is a green star and a lot of red dots below it. That is where the earthquake took place. There's a lot of activity on this map because of Fagradalfjall mountain.
The earthquake activity in Krýsuvík is on the right on this map. A green star with a lot of red dots under it. Copyright of this image belongs to Icelandic Met Office.

More of this earthquakes are going to happen both east and west of the dyke between Keilir and Fagradalsfjall mountains. Both before an eruption and after it ends. This type of earthquakes can have magnitude above Mw5,0 and they can happen in areas that have been quiet so far.

Magma detected deep under Reykjanes peninsula

According to a news on Rúv News there has been detection of magma at considerable depth on Reykjanes peninsula. This magma is actively trying to reach the surface, but has not been successful for now. This has resulted in a lot of dyke intrusions on the Reykjanes peninsula in recent months. Earthquake activity seems to follow each inflation period on the Reykjanes peninsula according to the news.

The magma in the deep crust and in the mantle is going to increase in volume until it can break up the surface. How long that is going to take is something I don’t know. Next eruption cycle is going to start with a large earthquake, just like the last one. Based on all current data that I have.

Rúv news in Icelandic

Jarðskjálftavirkni aukist síðustu daga og vikur (Rúv.is)

Earthquake swarm in Krýsuvík-Trölladyngja volcano (Kleifarvatn lake)

Today (28. June 2023) an earthquake swarm took place in Krýsuvík-Trölladyngja volcano in Kleifarvatn lake. Largest earthquake had a magnitude of Mw3,2 at 09:21 UTC and was felt in Reykjavík area and other nearby towns.

Green star and red dots in Kleifarvatn lake in Krýsuvík-Trölladyngja volcano. There are red dots and orange dots in nearby Fagradalsfjall volcano.
Earthquake activity in Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met Office.

Its unclear what is going on at this location. Most likely explanation for this activity is stress changes because of inflation in nearby Fagradalsfjall volcano. At the moment, I don’t think there is going to be an eruption in Krýsuvík-Trölladyngja volcano. This earthquake swarm looks like its ongoing at the writing of this article.

Earthquake in Kleifarvatn lake in Krýsuvík volcano

Today (30. May 2023) an earthquake took place in Krýsuvík volcano in Kleifarvatn lake. This earthquake had a magnitude of Mw3,1. I don’t know if this earthquake was felt, it is possible. This earthquake is the second earthquake in this magnitude range in last few days.

Green star in Kleifarvatn lake. Along with few other blue dots on Reykjanes peninsula showing earthquake activity in other volcanoes. One red dot in Reykjanes volcano just west of Grindavík town.
Earthquake activity in Keifarvatn lake. Copyright of this image belongs to Icelandic Met Office.

This seems to be normal earthquake activity, it doesn’t seems to be connected to any magma movement in Krýsuvík volcano. Effects of inflation in other volcanoes (Fagradalsfjall volcano) is something that might be starting to create earthquakes. This is difficult to see in the data at the moment, but that might change in next few weeks if that is happening.

Earthquake swarm in Krýsuvík-Trölladyngja volcano

Yesterday an earthquake swarm started in Krýsuvík-Trölladyngja volcano. This earthquake swarm doesn’t appear (it might be connected, but it is difficult to know currently) to be connected to the inflation that is happening at Fagradalsfjall volcano. Largest earthquake in this earthquake swarm had a magnitude of Mw3,0. This earthquake swarm took place just south-west of Kleifarvatn lake.

Green star just south-west of Kleifarvatn lake in Krýsuvík volcano. Where few smaller earthquakes have been taking place in a small location in Krýsuvík volcano.
Earthquake activity in Krýsuvík volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm doesn’t seems to indicate an magma movement. There has not been any indicators (clear) that Krýsuvík-Trölladyngja volcano has gone active. It remains a dormant volcano.

Earthquake swarm in Krýsuvík-Trölladyngja volcano

Today (21. December 2022) an earthquake with magnitude of Mw3,4 took place in Krýsuvík-Trölladyngja volcano. This earthquake is because of inflation in Fagradalsfjall volcano. This possibly means that the inflation in Fagradalsfjall volcano is reaching critical point and might result in a eruption soon, when that point is reached is difficult to know.
Continue reading “Earthquake swarm in Krýsuvík-Trölladyngja volcano”

Magnitude Mw3,5 earthquake in Krýsuvík-Trölladyngja volcano

Today (12-October-2022) at 14:18 UTC an earthquake with magnitude of Mw3,5 took place in Krýsuvík-Trölladyngja volcano. This earthquake was followed by few smaller aftershocks. This earthquake seems to be happening because of a inflation that is taking place in Fagradalsfjall volcano and this strongly suggests that inflation in Fagradalsfjall volcano is slowly reaching critical levels. There is no eruption expected from Krýsuvík-Trölladyngja volcano as is.

Green star with few red dots just west of Kleifarvatn lake, showing increase in activity in Krýsuvík-Trölladyngja volcano
Earthquake activity in Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity suggests that more stronger earthquake activity is possibly on the way. When it might start is difficult to know for sure. This has been the pattern in recent months. Earthquake activity starts to appears like this and then one day a major earthquake swarm starts. What happens now is a wait and see as before.

Inflation from start of September in Krýsuvík-Trölladyngja volcano and in Reykjanes volcano

According to GPS data from Icelandi Met Office that can be viewed here for Krýsuvík-Trölladyngja volcano (Þorbjörn) and here for Reykjanes volcano. It seems that a inflation period, at least in Krýsuvík-Trölladyngja volcano started in early September and is ongoing at the writing of this article. Earthquake activity is low at the moment, but the area has already moved a lot in recent earthquake swarms and that might he dropped the crustal stress in the area. It might also explain some of the GPS movements. I have some, but limited understanding of reading GPS data so my assessment might be off, wrong or both.

There also seems to be inflation going on, without many earthquakes in Reykjanes volcano. That seems to be have been going on since start of August. There have not been any eruption in Reykjanes volcano even after repeated inflation and deflation cycles in the volcano. Inflation cycles often have earthquake swarm activity if dyke activity follows an inflation event. That does not seem have happened this time around.

If this inflation continues, in either one or both volcanoes. It is clear a new period of high earthquake activity is about to start on Reykjanes peninsula. When that earthquake activity is going to start is impossible to know. Since recent earthquake and volcano activity has changed how the crust works in the parts of the Reykjanes peninsula where magma has been active. Since hot magma slowly softens the hard rock in the crust at depth and that lowers the earthquake activity. Rather then at the start of an volcano activity, when the crust is cold and brittle, resulting in high earthquake activity before an eruption.

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