Category: Earthquakes

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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)

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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.

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Dyke intrusion into Fagradalsfjall volcano

Today (7. September 2023) an tyke intrusion took place in Fagradalsfjall volcano. The main depth of the dyke intrusion is at around 7 km depth. All earthquakes following this dyke intrusion where small in magnitude, from Mw0,1 in magnitude and up to Mw1,0 in magnitude. This seems to be a rather large dyke intrusion, since part of it does not create any earthquake activity at all because of earlier dyke intrusions at this depth in this part of Fagradalsfjall mountain.

Earthquake activity in Fagradalsfjall volcano shown here with orange dots because all earthquakes are small. A area of dots just east of Keilir mountain, showing more earthquake activity.
Earthquake activity in Fagradalsfjall volcano. Copyright of this image belongs to Icelandic Met Office.

Morgunblaðið (link below) is reporting that inflation has now reached 15mm in this area. This is really soon after the end of the eruption, since in last three eruptions, dyke intrusions and other early signs of activity that an eruption is about to happen starts around three to six months earlier before an eruption happens at the ten month time, as has been the case in the last three eruptions. It is possible that next eruption is going to happen earlier than last three eruptions. It is possible to know when next eruption is going to happen.

Icelandic News about this

Skjálftavirkni og vísbending um kvikusöfnun (mbl.is, Icelandic)

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Earthquake in Reykjanes volcano

Today (1. September 2023) at 17:55 UTC an earthquake with the magnitude of Mw3,1 took place in Reykjanes volcano. This earthquake was located out in the ocean and some distance from the coastline. I don’t think it was felt. Few other smaller earthquakes took place at the same location following the largest earthquake.

Green star and red dots out in the ocean not far from Reykjanestá area in the volcano Reykjanes. Time on picture is 01. Sep. 2023 at 19:40.
Earthquake activity in Reykjanes volcano. Copyright of this image belongs to Icelandic Met Office.

There is a storm now in this area of Iceland. That makes detection of smaller earthquakes impossible, along with distance from the coastline. If this earthquake swarm is going to be ongoing when the storm ends is impossible to know.

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Earthquake in Katla volcano

Yesterday (29. August 2023) at 23:49 an earthquake with magnitude of Mw3,7 took place in Katla volcano. This earthquake was felt on nearby camping sites and farms according to a news report. Few smaller earthquakes took place following the largest earthquake.

Green star in Katla volcano caldera along with few dots showing smaller earthquakes. The green star and orange dots are in the south part of the Katla volcano caldera.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

Nothing more happened following this earthquake, as has been the case for the last few earthquake swarms in Katla volcano. More earthquake activity can start in Katla volcano without warning.

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Dyke intrusion into Brennisteinsfjöll volcano

During the night of 26. August 2023 an dyke intrusion started in Brennisteinsfjöll volcano. This was in the form of many small earthquakes, most of them did not reach magnitude Mw1,0. What gives this away as an dyke intrusion is the fact the deepest earthquake in this swarm had a depth of 21,1 km. There was interestingly, a lot of surface earthquakes. I am not sure on why that is.

Yellow dots in Brennisteinsfjöll volcano the east of Fagradalsfjall volcano on Reykjanes peninsula. A lot of smaller earthquakes all over the Reykjanes peninsula on this map. Time on map is 26. August 2023 at 17:00 Icelandic time.
Earthquake activity in Brennisteinsfjöll volcano. Copyright of this image belongs to Icelandic Met Office.

There’s no risk of eruption at the moment from Brennisteinsfjöll volcano. Earthquake activity is too low and this process is clearly not far along now for an eruption too happen. That might change without much warning at some point.

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Strong earthquake swarm close to Geirfugladrangur on Reykjanes ridge

Yesterday (13. August 2023) an large earthquake swarm took place close to Geirfugladrangur (small rock island, population birds) on the Reykjanes ridge. The largest earthquake had a magnitude of Mw4,5 and was felt to Akranes town and possibly in other nearby towns on Reykjanes peninsula. There where not many reports about this earthquake being felt. Something above 400 earthquakes took place during the most active phase of this earthquake swarm.

A lot of green stars on Reykjanes ridge, a little off the coast of Iceland. Along with a lot of yellow dots showing the age of the earthquakes. A lot of dots showing earthquakes in other areas on the Reykjanes peninsula.
Earthquake activity on the Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm seems to be ongoing. It is at the moment, at much slower rate than before. There are clues that suggest this might have been a earthquake activity connected to magma movements in this area. Its difficult to be sure, because this area is under the ocean and measuring what is going on gets more difficult as future away from land activity happens. Eruption at this distance is going to appear on the Icelandic Met Office SIL network.

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Earthquake activity in Hofsjökull volcano

Yesterday (12. August 2023) an small earthquake swarm took place in Hofsjökull volcano. Largest earthquake had a magnitude of Mw3,0 and the second largest earthquake had a magnitude of Mw2,5. The area is remote and there are no reports of this earthquakes being felt.

Dots in Hofsjökull volcano, that is at the center of this image. Between Langjökull to the west and Vatnajökull to the south-east. One earthquake is located at the caldera rim in the south part of Hofsjökull volcano. Other earthquakes are located on a line in north part of the volcano.
Earthquake activity in Hofsjökull volcano. Copyright of this image belongs to Icelandic Met Office.

According to Morgunblaðið news there where report of smelling gas after this earthquake activity. There is a risk of gas pockets around Hofsjökull volcano, probably mostly to the north in the area closest to the earthquake area.

I don’t have any other information about Hofsjökull volcano. Because it last erupted more than 12.000 years ago. At most there might have been smaller eruptions that resulted in lava flows sometimes in the last 12.000 years. I don’t expect an eruption now, this earthquake activity might signal a long term change in Hofsjökull volcano. How long that is going to be is anyone guess. It might be in the next 100 to 500 years or maybe never. Hofsjökull volcano is on its own rift zone that is slowly dying off. Along with Kerlingafjöll volcano to the south of Hofsjökull volcano. This are the only two (?) active volcanoes on this old dying rift zone (its around 5 to 10 million years old).

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Earthquake swarm in Torfajökull volcano

Today (30. July 2023) an earthquake swarm took place in Torfajökull volcano. This volcano is located north of Katla volcano (Mýrdalsjökull glacier). This area has had regular earthquake swarms over the year. Why is not clear. There is no clear signal of magma movement in this area. Torfajökull erupts highly Felsic magma that’s mostly explosive and some type of magma that can flow as a lava flow (maybe in later stage of an eruption, I don’t know for sure).

Green star north of Katla volcano (Mýrdalsjökull glacier) and in Torfajökull volcano caldera rim to the north. Time on map is 30. July 2023 at 19:40 (Iceland time)
Earthquake activity in Torfajökull volcano. Copyright of this image belongs to Icelandic Met Office.

The largest earthquake in this swarm had a magnitude of Mw3,2. It was felt in nearby tourist areas and caused few rock slides. Icelandic Met Office is still warning against rock slides because of this earthquakes close to the earthquake swarm location. There is a ongoing risk of more stronger earthquakes in this area of the volcano at the writing of this article.

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Two strong earthquakes in Bárðarbunga volcano

Yesterday (28. July 2023) at 23:42 UTC and 23:55 UTC two earthquakes with magnitude of Mw3,2 and Mw3,6 took place in Bárðarbunga volcano. EMSC is reporting the earthquake at 23:55 as Mw4,7 and that information can be found here.

Two green stars in Bárðarbunga volcano in Vatnajökull glacier. Time on map is 29. july 2023 at 13:05 (UTC).
Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

There where few smaller earthquakes following this larger earthquakes. This is normal inflation activity in Bárðarbunga volcano and this is going to continue for next 30 to 70 years (based on earlier history).