Category: Monitoring

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Earthquake swarm close to Geirfugladrangur island

On Monday 11. September 2023 an earthquake swarm took place close to Geirfugladrangur island out on the Reykjanes ridge. Largest earthquake had a magnitude of Mw3,4. Other large earthquake had magnitude of Mw3,2 and Mw3,0. Other earthquakes where smaller in magnitude, according to Icelandic Met Office, but this earthquake swarm has not been reviewed yet so magnitudes might change when that happens.

Green stars and yellow dots on Reykjanes ridge far from the coastline that shows the location of this earthquake swarm. Its in the more deeper areas of the Reykjanes ridge.
Earthquake swarm on the Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

Earthquakes in this earthquake swarm where not felt, because of distance from the coastline and populated areas.

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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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Inflation detected in Torfajökull volcano

Icelandic Met Office reported that inflation has been detected in Torfajökull volcano. This inflation started around middle of June. The inflation has now reached around 40mm.

Torfajökull volcano caldera. This image is purple to green from west to east. The centre of the Torfajökull caldera is shown with red colour to show the inflation.
The inflation of Torfajökull volcano. Copyright of this image belongs to Icelandic Met Office.

How fast this is going to evolve is difficult to know since last eruption took place in 1477 and that was probably an eruption as a result of magma injection from Bárðarbunga volcano. Last eruption in Torfajökull volcano it self might have happened last in the year 1170. Eruptions in Torfajökull volcano are almost always explosive eruptions with an dangerous ash cloud that drifts under the direction of wind.

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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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Increased hydrothermal activity in Askja volcano

This is a short article about Askja volcano. Because I am getting information that are in my view slightly conflicting with each other.

It seems that an there has been a increase in gas and hydrothermal activity in Askja volcano and in nearby area because of inflation that is currently taking place. At the writing of this article the inflation in Askja volcano seems to have reached between 80mm to 100mm. The reports have been slightly difficult to place in a good picture of what is happening. That’s why I am limiting coverage about this until it becomes more clear to me what is going on.

The general advice from Icelandic Met Office is that people should not hike around Askja volcano or nearby area because of risk of gas and sudden eruption. There is no special earthquake activity at the moment and that makes it difficult to know what is going on. This might change without warning, as is sometimes the case with volcanoes.