Strong earthquake activity in Fagradalsfjall mountain, Krýsuvík-Trölladyngja volcano

This information is going to get outdated quickly.

There is now a constant earthquake swarm activity in Fagradalsfjall mountain, part of the Krýsuvík-Trölladyngja volcano system. More than a dozen of earthquakes have been larger than magnitude 4,0 and it doesn’t look like this earthquake activity is doing to stop soon. Largest earthquakes in last few hours had a magnitude of Mw4,8 and Mw4,5. The earthquake north of Grindavík town appears to be a tension breaking earthquakes because of magma inflation in Fagradalsfjall mountain.

A lot of earthquakes on Reykjanes peninsula, more than a dozen green stars, hundres of red dots showing smaller earthquakes
The earthquake activity on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.
Heavy earthquake activity shown on Icelandic Met Office earthquake tracker. The density of earthquake activity has the image swamped with activity
Earthquake activity on Reykjanes peninsula in Fagradalsfjall mountain for the last 48 hours. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm is close to Grindavík town, this is a similar situation that happened earlier in the year 2021. Just before the eruption in Fagradalsfjall mountain. This earthquake activity is going to continue to grow until an eruption starts. This earthquake activity also happens in a wave, resulting in it lower earthquake activity between powerful earthquake activity. I am expecting more strong earthquakes in next few days, unless an eruption starts in Fagradalsfjall mountain or nearby area.

Update on activity in Krýsuvík-Trölladyngja volcano in Fagradalsfjall mountain, eruption is going to happen soon

Information here are going to get outdated quickly.

The earthquake activity in Fagradalsfjall mountain continued on 22-December and on 23-December-2021. Largest earthquake in last few hours had a magnitude of Mw4,9 and was felt over a wide area. No property damage has yet happened because of this earthquake activity so far.
There are now three centres where the earthquake activity is happening. The first one is north of the large crater, the second one is under the main crater and the third one is in Nátthagakrika (about south-west of the large crater). This is the area where people used to walk up the eruption on walking paths A and B.

Dense earthquake activity on Reykjanes pensiula with lot of earthquakes and green stars and red dots
The heavy earthquake activity on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.
Plot showing the magnitudes of the earthquake and density. A lot of earthquake that go above 3 line and dense dots with smaller magnitudes
The density of the earthquake activity in the current earthquake swarm. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is not going to stop until an eruption starts. When that happens is not possible to know. If a new crater opens up that is going to result in ever growing and stronger earthquakes. If the crater that is already in place starts erupting again, that is going to result in some earthquake activity. What is known is that the magma is going to go the path of least resistance, whatever that path might be. At the writing of this article, over 6000 earthquakes have been recorded and around 50 to 100 of them have been larger than magnitude 3,0.

Earthquake swarm in Krýsuvík-Trölladyngja volcano, close to Fagradalsfjall mountain, eruption possible soon

This information is going to get outdated soon. Since the situation is changing quickly.

It is possible that a new eruption is about to start in Fagradalsfjall mountain in Krýsuvík-Trölladyngja volcano. This earthquake activity started around 17:00 UTC on 21-December-2021 and has been growing since then. At the writing of this article the largest earthquake had a magnitude of Mw3,3. Over 150 earthquakes have been recorded at the writing of this article. This earthquake activity doesn’t seems to be slowing down.

Earthquake activity in Fagradalsfjall, a lot of red dots, green star shows the largest earthquake
Earthquake activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

The situation is changing quickly. As of writing this article a new eruption has not yet started but that might only be question of hours until an eruption starts. This might happen during the night or sometimes tomorrow during the day. There is not any way to know that for sure at the writing of this article.

I’ll post update late tomorrow if this changes and a eruption starts. Since I’ll be busy during the day the late article can’t be helped.

Continued aftershock activity south of Hekla volcano

Today (21-December-2021) at 09:37 UTC an earthquake with magnitude of Mw3,0 took place south of Hekla volcano.

Green star south of Hekla volcano showing the magnitdue 3,0 earthquake
Earthquake activity south of Hekla volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is an aftershock activity of the Mw5,2 earthquake that happened about one month ago. This earthquake activity is possibly going to continue for months.

Earthquake swarm in Vatnafjöll mountain (south of Hekla volcano)

Today (13-December-2021) at 16:04 UTC an earthquake swarm started in Vatnafjöll mountains. This looks like a aftershock activity from the Mw5,2 earthquake in this area few weeks back. Three earthquakes with magnitude above Mw3,0 took place. The earthquake magnitudes where Mw3,0 (at 16:04), magnitude Mw3,2 (at 16:07) and magnitude Mw3,5 (at 16:08).

Græn stjarna suður af Heklu sýnir staðsetningu jarðskjálftanna í Vatnafjöllum mountains
Earthquake activity south of Hekla volcano in Vatnafjöll mountains. Copyright of this image belongs to Icelandic Met Office.

There continues to be a risk of more aftershocks in this area. It remains a question if there is going to be a stronger earthquake activity in this area in next few weeks.

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Earthquake swarm north of Grindavík town

Today (8-December-2021) an earthquake swarm started north of Grindavík town. Largest earthquake in this swarm so far had a magnitude of Mw3,1 at 10:44. The news doesn’t say if this earthquake was felt in Grindavík. Earthquake activity has been going up recent weeks since the eruption in Fagradalsfjall ended on 18th September 2021. A swarm of smaller earthquake activity is currently ongoing in this same area at the writing of this article.
Continue reading “Earthquake swarm north of Grindavík town”

Sharp change in harmonic tremor in Grímsfjall volcano

This situation is unclear and nothing has been confirmed as of writing of this article. This seems to have started about 1 hour ago and there has been a change in the harmonic tremor levels at Grímsfjall volcano. This is not yet the super sharp change I did see in May-2011 when that eruption happened. This is however is possibly a change in harmonic tremor that is consistent with magma moving inside the volcano system. Earthquake activity has been minimal in the last 24 hours.

Harmonic tremor on blue, green and purple harmoniuc tremor bands going up sharply in the last one hour.
Harmonic tremor changes in Grímsfjall volcano in the last one hour (article written at 17:34 UTC on 04-December-2021). Copyright of this image belongs to Icelandic Met Office.

This is a monitoring situation currently. Sometimes an eruption happens after a glacier flood or doing a glacier flood in Grímsfjall volcano. At other times however nothing happens and it is not possible to know what happens now.

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