Early signs of next eruption phase in Fagradalsfjall volcano

Since end of February 2023 there have been slowly growing signs in form of a small earthquake activity in Fagradalsfjall volcano and nearby area. It is impossible to know when next eruption starts in Fagradalsfjall volcano, but last time the quiet time was around 10 months. If it is going to be shorter or longer now is impossible to know.

Red dots and orange dots, not many of them in Fagradalsfjall volcano, in Krýsuvík-Trölladyngja volcano east of Fagradalsfjall and orange and blue dots west of Fagradalsfjall volcano in the volcano Reykjanes.
Earthquake activity in Fagradalsfjall volcano. Copyright of this image belongs to Icelandic Met Office.

Currently the earthquake activity is minor, but that can change quickly and without much warning. At the writing of this article, its been 6 months and 24 days since the eruption in Meradalir valley ended. I don’t know if this is going to happen the same was as it did before last eruption. Since there’s a lot of magma at depth of 5 to 10 km now and that changes how everything functions and behaves in the crust.

Eruption expected in Fagradalsfjall volcano this year (2023) or next year (2024)

It was reported in Rúv News that eruption is expected to happen in Fagradalsfjall volcano this year (2023) or next year (2024). When those eruptions happen is impossible to know. But before any eruption there’s going to be a large earthquake swarm as happened before the eruption in March 2021 and in August 2022. Fagradalsfjall volcano before the eruption in March 2021 had not erupted for 6000 to 8000 years. That means it unclear how the volcano is going to behave and its going to take a while until that is figured out, but for now it is probable that Fagradalsfjall volcano is going to work in similar way how Krafla volcano erupted between the year 1975 and 1984. With the difference that eruptions in Fagradalsfjall volcano are possibly going to last longer, based on data from other volcanoes on Reykjanes peninsula. This might go on for the next 10 to 20 years, with eruptions and quiet time period between them. Currently Fagradalsfjall volcano is in a quiet time.

This does not rule out eruptions in Reykjanes volcano (west of Fagradalsfjall volcano) and Krýsuvík-Trölladyngja volcano (east of Fagradalsfjall volcano) in next few years. Neither of those volcanoes have erupted in 700 to 900 years and at the writing of this article, don’t show any clear signs that they are about to erupt. Reykjanes volcano has had a lot of dyke intrusion activity since 2019, but no eruptions so far. Krýsuvík-Trölladyngja volcano has not had any dyke intrusion activity. Volcanoes east of Krýsuvík-Trölladyngja volcano, Brennisteinsfjöll volcano and Hengill volcano are currently quiet, but that might change without warning if magma starts to find path up those volcanoes.

Strong earthquake swarm in Reykjanes volcano on Reykjanes ridge / Reykjanes peninsula

This earthquake swarm is ongoing at the writing of this article and information can change without warning. The largest earthquake recorded by automatic magnitude of Mw3,7 at the writing of this article. Around 30 to 40 earthquakes have happened so far, but that number might change quickly. This earthquake activity has some signs that it might be happening because of magma intrusion in the area, out in the ocean but signals are not clear.

Three green stars and red dots on the left down side on the map of Reykjanes peninsula, the earthquake activity is happening out in the ocean on the Reykjanes ridge.
The current earthquake activity on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is in the volcano Reykjanes, that volcano goes into the ocean and is on dry land. Making possible future eruptions both explosive and flowing magma at the same time. To date, Reykjanes volcano only has had earthquake swarms and no eruption. When that is going to change is impossible to know.

Earthquake swarm 3 km north of Grindavík town

Today (19. December 2022) and yesterday (18. December 2022) an earthquake swarm took place 3 km north of Grindavík town in the Reykjanes volcano. Largest earthquake had a magnitude of Mw2,9 and was felt in Grindavík. Earthquakes with magnitude Mw2,0 are felt in Grindavík, possibly even smaller earthquakes. At the writing of this article, this earthquake swarm is ongoing but weather is blocking almost all of the automatic earthquake detection.
Continue reading “Earthquake swarm 3 km north of Grindavík town”

Earthquake swarm in Reykjanes volcano (3-December-2022)

Today (03-December-2022) at 12:49 UTC an earthquake with magnitude of Mw3,5 at 7,0 km depth. This was the largest earthquake in the swarm. Around of 40 earthquakes took place at the writing of this article. There are no reports about the largest earthquake was felt in nearby populated areas.

Green star on the left down corner of the image with orange dots showing smaller earthquakes. With few red dots in the same area.
Earthquake activity in the Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity suggest that a new inflation period is about to start in this part of the Reykjanes peninsula and Reykjanes ridge. There has been rather quiet time in Fagradalsfjall volcano and Reykjanes volcano since August when last eruption took place in Fagradalsfjall volcano. Reykjanes volcano has not erupted so far, but has continued activity of magma injection into the crust. When that is going to result in a eruption is impossible to know.

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.

Earthquake activity has started to increase in Fagradalsfjall and Reykjanes volcanoes

Since yesterday (06-October-2022) the earthquake activity has been increasing in the volcanoes Fagradalsfjall and Reykjanes volcanoes. Please note that Global Volcanism Program has updated the informations regarding Fagradalsfjall mountain and now classifies it as its own volcano, this is after a new report and information from Icelandic Met Office. From now on I am going to use that classification when updating on activity in Fagradalsfjall volcano. I’ll not update older articles (too much work), but this also applies to them as such.

This also means that Fagradalsfjall is a new volcano in Iceland.

Earthquake activity in Fagradalsfjall volcano, Krýsuvík-Trölladyngja and Reykjanes volcano. Shown with red, orange and blue dots
Earthquake activity in Fagradalsfjall volcano and Reykjanes volcano along with Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity at start of an eruption cycle in Fagraldsfjall volcano are not large. They grow larger once magma has started to push into the crust, until then the earthquake activity only seems to happens with minor earthquake swarms.

Article updated with new information.

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