Volcano and earthquake activity in Iceland
Yesterday (28-October-2021) an earthquake swarm took place east of Grímsey island. The largest earthquake had a magnitude of Mw3,9 at 22:06 UTC. It is not know if it was felt in Grímsey island.
Earthquakes are common in this area and large earthquake swarm happens in this location every 2 to 10 years.
Yesterday (28-October-2021) two earthquakes with magnitude of Mw3,6 and Mw3,0 took place west of Kleifarvatn lake (in Krýsuvík-Trölladyngja volcano system). The first earthquake with magnitude of Mw3,6 took place at 18:36 UTC and the second earthquake with magnitude of Mw3,0 took place at 23:11 UTC. Other earthquakes that took place where smaller in magnitude.
This earthquake activity seems to be connected to magma movements in the area. It has not yet and might not result in a eruption since this is in a different fissure area. It is unlikely that this activity is connected to the magma movements that are ongoing close to Fagradalsfjall mountain.
According to an announcement made by Icelandic Met Office there has been a swarm of low frequency earthquakes in Torfajökull volcano since midnight of 28-October-2021. The earthquakes don’t appear clearly on the Icelandic Met Office map but they can be seen on nearby SIL stations. According to Icelandic Met Office the rate of earthquake activity is about 1 – 2 earthquake every 15 minutes.
There are two things that can create this type of low frequency activity. The first one is water that has been superheated in the crust. The second option is that magma is now moving in Torfajökull volcano. This type of activity has happened before without any eruption happening. I think that is going to be the same now at the writing of this article. Since this is an active volcano the situation can change quickly and without warning.
There are no web cameras in the area that I know of. It is remote and there is almost no mobile coverage at this location. If there is a mobile connection, it is limited to 2G (GSM) or slow 3G connection.
At 01:28 UTC on 27-October-2021 an earthquake with magnitude of Mw3,3 took place 4 km north of Hveragerði town. This earthquake was clearly felt in Hveragerði and nearby area. No damage has been reported because of this earthquake according to earliest news.
There is a chance there is going to be more earthquake activity in this area. But few earthquakes with no more activity is also common in SISZ.
Earthquake activity continues close to Keilir mountain. But it remains at depth of 5 to 6 km and doesn’t show any sign that it is about to move to the surface. More than 10000 earthquakes have been recorded and 18 earthquakes have been recorded with magnitude above Mw3,0. This is according to Icelandic Met Office.
The eruption in Fagradalsfjall mountain (more information at Krýsuvík-Trölladyngja website at Global Volcanism Program) has not been active since 19-September-2021 and there are no signs that the eruption is about to restart soon. Global Volcanism Program no longer updates its information for this volcano as an active eruption. Icelandic scientists in eruptions have not declared the eruption over. It should be expected that the eruption in Fagradalsfjall mountain is over for now, but it can start again at the same location or at new location in few weeks time or maybe even few years from now.
Yesterday (12-October-2021) an earthquake swarm took place in Reykjanes volcano. Largest earthquake in this swarm had a magnitude of Mw3,3 and the earthquake swarm was out in the ocean not far from the coastline.
It is impossible to know for sure if this earthquake activity is directly connected to magma movements in this area. It is possible, but there have been some sign of magma moving in the crust in this area. The magma is moving but is not erupting or starting an eruption. Earthquake activity seems to be growing in this area of Reykjanes peninsula and Reykjanes ridge after the eruption in Fagradalsfjall mountain stopped.
Inflation has been increasing in Askja volcano over the last few weeks. According to latest news that inflation is now at 14 cm, since the inflation was detected at the end of August. On Saturday 9-October-2021 an earthquake with magnitude of Mw3,2 was detected in Askja volcano (I’ll try and add the picture later if I remember). This is was the strongest earthquake in Askja volcano in the last 20 years according to the news.
Askja is remote and there are no or limited amounts of web cameras in the area. With winter arriving going there is impossible for most people. If an eruption happens this winter the best view is probably going to be harmonic tremor data until pictures appears from Icelandic Met Office or someone with an air plane (if the weather allows for that).
The earthquake swarm with Keilir mountain continues today (2-October-2021) and largest earthquake at the writing of this article had a magnitude of Mw4,2. This might change without warning.
Based on what I am seeing it is my view that magma is the reason why this earthquake activity is happening. The magma seems trapped, based on the earthquake activity and that is interesting. This suggest that the feeder channel, that possibly started at this location has closed up and that is the reason why the eruption in Fagradalsfjall mountain stopped. At least that is the working idea, if it is true I don’t know.
Department of Civil Protection and Emergency Management and Icelandic Met Office has warned people against going to Keilir mountain because of risk of volcano eruption or large earthquakes.
It is unclear at the writing of this article if there are changes to hydrothermal activity close to Keilir mountain. There have been reports about it, but they remain unconfirmed at the writing of this article.
There is now a risk of an earthquake with magnitude of Mw6,0 in the area of Keilir mountain. The earthquake activity shows a pattern of high and low activity every few hours. Why this happens is not well understood at the writing of this article.
On Saturday 25-September-2021 an earthquake swarm started close to Keilir mountain, at the writing of this article this earthquake swarm is ongoing.
The eruption in Fagradalsfjall mountain has been having its longest quiet period since 19-March-2021 and at the writing of this article that is ongoing situation.
This earthquake activity suggest that the eruption time period in this part of the Reykjanes peninsula is not over, even if nothing is happening at the moment.
Krýsuvík-Trölladyngja is a volcano system is currently erupting in this area.
Article updated on 29-September-2021 at 11:49 UTC. Correct date of the earthquake swarm start added to the article.
Yesterday (15-September-2021) around 11:10 UTC a large lava cave just south of the crater in Geldingadalir had a roof collapse in a small area or a lava breakup in the surface. This resulted in the lava flow down Geldingadalir into Nátthagi. The flow covered Geldingadalir in less than 20 minutes. After that it did reach the barrier that stops it from going into Nátthagakriki, if that happens both walking path A and B are going to get closed forever or having to be redrawn from their current locations. Lava down that path also allows the lava flow to go in the direction of Grindavík town and nearby roads.
The lava flow yesterday did go down into Nátthagi but didn’t get far into there compared with the older lava it was flowing on top of. This sudden lava flow did put people in danger and shows that the lava field is full of dangerous caves that can collapse or burst open at any time without any warning. The lava flow that started yesterday is ongoing best to my knowledge. But the view has been limited due to fog and bad weather in Fagradalsfjall mountain this evening.
One or two idiots where seen walking on the crater rim yesterday and I think this are the same people that Icelandic coast guard had to transport from Gónhóll since they where unable to get back because of the new lava flow that had happened when they where there.
The crater is now ~334 meters above sea level high. Currently the crater is now growing in height but that can change without warning.
Pictures of this new lava flow are on social media. I can’t use them because of copyright but if searched they can be found and viewed. There are also some amount of videos of this lava flow on YouTube.
Fagradalsfjall mountain is part of Krýsuvík-Trölladyngja volcano system.
Added 10-January-2022
This article can be found in Spanish here.