Volcano and earthquake activity in Iceland
The earthquake today (11-November-2021) at 13:21 UTC with the magnitude of Mw5,2 seems to align it self with faults that are part of SISZ rather than being part of Hekla volcano system. The high frequency tone on 2 – 4Hz that I did see on few nearby SIL stations has started to lower again after the main earthquake. Earthquake activity in the area is currently dropping but it might increase again without warning.
Continue reading “Update on the Mw5,2 earthquake south of Hekla volcano”
At 07:20 UTC today (6-November-2021) an earthquake with magnitude of Mw4,0 took place in Bárðarbunga volcano. A swarm of smaller earthquakes happened in the same area before and after the strongest earthquake.
This earthquake activity shows that Bárðarbunga volcano continues to inflate after the eruption in 2014 to 2015. This does not indicate that an eruption is about to happen. A lot more earthquake activity and time has to happen before an new eruption happens in Bárðarbunga volcano.
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Around 10:00 UTC this morning (31-October-2021) the earthquake activity of long period and low frequency earthquakes increased this morning in Torfajökull volcano. The current swarm now seems to be coming from the glacier part of the caldera, the earlier activity seems to have taken part some place in north part of the Torfajökull volcano caldera. Location of the this earthquake activity is difficult if not impossible because of the type of earthquake activity being generated in Torfajökull volcano.
The situation is difficult to figure out just by looking at seismometer data. Icelandic Met Office is going to make a flyover today with the help of Icelandic Coast guard and try and see what is going on in Torfajökull volcano. Last eruption in Torfajökull volcano was in the year 1477 and I don’t have any idea what happens before an eruption in this volcano.
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.
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.