Month: October 2021

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Long period, low frequency earthquake activity increases in Torfajökull volcano this morning

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 volcano system of Torfajökull volcano north of Mýrdalsfjökull glacier. With few dots in it showing few poorly located earthquakes.
The located earthquake activity in Torfajökull volcano. Copyright of this image belongs to Icelandic Met Office.

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.

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Earthquake activity east of Grímsey island

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.

Earthquake activity east of Grímsey island. Largest earthquake shown by a green star.
Earthquake activity east of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

Earthquakes are common in this area and large earthquake swarm happens in this location every 2 to 10 years.

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Earthquake activity west of Kleifarvatn lake

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.

Earthquake activity west of Kleifarvatn lake. Two green stars on top of each other show the strongest earthquakes.
The earthquake activity in Krýsuvík-Trölladyngja volcano system. Copyright of this image belongs to Icelandic Met Office.

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.

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Swarm of low frequency earthquakes in Torfafjallajökull volcano

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.

A image show earthquake activity in Torfajökull volcano as it appears on nearby SIL station. This is a plot with line showing every hour. The earthquake activity appears as thickness on the earthquake plot.
Earthquake activity in Torfajökull volcano. Copyright of this image belongs to Icelandic Met Office.
Harmonic tremor plot showing the earthquake activity in Torfajökull volcano since midnight as it appears on Slysaalda SIL station tremor plot.
Harmonic tremor activity showing the earthquake activity. Copyright of this image belongs to Icelandic Met Office.

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.

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Earthquake north of Hveragerði town

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.

Earthquake north of Hveragerði shown with a green star
Earthquake north of Hveragerði. Copyright of this image belongs to Icelandic Met Office.

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.

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Fewer earthquakes close to Keilir, no eruption in Fagradalsfjall mountain for almost one month

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.

Earthquake activity close to mountain Keilir marked by a green star close to it of the map on Reykjanes peninsula
Earthquake activity close to Keilir mountain on Reykjanes peninsula. Copyright of this image belongs 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.

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Earthquake swarm in Reykjanes volcano

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.

Two green stars out in the ocean shows the location of the earthquake swarm that was happening on Reykjanes ridge in the volcano of Reykjanes. Green star is also close to Keilir volcano that had an activity yesterday also.
Earthquake activity out in the ocean on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

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.

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Inflation and earthquake activity in Askja volcano

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).

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Ongoing earthquake swarm close to Keilir mountain

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.

Green stars on Reykjanes peninsula close to the mountain Keilir. Shows where the current activity is.
The earthquake activity close to Keilir mountain. Copyright of this image belongs to Icelandic Met Office.

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.