Swarm – Page 104 – Iceland geology

March 31, 2013

Deep earthquakes in Askja and Kverkfjöll volcanoes

This is a update for both Askja and Kverkfjöll volcanoes. Since they both had deep earthquakes today. None of this earthquakes where larger then magnitude 1.0. There depth was around 22 to 24 km inside the volcanoes them self.

Earthquakes in Kverkfjöll and Askja volcanoes. There depth was around 22 to 25 km. Copyright of this image belongs to Icelandic Meteorological Office.

GVP Kverkfjöll volcano profile. GVP Askja volcano profile.

It is impossible to know for sure what this means in terms of future activity. But this are both active volcanoes and should be treated as such.

March 29, 2013

Magnitude 3.5 earthquake south of Langjökull glacier

Today at 17:24 UTC a magnitude 3.5 earthquake took place south of Langjökull glacier. This earthquake had pre-earthquakes with the magnitudes from 2.1 and up 2.8. There where also several smaller earthquakes at the same location. This earthquake did appear clearly on my geophones in south and north Iceland. My webicorders can be viewed here.

Langjökull earthquake activity today. Copyright of this picture belongs to Icelandic Meteorological Office.

This appears to be normal tectonic earthquake swarm that are common for this area. They are not related to any volcano activity at present time. But this area often has earthquake activity with it being connected to any volcano activity. The earthquake swarm is continuing when this blog post is published. This earthquake swarm might stop at any time, or pick up at any time without a warning. If that happens. I am going to write a new blog post about it soon as possible.

March 29, 2013March 29, 2013

Magnitude 4.4 earthquake north of Kolbeinsey Island

Today at 17:32 UTC there was a magnitude 4.4 earthquake north of Kolbeinsey Island. I do not know if this earthquake was tectonic or volcanic in nature. I do know that there where several aftershocks following this earthquake. Since I did register them on my geophone in north Iceland. The geophone web site can be viewed here. More information about the earthquake can be found here, on EMSC web page.

Regional view of the area where the earthquake took place. Copyright of this image belongs to EMSC.

Icelandic Meteorological Office did also detected many of this earthquakes that took place there. But detection from this location is difficult due to distance from the SIL network.

The earthquake swarm location according to Icelandic Meteorological Office. Copyright of this image belongs to Icelandic Meteorological Office.

For now this is just a earthquake swarm and nothing else. Regardless of what happens later. Earthquake activity has been common in this area of the rift zone for several months now. I do not know why that is. The ocean depth in this area is around 3 to 4 km where it is the deepest. So if an eruption takes place there it is not going to be noticed due to the depth of the ocean.

March 26, 2013March 26, 2013

Deep earthquakes in Askja volcano

Today (26.03.2013) at 08:09 UTC there where three deep earthquakes in Askja volcano. The most depth of this earthquake swarm was 25.5 km. None of the earthquake had the magnitude above 2.5. The strongest earthquake had the magnitude 2.1 with the depth of 20.4 km

Earthquakes in Askja volcano. Askja is located to the north of Vatnajökull glacier and the lake is round in shape on this map. Marked by the orange dots on it. Copyright of this image belongs to Icelandic Meteorological Office.

This activity is part of an progress that started in Askja volcano back in the year 2010. So far this has not lead to any eruption. But it has created some odd changes. Along one was that Askja lake was ice free last year (winter 2012). The reasons for that are still not known to me.

Blog post updated at 16:32 UTC on 26.03.2013.

March 20, 2013

Earthquake swarm on the Reykjanes ridge

Today (20.03.2013) at 10:51 UTC an earthquake swarm started on the Reykjanes ridge. This earthquake swarm was about 850 km away from Reykjavík so it was not felt. This also gives little information on what is happening in this location. Since the depth of the ocean at this location is around 2 to 3 km. The largest earthquake in this swarm had the magnitude of 4.8 according to automatic EMSC results. The range of magnitude that was detected is from 4.6 to 4.8. The estimated depth is around 10 km. But that might not be correct.

The location of the strongest earthquake in this swarm on the Reykjanes ridge. Copyright of this image belongs to EMSC.

More information on the strongest earthquake in this swarm can be found here, on the EMSC web site. I do not know if activity is going to continue in this place. This location is just too remote to know that for sure.

March 17, 2013

Earthquake activity intensifies in Skjaldbreið

The earthquake activity that started in Skjaldbreið yesterday continues. This earthquake activity has been picking up in number of earthquakes. But when this blog post is written no earthquake has been over magnitude 2.0. That however might change if this earthquake activity picks up more from the current activity level.

Earthquake activity in Skjaldbreið south of Langjökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

It is hard to know what is going to happen in this earthquake swarm. But earthquake activity in this area is often “slow”, in the terms it is slow to start and reaching its high point. If that is going to happen now is impossible to know. All that can be done is to watch and see how this earthquake swarm progresses and if any stronger earthquakes start to appear. Stronger earthquakes might not appear at all in this earthquake swarm. But they also cannot be ruled out.

March 17, 2013March 17, 2013

Three earthquakes in Hekla volcano

During the night there where three earthquakes in Hekla volcano. All of the earthquakes where small with the magnitude of 0.6 up to 0.9. Depth of this earthquakes was on the range of 10.7 and down to 11.8 km. No other activity has followed this earthquakes in Hekla volcano since this earthquakes took place.

The earthquakes in Hekla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Currently there are no signs of volcano eruptions in Hekla volcano. If that changes I am going to write about it. But for now Hekla volcano is as quiet as it has been since the year 2000. When last eruption took place.

March 16, 2013

Minor earthquake swarm in Skjaldbreið

During the night a small earthquake swarm started in Skjaldbreið south of Langjökull glacier (might be part of Presthnjúkar volcano). This earthquake swarm is minor. With largest earthquake only being magnitude 1.9. While this is an minor earthquake swarm there seems to be more activity taking place then appears on reviewed and automatic SIL map. The reason for that is the earthquakes in questions are small to be located by three or more SIL stations in the area. While this unseen earthquake activity does not appear on Icelandic Meteorological Office maps it can be seen on the SIL station closest to the earthquake locations.

Location of the earthquake swarm in Skjaldbreið. Copyright of this image belongs to Icelandic Meteorological Office.

Activity at the end of this tremor plot suggests more earthquakes are taking place. But they are not being located as they are not detected on three or more SIL stations. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquake activity is common in this area. Since it is on the tectonic plate boundaries in Iceland. It is difficult to know how this earthquake swarm is going to behave in the next few hours. But so far it has stopped for few hours before continuing again.

March 10, 2013

Earthquake swarm in TFZ

During the night an earthquake swarm started in TFZ. The first earthquake had the magnitude of Mw3.8 according Icelandic Meteorological Office. This earthquake was felt clearly in the area it has been reported. Above 20 aftershocks have been recorded in this area following this earthquake.

Location of the magnitude 3.8 earthquake in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

Trace of the earthquake activity. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake was well detected on my geophone in north Iceland. This image is released under CC Licence. Please see CC Licence page for more details.

It is possible to watch this earthquake activity on my geophone network page here. At the moment the earthquake activity has stopped. It is impossible to know if it is going to start again in this area or not. But this area is normally highly active in terms of earthquake activity during the year. So earthquakes swarms like this are not uncommon.

March 3, 2013

Deep earthquake swarm in Tungafellsjökull volcano

Today (03.03.2013) between 13:19 UTC and to 13:21 UTC a deep earthquake swarm took place in a volcano named Tungnafellsjökull. This was a minor earthquake swarm, with the largest earthquake having magnitude 1.4. But it is the depth that is important here. The depth was most at 28 km, with the shallowest earthquake having the depth 18.7 km. This suggest magma intrusion into the volcano at depth. A pattern that was seen during the Eyjafjallajökull volcano eruption as an example.

For the past few months. Tungnafellsjökull volcano has been having swarms of earthquakes. All of them small, but many of them above 2.0 in magnitude. But so far none above magnitude 3.0. While earthquake activity has remained low in Tungnafellsjökull volcano I find that events are speeding up there in the past few months. With the terms that more earthquakes are being detected in this volcano and now at more depth. I find this worrying and also interesting. This volcano is far from any populated area, so any damage resulting for an eruption in it should be minimal. It also has no glacier to speak of. There is going to be a bad weather in Iceland until Friday (according to the weather forecast at the moment), so detecting any small earthquakes in this area might be limited by it.

The red dots show the earthquake activity in Tungnafellsjökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

It is too early to know what happens in Tungafellsjökull volcano. It is also important to note that Tungnafelljökull volcano has never erupted in historical times. This makes figuring out what happens next in it more difficult then ever. This activity might not mean an eruption is imminent. But at the moment I cannot rule one out just yet. It is clear that more activity is going to be needed before the picture of what is taking place in Tungnafellsjökull volcano gets clearer.

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