Earthquakes – Page 125 – Iceland geology

March 21, 2013

Two earthquakes on Reykjanes ridge

During the night and last night (20.03.2013) there where two earthquakes on the Reykjanes ridge. Location of this earthquakes is not the same and several hundreds of km between them. So they are in fact not connected at all. This is just by chance this activity takes place at the same time. As often is the case in this type of area.

The first earthquake was an magnitude 5.4 earthquake deep on the Reykjanes ridge. This earthquake was on 10 km, or at least that is the best estimate by EMSC. The distance from Reykjavík is about 1100 km. More information on this earthquake can be found here on EMSC web site.

The magnitude 5.4 earthquake deep on the Reykjanes ridge. Copyright of this image belongs to EMSC.

The second earthquake was an magnitude 4.3 earthquake, with the default depth of 10 km according to GFZ. It had the distance about 850 km from Reykjavík. More information on this earthquake can be found here on EMSC web site.

The magnitude 4.3 earthquake on the Reykjanes ridge. Copyright of this image belongs to EMSC.

It is impossible as before to know what is happening on at this location. Due to the depth of the ocean at this place and how remote this location is.

March 21, 2013

New earthquake in Hekla volcano

This morning there was an earthquake in Hekla volcano at 08:23 UTC. This earthquake had the magnitude of 1.4 according to the reviewed data from Icelandic Meteorological Office. The depth of this earthquake was 11,2 km. But that is considerable depth for this location. This is most likely not tectonic earthquakes. But it is hard to be sure on that detail as of this moment.

The earthquake in Hekla volcano is marked by an orange dot on this map. Copyright of this image belongs to Icelandic Meteorological Office.

I do not have a clue what Hekla volcano is up to at the moment. But this is highly unusual activity for this volcano. Since normally there are no earthquakes in Hekla volcano until just before an eruption takes place in it. For the moment. The only thing that can be done now is to monitor what is taking place in Hekla volcano.

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 20, 2013

Magnitude 4.8 earthquake deep on the Reykjanes Ridge

During the night there was an earthquake deep on the Reykjanes ridge. This earthquake had the magnitude of 4.8 according to automatic result from EMSC.

The earthquake on the Reykjanes ridge. Copyright of this image belongs to EMSC.

Due to earthquakes location there is not a lot of details on it. But this location on the Reykjanes ridge has been seeing some activity in the past few months. This might well just be normal tectonic activity for this area. More information on this earthquake can be found here.

March 18, 2013

Earthquake activity in Esjufjöll volcano

Earthquake activity has started again in Esjufjöll volcano after some time with no activity. The two earthquakes that where detected by the SIL network only had the magnitude of 1.0 and 1.1. But what is most interesting is there depth. But registered depth is around 0.1 km (around 100 meters). This really shallow depth for earthquakes in this location. While it is unclear what is creating this earthquake activity. The most likely reason is that an minor dike intrusion is taking place in the volcano. Last eruption in Esjufjöll volcano is believed to have taken place in the year 1920. But that has not been properly confirmed yet.

Earthquake activity in Esjufjöll volcano is marked by the red dots in Vatnajökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

It is impossible to know for sure what is happening in Esjufjöll volcano. Not only is there little known about earlier eruption history of this volcano. It has also been poorly studied in the past. So what to expect if anything happens is not known properly. Based on earlier earthquake activity in this volcano from the year 2011 more earthquakes might happen in next few days to months. But it is impossible to know that for sure at the moment. But it is not an bad idea to monitor this volcano for any more activity in next few weeks.

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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