Category: Iceland

Posted on

Growing earthquake swarm in Krísuvík volcano

There seems to be a growing earthquake swarm in Krísuvík volcano on the Reykjanes peninsula. The strongest earthquake so far is a ML2.2 according to the automatic size estimate. Some ghost earthquakes appear to be outside a town called Akranes and Reykjavík to the north. But that are earthquakes that are in fact nothing but errors. This earthquake swarm is tectonic in nature, not volcanic. So there is not going to be a eruption in Krísuvík volcano from what I can tell at current moment.


The earthquake swarm in Krísuvík volcano. Copyright of this picture belongs to Iceland Met Office.

It is hard to know how this earthquake swarm is going to develop. But this earthquake swarm looks growing. For that it is going to peak in activity sometimes in the next few hours. But when exactly is hard to know for sure. I am going to update this blog post if something major happens. The strongest earthquakes appears on my geophone and can be viewed here.

Posted on

Earthquake swarm 14 km to the east of Akureyri town

At 19:22 UTC a small earthquake swarm started 14 km east of Akureyri town. The earthquake swarm started with a earthquake with the size of ML3.11 at the depth of 9 km. The area of activity is unusual, but there are none known fault lines in this area that I am aware of. This area is also a bit off TFZ fault zone. This area normally does not have any earthquakes. I am not sure yet if this are intra-plate earthquakes or not, as this area is close to the NVZ (North Volcanic Zone).

This earthquake was felt in Akureyri town by the local people. How well I do not know.


The area where the earthquake swarm is taking place. Copyright of this picture belongs to Iceland Met Office.

I did record the strongest earthquake on enough geophone to be able to make a plot map from my own software from software called WinQuake that I use to plot earthquakes time, location and depth information with data from Iceland Meteorological Office.


Here is the earthquake location according to my geophones with location data from IMO. This picture is released under Creative Commons licence. See top bar for more information.

Here are the wave form data that where recorded on my geophones (they can be viewed online here). The Sauðárkrókur geophone is a testing geophone that I am currently running. But it is going to be turned off now in December.


The earthquake as it was recorded on the Heklubyggð geophone. This picture is released under Creative Commons licence. See top bar for more information.


The earthquake on Hvammstangi geophone. This picture is released under Creative Commons licence. See top bar for more information.


The test geophone at Sauðárkrókur village. This geophone is noisy. This picture is released under Creative Commons licence. See top bar for more information.


The strongest aftershock that I did record on my Hvammstangi geophone. The wave form data on Sauðárkrókur geophone where not good for some reason. So I do not display them here. This picture is released under Creative Commons licence. See top bar for more information.

The wave form outside the earthquake are ocean waves. They are strong now and show clearly on my geophone. So they appear even more clearly on the SIL network as higher tremor levels. But that is nothing that looks like a volcanic harmonic tremor.

As for the earthquake swarm. It is hard to know what it means. But more aftershocks in this area for the next few days are not impossible. As has been seen before in areas that suddenly start to make earthquakes after a long break.

Icelandic News reports of this event. Please use Google Translate with care. It does not yet understand.

Jarðskjálfti við Akureyri (mbl.is)
Jarðskjálftar við Akureyri (Rúv.is)
Þrír jarðskjálftar nærri Akureyri (Vísir.is)

Blog post updated at 06:02 UTC on 3 December, 2011. Fixing errors in the text.

Posted on

Activity remains low in Iceland. Eruption continues in El Hierro volcano

At the present time the earthquake activity remains low in Iceland. This goes for both Katla volcano and other areas of Iceland. This is the regular quiet time in Iceland, as it happens sometimes. For the next days, there is a risk of frost-quakes as the ground freezes over in a cold snap.

El Hierro volcano, Canary Islands

The eruption in El Hierro volcano continues as before. New eruption vents have been opening up at random in the south part of El Hierro volcano. Earthquake activity to the north has dropped. While at the same time, the earthquake activity seems to have increased slightly to the west part of El Hierro volcano. I am not sure why that is yet.

In the tremor data. I have been seeing several explosions taking place. But they create a spikes in the tremor plot, that is different then what happens when a earthquake takes place.


The current harmonic tremor from El Hierro volcano. Explosions are the spike activity (30 November, 2011). Some of this however might be sudden increase in eruption activity. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

Other then that. The eruption in El Hierro volcano seems to be about the same for the moment as it has been for the past almost two months now. So far it is impossible to know when this eruptions ends. But eruption in La Palma volcano lasted about one month on average. Eruptions in Lanzarote volcano have lasted about three months (last eruption was in the year 1824). Based on this. This might be a eruption that lasts for about 3 to 5 months at the longest in my opinion. But what actually happens is just something that is a wait and see matter.

Posted on

Update on the weekend activity

Iceland

This weekend was quiet in Iceland. There was almost nothing going on. There was only one small earthquake swarm in Krýsuvík volcano. But this earthquake swarm was tectonic in nature, not volcanic. The largest earthquake in this earthquake swarm was about ML3.2 in size. Few earthquakes where in Katla volcano, but less this weekend then many others. But it is normal for Katla volcano to be quiet during November to March each year due to snow that is added to the glacier. But that increased the pressure of the glacier on top of the magma chamber (floating balance laws at work here).

Mainland Spain

There was a flurry of earthquakes on Mainland Spain during the weekend. None of this earthquakes where felt, from what I can gather at IGN web site.

Canary Islands, Spain

The eruption at El Hierro volcano continues as it has done for the past almost two months now. The harmonic levels are about the same as it has been, but there seems to be minor intermittent in activity from El Hierro volcano. IGN has setup a picture web site with images that show the activity since this eruption started clearly.

Erik at Eruption blog has good blog post about the magma mixing that appears to be taking place in the eruption in El Hierro volcano.

Other then this. Is is all quiet in Iceland for the moment. But frost-quakes should be expected in the next 48 hours or so in Iceland. As the ground freezes over in a really cold weather.

Posted on

Bogus news story going around about Katla volcano

There is a bogus news story about Katla volcano. The bogus news are that Katla volcano is just few days from erupting. This is wrong. At the moment there are no signs that Katla volcano is about to erupt. There is currently a relative quiet in Katla volcano, compared to the activity several weeks ago. But that activity started after the minor eruption in Katla volcano in July 2011 (this summer). This bogus news is also annoying the staff at Iceland Met Office, how are now getting phone calls about this news. Where other professionals are trying to get more information on this or just trying to figure out if the news is correct or not.

For the moment, it is all quiet in Katla volcano. If there are any changes. I am sure to write about it here with up to date information on what is going on. While the Yellow Press is looking for big-foot or something. So once again, the yellow press has it wrong and spreads minor panic following this poor news reporting.

News about this in Icelandic.

Nágrannaþjóðir óttast Kötlugos á næstu dögum (DV.is, Icelandic)
Norskir miðlar: Óttast flóðbylgju í kjölfar Kötlugoss – Getur gosið hvenær sem er – Kötlu illt í maganum (Pressan.is, Icelandic, Picture from the 1918 eruption in this news)

Posted on

Earthquake swarm in Grímsey Island (TFZ)

Today there has been a earthquake swarm in Grímsey Island. But this tiny Island is off the north coast of Iceland. Around 100 people live on the Grímsey Island. This earthquake swarm is small. But its location makes sure that it is felt. But it is directly under the village on the Grímsey Island. So far the strongest earthquake recorded is a ML3.3 in size with the depth of 9.1 km.


The earthquake swarm in Grímsey Island. The Island is located where the earthquake swarm is on this map. Copyright of this picture belongs to Iceland Met Office.

The largest earthquake so far was recorded on my Hvammstangi geophone clearly.


The earthquake as recorded on my Hvammstangi geophone. This trace is filtered at 4Hz. This picture is released under Creative Commons licence. See top bar for more information.

The earthquake swarm appears to be ongoing. I am sure that this earthquake swarm is felt in the village because it is directly under it. But depth of the earthquakes might however play a role in it how well the earthquakes are felt in the village. So far there have not been any news reports on this earthquake swarm in Icelandic Media.

Blog post updated at 00:25 UTC on 25 November, 2011

Posted on

Rare earthquake close to Hvammstangi geophone

A rare earthquake took place yesterday close to my geophone in Hvammstangi village. But that village is located in north-west Iceland. This earthquake was small and I do not have location at moment, as I only have one geophone at this location for recording earthquakes.What I do know about this earthquake was around 25 km away from my geophone, with the default depth at 10 km. But this distance is a bit inaccurate due to default depth factors. So this is just a best effort guess. But what I do have is the wave form of this earthquake.


The vertical (Z) component of the earthquake. This picture is released under Creative Commons Licence. Please see the top bar for more information.


The North-South component of the earthquake. This picture is released under Creative Commons Licence. Please see the top bar for more information.


The East-West component of the earthquake. This picture is released under Creative Commons Licence. Please see the top bar for more information.

All the pictures here above show the 20 seconds wave form signal of the earthquake. I have marked the P and S wave of the earthquake in order to figure out the distance this earthquake took place from my geophone.

In this area I get around one to two earthquakes a year that are local and do not appear on the Iceland Met Office earthquake list. But that happens because there are few to none SIL seismometers in this area and IMO can only detect earthquakes that are larger then ML1.5 to 2.5 in size.

If I get a location on this earthquake, I am going to update this blog post.

Posted on

The weekend earthquake swarm deep out on the Reykjanes Ridge

During the weekend there was as earthquake swarm deep outside on the Reykjanes Ridge. It was about 700 km south of Reykjavík city. It was not felt on land and was only noticed on instruments. The last earthquake to be recorded was at 22:04 UTC, on 20 November 2011. It’s size was Mb4.4 according to EMSC. The largest earthquakes in this earthquake swarm had the size of Mb4.8, but there where several earthquakes recorded with this size.

Due to the location it is impossible to know if there was a eruption in this area or not. The ocean depth there is greater then 1 km (if my memory is correct). This means that if a eruption is taking place in this location. Nothing is going to appear on the surface of the ocean. So why this earthquakes are taking place are only speculation everything besides normal tectonic activity in this area. But the Reykjanes Ridge is a rift zone that often has earthquakes without any eruption taking place. There have however been several earthquake swarm during the year in this location. But what the actual reason remains a mystery due the location.

Other then this it is now quiet time in Iceland. This is the type of quiet time that I always worry about. But lets wait and see what is up with this lack of activity in Iceland.

Note: Update on the eruption in El Hierro volcano eruption is due tomorrow. This is now a long term eruption as explained few blog posts ago. So there are only updates on what is going on once in a while.

Posted on

Katla volcano newest earthquake swarm

During the night of the 16th of November, 2011 there was a new earthquake swarm in Katla volcano. This earthquake swarm is a part of ongoing pattern in Katla volcano. This pattern started after the small eruption that took place in Katla in July 2011. It was observed yesterday that there was a deep earthquake in Katla volcano, with the depth of 28 km. This earthquake did most likely did happen due to a dike intrusion deep inside Katla volcano, but it might well be that this was just a normal earthquake. It is hard to know that for sure. But deep dike intrusions are well known in Katla volcano. Sometimes they are followed by a harmonic tremor for few moments or minutes.


The earthquakes from Katla volcano can clearly be seen on this tremor plot from Iceland Met Office. But they make the spikes that are on it. Copyright of this picture belongs to Iceland Met Office.


The location of last earthquake swarm in Katla volcano. Most of the earthquakes are inside the caldera of Katla volcano. Copyright of this picture belongs to Iceland Met Office.


The largest earthquake in this earthquake swarm. Its size was ML2.35 and it had the depth of 4 km. This picture is released under Creative Commons Licence. Please see the top bar (there is a link there) for more information on this.

This was a long period earthquake. But this is the only clue at the moment that Katla volcano is going to erupt soon. But when is still a unknown question at present time.


The frequency analysis of the ML2.35 earthquake. As can be seen here this earthquake has really low frequency component. But most of the energy goes into about 2Hz frequency. This picture is released under Creative Commons Licence. Please see the top bar (there is a link there) for more information on this.

It is impossible to know how many earthquake swarm Katla volcano is going to have before it erupts. But this is a one way street that Katla volcano is now on. For us humans, we just have to wait and see what happens next. Nothing else can be done when it comes to forces of nature. When the time comes, get out of the way of Katla volcano.

Posted on

Quiet time in Iceland in earthquake and volcano activity

Currently there is a quiet time taking place in Iceland. This does happen often in Iceland. Sometimes the quiet days are due to bad weather. But now the quiet seems to be a ongoing and has been for past few weeks. The exeption from that is the earthquake activity in Katla volcano and the man made earthquake activity in Hengill volcano. But that activity has dropped down for some reason the past few weeks. I am not sure why that is.

I also want to point people to a new feature on Iceland Metrological Office web site, that seems to have gone up only few days ago. But this web site shows the drumplot (webicorders) from the SIL network. This is not far from what my geophone network shows. That web site can be viwed here.

Blog post updated at 16:43 UTC.