Category: Swarm

Posted on

Earthquake swarm in Katla volcano today (24.06.2012)

Earthquake swarm started in Katla volcano at 13:33 UTC. This earthquake swarm lasted until 14:26 UTC (24 June, 2012). Most of the earthquakes in this swarm where small. Less them magnitude ML1.0 in size. The largest earthquakes did have magnitude of ML1.3 and ML2.0. No harmonic tremor did take place during this earthquake swarm. However, harmonic tremor data from IMO suggests a lot of hydro-thermal activity under Mýrdalsjökull glacier. This might result in small glacier floods coming from Mýrdalsjökull glacier in hours to days time. There is also a good chance that new earthquake swarm starts in Katla volcano at any time. Since there has been pattern of repeated earthquakes swarms in Katla volcano for several weeks now.


Earthquake activity in Katla volcano today. The newest earthquake also appears on this image. Copyright of this image belongs to Iceland Meteorological Office.


The harmonic tremor level at Álftagrof SIL station. This is normal background movement. There are however clues that hydro-thermal activity might have increased under Mýrdalsjökull glacier following this earthquake swarms. Copyright of this image belongs to Iceland Meteorological Office.


Harmonic tremor at Slysaalda SIL station. This is normal background noise. Spikes are earthquakes in Katla volcano. In this image there are also minor clues about increased hydro-thermal activity in Katla volcano. Copyright of this image belongs to Iceland Meteorological Office.


The earthquake at 13:45 UTC on Skeiðflöt geophone. This trace is filtered at 1Hz. This image is released under Creative Common Licence. See CC Licence page for more details.


The earthquake at 13:45 UTC on Heklubyggð geophone. This is filtered at 1Hz. This image is released under Creative Common Licence. See CC Licence page for more details.

It is hard to know for sure what happens next in Katla volcano. But I am sure this activity is currently taking place is going to continue. This does however not say anything about possibility of an eruption in Katla volcano. That possibility remains unclear, as earthquake activity does not mean that an eruption is imminent. For the moment, there are just earthquake swarms taking place in Katla volcano. But that can change without warning. Until then less speculation on what is taking place in Katla volcano is best (in the news media anyway).

Blog post updated at 08:34 UTC on 25.06.2012.

Posted on

Earthquake swarm in Katla volcano, Kolbeinsey ridge, Hveravellir geothermal area

It has been a bit busy day earthquake wise in Iceland. But there has been more activity today then in past few weeks in Iceland. But it has been really quiet for a long time now in Iceland. But let’s start with the largest earthquake of the day.

Kolbeinsey Ridge

Today at 11:11 UTC there was an earthquake with the magnitude of ML3.65. This earthquake was not felt since it was more then 100 km away from nearest human population in Iceland. The earthquake took place on Kolbeinsey Ridge. It last erupted in the year 1755. No known eruption is known in this area since then. My geophone network did record this earthquake properly. The signal was strongest at my Hvammstangi geophone station. But it was also recorded on my Heklubyggð geophone station. On other geophone stations. The signal was too weak to be properly detected by my geophone.


The ML3.65 magnitude earthquake as it was recorded on my Hvammstangi geophone. This image is released under Creative Commons licence. Please see the CC Licence page for more details.


The ML3.65 magnitude earthquake as it was recorded on my Heklubyggð geophone. It is filtered at 1Hz. This image is released under Creative Commons licence. Please see the CC Licence page for more details.


The location of the earthquake. Copyright of this picture belongs to Iceland Meteorological Office.

Hveravellir geothermal area

There is an earthquake swarm ongoing (or it might be over. I have no good way to know that currently) at Hveravellir geothermal area. I only know there is an earthquake swarm there because of the tremor recording on Hveravellir geothermal area. But only two earthquakes have been large enough to appear on earthquake map on IMO web page.


The two earthquakes that did appear on IMO earthquake map. Copyright of this picture belongs to Iceland Meteorological Office.


However, Hveravellir SIL station did show that more was going on then did appear on the earthquake map. Most of this earthquakes are too small to appear automatic on the earthquake list. Some might even be too weak to be properly located by the SIL network. Copyright of this picture belongs to Iceland Meteorological Office.


Some of this activity did also appear on Skrokkalda SIL station I think. Copyright of this picture belongs to Iceland Meteorological Office.

Katla volcano

Katla volcano did have an new earthquake swarm during the night. This earthquake swarm had around 30 or so earthquakes. Most of them where located almost in the central caldrea. This type of swarm activity has now been ongoing since end of April, when it started rather sharply with an earthquake swarm. Since then it has had many earthquake swarm. But the current rate of earthquake swarm is around 1 to 3 earthquake swarm pr. Week. Normally they are in an new area inside the Katla volcano caldera.

My geophone station at Skeiðflöt records most of the earthquakes if the background noise is not too high during that time.


The earthquake activity in Katla volcano last night. Copyright of this picture belongs to Iceland Meteorological Office.

So far. This is just normal earthquake activity. It does not signal any chance of eruption activity so far. But this earthquake pattern is interesting. What it means is a different matter. So far, nobody knows for sure at this point in time. This activity seems to change hydrothermal activity inside Katla volcano caldera. This has also created minor glacier floods from Katla volcano caldera. But the flood have been seen on instruments that record water conditions in Múlakvíls glacier river. Glacier floods are marked by higher conductivity of the water, darker color and stronger sulfur smell (rotten egg smell). What happens next in Katla volcano is anyone guess. As Katla volcano has proven to be unpredictable volcano.

Posted on

Minor earthquake swarm in Katla volcano

Today (28.05.2012) at 11:22 UTC an small earthquake swarm did start in Katla volcano. This earthquake swarm did end at 12:28 UTC. This is small earthquake swarm, both in numbers of earthquakes and in the magnitude of the earthquakes in the swarm. With the largest earthquake having the magnitude of ML1.4. The depth of this earthquake swarm was around 0.1 km, but that gives the depth around 100 meters or so. Following this earthquake there has been some minor disturbance at Álftagróf SIL station. But because it only appears on one SIL station. This change might have its origin in something else. Like human traffic, local wind etc. For the moment I cannot rule that out.


The change in tremor at Álftagróf SIL station. This change in tremor might not be because of Katla volcano. But something else. Please keep that in mind. Copyright of this picture belongs to Iceland Meteorological Office.

If the tremor changes at Álftagróf SIL station where from Katla volcano. They where highly local and did not show up on other SIL stations for some unknown reason. That has happened before, but the SIL network was not as dense around Katla volcano back then.


Image of the active area in Katla volcano. Copyright of this picture belongs to Iceland Meteorological Office.

I find it most likely reason for this earthquake swarm where some changes in hydrothermal areas inside Katla volcano caldera. All hydrotheraml areas in Katla volcano are under high pressure due to the glacier that is on top of them. So changes might not happen without some earthquake activity as did happen few hours ago. This is also not in any way a sign that Katla volcano might be about to erupt. This is far too low earthquake activity for such event to be starting. There is an chance of small glacier flood following this earthquake swarm in next 8 to 24 hours. But it is far from certain that is going to happen.

Posted on

Earthquake activity in Herðubreið is not volcanic in nature

The earthquake activity in Herðubreið during past few days is not volcanic in nature, or magnetic in nature. It is purely tectonic in nature. But the faults that have been moving are vertical, not horizontal as so many earthquake faults. Earthquakes are common in this area, as it on the eastern rift zone. The fault lines in this area of Iceland are highly active at times. Iceland Metorlogical Office has released this interesting information about the earthquake activity in this area during the past few years.


The first fault plane in Herðubreið. This one has the direction of N41°A. Copyright of this image belongs to Iceland Meteorological Office.


The second fault plane in Herðubreið. This second fault has the direction of N221°A (49°). Copyright of this image belongs to Iceland Meteorological Office.

Most of the earthquakes are on the depth of 5 to 6 km according to IMO.


The earthquake activity in Herðubreið the days 14 to 17 of May 2012. Copyright of this image belongs to Iceland Meteorological Office.


Earthquake activity in Herðubreið during the years 2005 to 2006. Copyright of this image belongs to Iceland Meteorological Office.


Total amount of earthquakes in Herðubreið from the years 2005 to 2012. This clearly shows that activity in this area has been rather constant during this period. Copyright of this image belongs to Iceland Meteorological Office.

The area in question is outside Askja volcano main fissure swarm. It is also outside Kverkjföll volcano main fissure swarm. So this earthquakes are tectonic in nature. But even so this area has erupted in the past. But for now. It is just earthquakes and not magma on the move, or breaking its path up to the surface as was case in Upptyppingar tuff mountain. The images are from Week 20 overview (what is up about it) at IMO web site.

Posted on

Earthquake swarm continues close to Herðubreið. Earthquake activity in Katla volcano

The earthquake swarm that started in Herðubreið two days ago continues. So far over 100 earthquakes have been recorded. Most of them are less then ML2.0 in magnitude. But this earthquake swarm continues at slow rate. This is not a big earthquake swarm. Based on number (in my system) of earthquakes pr hour. But in my system, a large earthquake swarm has tens to hundreds of earthquakes pr hour.


The earthquake swarm in Herðubreið. Copyright of this image belongs to Iceland Meteorological Office.


A bit higher resolution of the earthquake swarm in Herðubreið. Copyright of this image belongs to Iceland Meteorological Office.

Katla volcano

There is some earthquake activity in Katla volcano. But it is not high. There was one small earthquake this evening (it did appear on my Skeiðflöt geophone). But it has not been reviewed. So both size and depth are going to change.


Earthquake activity in Katla volcano during the past few days and until today. Copyright of this image belongs to Iceland Meteorological Office.

The earthquake activity in Katla volcano is also showing interesting pattern during this week (Week 20). It seems that earthquake activity is focusing on one point inside the caldera. It is hard to know for sure what this means at current time. But it is my opinion that it is not a good sign. But so far, nothing major has been happening inside Katla volcano caldera at this time. Until that happens, it is just best to keep watch and keep speculations within the amount of what is going on.


Earthquake activity in Katla volcano during Week 20 (current week). Copyright of this image belongs to Iceland Meteorological Office.

Beside this activity. It has been quiet in Iceland now for several weeks now. That is not un-common to happen during some years. While other years are often more active, some years are quiet. It is not clear yet if the year 2012 is going to be quiet year in Iceland or not.

Posted on

Earthquakes in Katla volcano. Earthquake swarm continues close to Herðubreið. Other earthquake activity

This morning there was a short earthquake swarm in Katla volcano caldera. This earthquake looks like a minor dike intrusion did take place this morning. Current series of events did start on 28. April 2012. With a small earthquake event and a small glacier flood that did follow it. Along with harmonic tremors coming from the glacier flood and possibly Katla volcano caldera (hydro-thermal activity boiling or something of that nature). I do not yet know if there was any glacier flood following the event this morning. But so far there is nothing that suggests a small glacier flood did take place following the earthquake swarm this morning.

The earthquake swarm this morning took place on an location that did erupt on 8 and 9th of July 2011. So it is clear the area that erupted last year is picking up activity again. But there was an drop in activity from end of November 2011 until end of April 2012.


Earthquake activity in Katla volcano this morning. Copyright of this picture belongs to Icelandic Meteorological Office.

This earthquake activity did appear well on my geophone at Skeiðflöt farm.


Earthquake activity in Katla volcano caldera this morning on my Skeiðflöt geophone. There is a lot of noise on this geophone. But earthquake activity can still be seen on this. The earthquakes are marked by red (some noise is also marked by red). This picture is released under Creative Commons Licence. See CC Licence page for more details.

It is clear that Katla volcano seems to be warming up to an eruption. But it is impossible to know when such eruption might happen, or how big it is going to be.

Herðubreið

Earthquake activity continues south-west of Herðubreið. But almost all of the earthquakes have been less then ML2.0 in magnitude. Earthquake activity has been slowing down all day. At the moment, it appears this earthquake swarm is close to being over.


The earthquake activity close to Herðubreið mountain. Copyright of this picture belongs to Icelandic Meteorological Office.

This area is well known for for earthquake activity. So this is not something that is new in this area.

Reykjanes Ridge

According to EMSC and USGS there have been several earthquakes with the magnitude of Mb4.5 to Mb4.8 on the Reykjanes Ridge. Earthquake activity is common on the Reykjanes Ridge. But because of the location and depth (around 2km) it is impossible to know if there any volcano eruption taking place at this location. It might well be, or not.

Kolbeinsey Island

Over the past weeks there has been some earthquake activity close to or in Kolbeinsey Island. The largest earthquakes have had the magnitude around ML3.0, with some underestimates due to distance from the SIL network. At this moment it is impossible to know if this earthquake activity is related to possible eruption activity. But it believed that an eruption (or dike intrusion) took place on Kolbeinsey Ridge in the year 1999. It started off with a large earthquake swarm.

Posted on

Minor earthquake activity in Iceland

During the past few weeks it has been quiet in Iceland. Really quiet, with almost nothing going on. It is still like that to some extent. So this is just a short overview of the small activity that has been taking place in Iceland during the past 48 hours or so.


The earthquake activity in Iceland during the past 48 hours. Copyright of this image belongs to Iceland Met Office.

The most activity in the last 48 hours have been on the Reykjanes and on TFZ. But there was an small earthquake swarm in each area. With earthquakes that did not get over ML2.5 in size so far. Two earthquakes where in Askja volcano. One in Grímsfjall volcano fissure system (maybe in Þórðarhyrna volcano).


Earthquake west of Hekla volcano, in the SISZ. This picture is released under Creative Common Licencee. See the licence page for more detail.

Katla volcano

During this winter. Katla volcano has been quiet. This is somewhat normal, as more snow means more ice-mass on top of the volcano. But now that has started to melt a little and that means less ice-mass on top of the volcano. That could mean more activity in Katla volcnao during the next few weeks. So far however the activity remains small and there are no special earthquakes to report.


Earthquake activity in Katla volcano, on this picture earthquake activity west of Hekla volcano can also been seen here. Copyright of this image belongs to Iceland Met Office.

The earthquakes west of Hekla volcano belong to the SISZ fault area. Not Hekla volcano it self. What is also interesting is the earthquake activity in south part of Katla volcano. In area outside of the glacier. This are small earthquakes, that do not appear on my geophone. Even if they are close to it. I am unsure what this means for the future. But it is worth keeping an eye on it.

Posted on

Strong earthquake in Mexico, early size is estimated at Mw7.6 (EMSC)

At 18:02 UTC there was an earthquake with the size of Mw7.6, it had the depth of 20 km according to EMSC. This size estimate is based on early data and is a subject to a change.


Regional view of the earthquake according to EMSC. This might change as the earthquake data is reviewed by EMSC and USGS. Copyright of this picture belongs to EMSC.


Local view of this earthquake according to EMSC. This might change as EMSC reviewed by EMSC and USGS. Copyright of this picture belongs to EMSC.

This earthquake was detected by my geophones. Currently I am unable to publish those traces as my earthquake computer is still offline as I have not yet moved to Denmark. This earthquake also appears clearly on IMO SIL network.

I am going to update this blog post as the information changes.

Posted on

Continued earthquake activity in El Hierro volcano

While the eruption in El Hierro volcano ended some time ago, there has been an constant earthquake activity ongoing in El Hierro volcano. While this earthquake activity has not been in high volume at the moment. It has been deep. Suggesting that this earthquake activity has its source in inflow of new magma at depth. But it is the depth of those earthquakes it is the clue that magma is flowing again into El Hierro volcano.

This however does not mean that an new eruption is going to happen soon. So far the magma seems to be at the depth of 20 to 10 km and at the moment it is not moving at all. It is impossible to know when or if this magma is going to move at all.

Hydro-thermal zone off the coast of El Hierro Island

In the area where the eruption took place from October 2011 to February 2012. This area now has highly active hydro-thermal area. It is hard to know for sure how long it is going to be active. That depends on many factors. But activity should be noticed for at least next one to two years, possible even longer. But this hydro-thermal area off the coast of El Hierro Island is going to continue to create discoloration of the ocean for some time now. So when discoloration happens, it is not because the eruption has started again. It is because the hydro-thermal area activity is changing or some chemicals are getting mixed into the ocean creating discoloration of it.

Posted on

Strong earthquake in Japan, small earthquake swarm on Reykjanes Ridge in Iceland and more

Yesterday (14.03.2012) at 09:08 UTC there was an strong earthquake in Japan. The size of this earthquake was Mw6.9 and it had the depth of 10 km. Local tsunami warning was given out for the area closest to the epicenter of the earthquake. Aftershock activity has been ongoing after the main earthquake. The largest aftershock so far had the size Mw6.0. More details on the earthquake in Japan can be found here at EMSC web page.


Regional view of the earthquake in Japan yesterday morning. Copyright of this image belongs to EMSC.


Local view of this earthquake. It appears to have been in an subduction mountain, or close to it. Copyright of this image belongs to EMSC.

Iceland

Currently there is an earthquake swarm ongoing on the Reykjanes Ridge off the coast of Iceland. So far the strongest earthquake has reached the size of ML2.7. The depth is about 7 – 16 km. There is an slight chance that his might be an dike intrusion taking place on the Reykjanes Ridge. But this also might just be normal fault movement in the area. For the moment. There is no way to know for sure exactly why this earthquake swarm is taking place.


Reykjanes Ridge earthquake swarm as it is at 00:35 UTC. Copyright of this image belongs to Iceland Met Office.

South Norway

An minor earthquake took place in south Norway at 19:22 UTC. The size of this earthquake was ML3.5 according to EMSC. With the depth of 10 km. This earthquake was clearly felt in Norway according to EMSC and news reports of this earthquake. More details on this earthquake can be found here, on EMSC web page.

The regional view of the earthquake in south Norway. Copyright of this image belongs to EMSC.


Local view of the earthquake. It can clearly be seen here how close it was to several towns in south Norway. Copyright of this image belongs to EMSC.

This earthquake was clearly felt in Norway due the old crust that it took place it. But older crust conducts earthquakes better then new crust. Like the one that can be found in Iceland. That is due to lack of faults in it and the fact it is more dense with sediments then new crust. Earthquake in this area should be expected every 5 to 20 years or so. As there are old fault lines in this area, they sometimes break and create a earthquake.

Norwegian news about this earthquake.

Kanskje noen glass har falt ned fra bordet
Jordskjelv i Rogaland i kveld

New Britain region

Today at 21:13 UTC there was an Mw6.4 earthquake in New Britain region. The depth of this earthquake was 80 km according to EMSC. I do not know if this earthquake was felt or not. It at least has not been reported yet.


Regional view of the earthquake from EMSC. Copyright of this image belongs to EMSC.


Local view of the earthquake from ESMC. Copyright of this image belongs to EMSC.

More information about this earthquake can be found here, on EMSC web page.

Other

I am sorry for late post. I was flying back to Iceland today. It took awhile. I also had to do other things this evening before I could write about the most recent activity yesterday. This is going also going to happen later when I move back to Denmark. But I am going to post more details on that later.

Blog post updated at 12:11 UTC on 15.03.2012. Location of the earthquake in Norway was fixed.