Category: Magma

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Earthquake activity in Katla volcano and on SISZ

It has been quiet for the past weeks in Iceland. I do not know if that is changing. But this is the short update of what has been taking place in Iceland earthquake wise during this quiet period.

Katla volcano

Since Katla volcano earthquake spike in late April to middle of June. Sine then it has been rather quiet in June and what has passed of July. Today and yesterday there has been some earthquake activity in Katla volcano. But nothing like was seen in April to June.


Earthquake activity in Katla volcano during past few days. Copyright of this picture belongs to Iceland Meteorological Office.

South Icelandic Seismic Zone (SISZ)

Intresting earthquake activity has been taking place in South Icelandic Seismic Zone for few days now. Currently the activity is on the northern end of the fault that broke in the year 2008. This is most likely just an earthquake swarm in the fault area that is continuing to adjust after the Mw6.3 earthquake in the year 2008.


Earthquake activity on SISZ during the past few days and hours. Copyright of this picture belongs to Iceland Meteorological Office.

As for SISZ. This is just an earthquake activity. There is no volcano activity in this area of Iceland. But SISZ is a fault zone that moves N-S (W-E compared to Reykjavík). So with every major earthquake on SISZ, it is slowly moving south as the new rift zone (Iceland East rift zone) moves south at the same time. This is a slow progress. Takes millions of years and has been ongoing for million of years already.

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Continuous earthquake activity in El Hierro volcano

There have not been great changes in El Hierro volcano. Currently no eruption has taken place. There are also no signs of magma movement on tremor plots on seismometers stations that are located on El Hierro Island. The dike intrusion in El Hierro volcano is continues, but at slower rate then before. But that it is continuing means there is continued risk of an eruption where the earthquakes are currently taking place. Currently the rate of earthquake is around 3 to 8 earthquakes during the hour. Most of the earthquakes are around ML1.5 to 3.4 in magnitude. Please note that I am missing all earthquakes with the magnitude of ML0.0 and up to ML1.5. So there might well be a lot more earthquakes taking place in El Hierro volcano then I am seeing on IGN web page.


Current tremor plot of El Hierro volcano. The spikes are earthquakes in most cases. Copyright of this picture belongs to IGN.


Last 36 hours of earthquakes in El Hierro volcano. It shows clearly where magma has pushed it self into the crust. Creating inflation and earthquakes. The spikes are earthquakes in most cases. Copyright of this picture belongs to IGN.


Past 7 months of activity in El Hierro volcano. This map shows well how magma has slowly been injecting it self into El Hierro volcano during the past few months. Some of the earthquakes there are also just tectonic earthquakes, due to stress changes that injection of magma creates in the crust. The spikes are earthquakes in most cases. Copyright of this picture belongs to IGN.

According to official reports. The inflation of El Hierro volcano is around 10 cm according to official reports, or around that. I am having hard time finding the official news reports on the inflation in El Hierro volcano at current time. For the moment, the current situation is stable for the moment. But when that might change is impossible to know for sure. But there is magma inside El Hierro volcano, so there is an increased risk of some of that magma finding it’s way to the surface and erupting. But that might be out in the ocean as last time, or on land. It is impossible to know that for sure until an eruption starts. For the moment, nothing can be done the to watch and monitor the current situation in El Hierro volcano.

Other

It seems that Icelandic volcanoes and fault zones are on some type of summer vacation for the moment. So I am covering other things while the quiet period in Iceland is currently ongoing.

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Short update on activity in El Hierro volcano, Canary Islands / Corto sobre la actividad de actualización en el volcán de El Hierro, Islas Canarias

This is just a short update on El Hierro volcano activity. I plan on making a longer blog post tomorrow when I am not so tired.

Current earthquake activity in El Hierro volcano is continues. The rate of earthquakes taking place in El Hierro volcano is about 10 earthquakes pr 1 hour. With high up to 20 earthquakes pr hour, and down to 2 earthquakes pr 1 hour. The rate of earthquakes with the magnitude larger then ML3.0 is about the same. They happen every few hours at random intervals. For the past few days a cluster of large earthquakes takes place every 10 to 12 hours. This pattern is not something to trust in, as it is going to change without warning. But it is controlled by inflow of magma at depth under El Hierro volcano. Most earthquakes take place at around 20 km depth, as that is where magma is being injected into El Hierro volcano. That however does not rule out the possibility of magma having reached higher up in the crust. Some of the earthquake taking place in El Hierro volcano are crustal stress earthquakes. As magma and inflation of El Hierro volcano is changing the stress in the crust close to it. The

Based on the data from last years events, the magma now is up to 5 km depth in the crust. That magma is for the moment not moving. It is just staying where it and cooling. That might change without warning if something changes inside El Hierro volcano. It is impossible to predict such event with any manner of accuracy. This magma is most likely going to stay where it is and cool off for the next few centuries (this is a different magma sill that is not creating so much earthquakes at the moment). The current magma injection is going to start an eruption in my opinion. It is just question of when and where. It is not a question of “if” in my opinion (non-professional opinion). Update: There are two or three magma sill in El Hierro volcano at present time. Not all of them are going to erupt. Current magma sill that is forming now is however going to erupt in my opinion. That sill formation has been creating earthquakes and inflation during the past two weeks. I know this sounds to be contradicting it self. But the situation in El Hierro volcano is a lot more complex then it seems.

I believe this location to the most likely place for an eruption. More or less. But there is also a risk of magma going somewhere unexpected. As is the risk with all volcanoes that erupt in the same manner as El Hierro volcano.


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Inflation has also been sharp following this earthquakes activity. With some areas reporting up to 120mm inflation during short period of time. This is common for volcanoes like El Hierro volcano. Some of this inflation areas might erupt in a fissure vent eruption. When and where are in this case impossible to predict until an eruption actually starts. This types of eruptions are normally not dangerous unless they are close to human habitat. This fissure vents might however be large in length, from several meters in length and up to several km long.

It is hard to know what happens next when it comes to volcano, any volcano that is. What happens in a volcano is poorly understood by everyone. So what happens next in El Hierro volcano is anyone guess. But I find it to be good advice for people living on the Island of El Hierro to stay alert for sudden change in El Hierro volcano behavior.

Spanish / Español (via Google Translate)

Esto es sólo una breve actualización sobre la actividad del volcán de El Hierro. Mi plan es hacer un mañana después de blog cuando ya no estoy tan cansado.

La actividad sísmica actual en El Hierro volcán continúa. La tasa de los terremotos que tienen lugar en El Hierro volcán es de unos 10 terremotos pr 1 hora. Con alta hasta 20 horas pr terremotos y terremotos de hasta 2 pr 1 hora. La tasa de terremotos con la magnitud más grande que ML3.0 es aproximadamente la misma. Se producen cada pocas horas a intervalos aleatorios. Para los últimos días un grupo de grandes terremotos se lleva a cabo cada 10 a 12 horas. Este patrón no es algo que confiar, ya que va a cambiar sin previo aviso. Sin embargo, está controlado por flujo de magma en las profundidades del volcán en El Hierro. La mayoría de los terremotos tienen lugar en torno a 20 km de profundidad, ya que es donde el magma se está inyectando en el volcán El Hierro. Que sin embargo no descarta la posibilidad de que el magma de haber alcanzado más arriba en la corteza. Algunos de los terremotos que tienen lugar en El Hierro son los sismos del volcán corteza de estrés. Cuando el magma y la inflación del volcán El Hierro está cambiando la tensión en la corteza de cerca a él. La

Con base en los datos de eventos de los años últimos, el magma es hasta una profundidad de 5 km en la corteza. Ese magma es por no pasar el momento. Se acaba de estar donde y refrigeración. Eso podría cambiar sin previo aviso si algo cambia en el interior del volcán de El Hierro. Es imposible predecir tal caso con cualquier forma de precisión. Este magma es más probable que va a quedarse donde está y refrescarse durante los próximos siglos (esto es un umbral de magma diferente que no es la creación de terremotos, por lo tanto en este momento). La inyección de magma en curso va a comenzar una erupción en mi opinión. Es sólo cuestión de cuándo y dónde. No es una cuestión de “si” en mi opinión (no profesionales opinión) . Actualización: Hay dos o tres alféizar de magma en el volcán de El Hierro en la actualidad. No todos ellos van a entrar en erupción. Alféizar de magma actual que se está formando ahora es, sin embargo va a estallar en mi opinión. Que la formación de solera ha sido la creación de terremotos y de la inflación durante las últimas dos semanas. Sé que esto suena a contradicción en si mismo. Pero la situación en El Hierro volcán es mucho más compleja de lo que parece. Link: Lámina (geología) (Wiki)

Creo que esta ubicación para el lugar más probable para una erupción. Más o menos. Pero también existe un riesgo de magma ir a un lugar inesperado. Como es el riesgo con todos los volcanes que hacen erupción de manera semejante como El volcán Hierro.


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La inflación también ha sido fuerte después de esta actividad los terremotos. Con algunas zonas informar a la inflación 120 mm durante el período de tiempo corto. Esto es común para los volcanes como el volcán El Hierro. Algunas de estas áreas la inflación podría entrar en erupción en un fisura de ventilación erupción. ¿Cuándo y dónde están en este caso imposible predecir una erupción hasta que realmente empieza. Este tipo de erupciones normalmente no son peligrosos a menos que se acercan al hábitat humano. Estos respiraderos de fisuras sin embargo, podría ser de gran longitud, de varios metros de longitud y de hasta varios kilómetros de largo.

Es difícil saber lo que sucede a continuación en lo que respecta al volcán, un volcán que es. Lo que ocurre en un volcán es poco comprendido por todos. Entonces, ¿qué ocurre a continuación en el volcán El Hierro es que nadie adivine. Pero me parece que sea un buen consejo para las personas que viven en la isla de El Hierro para mantenerse alerta para el cambio repentino en el comportamiento del volcán de El Hierro.

Blog post updated at 01:17 UTC on 04.07.2012. Explanation added to the blog post.

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Analyze on events in El Hierro volcano

This is a short analyze of what is happening in El Hierro volcano. What is taking place in El Hierro volcano has an simple explanation. What is taking place in El Hierro volcano is an dike intrusion. This creates earthquakes as new magma is injected into the crust. This is also creating inflation on the surface. It has been reported so far the inflation is 20mm up, 20mm east, 20mm north. This can clearly be seen on GPS data that was released today.


The inflation according to IGN. This is recent GPS data. Copyright of this image belongs to ING/AVCAN

The dike intrusion into El Hierro volcano is creating sill in it. While new magma is being injected into the volcano. It is going to mean earthquake activity and a lot of it. Currently there are three older sill that have formed in El Hierro volcano. This sill clearly appear on images that show the earthquake pattern over the past one year in El Hierro volcano.


Earthquake activity marks the sill and older magma injection areas in El Hierro volcano. Copyright of this image belongs to ING/AVCAN


Earthquake activity in El Hierro volcano as it is today. This is accumulated earthquake activity sine current earthquake swarm started. Copyright of this image belongs to ING/AVCAN

What happens if the new injection gets into contact with the old inection is anyone guess. But new magma, if it gets in contact with an older magma might mobilize it. It might not mean an eruption. But earthquake activity might get really intense for a while. A lot more intense then it already is today. With earthquake well above magnitude ML3.0 and up to ML5.0 (depending on the stress of the crust in the area).


Earthquake activity in El Hierro volcano today. So far no harmonic tremors have been detected. But that might change without warning if the magma finds a path to the surface. Copyright of this image belongs to ING/AVCAN

When I write this I see that El Hierro volcano has had it first ML4.0 earthquake as I did fear yesterday might happen. But I made a comment on that on AVCAN Facebook page yesterday (Somewhere, I have no idea where it is located).

References:

Dike (geology) (Wiki)
Sill (geology)
Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption (http://geoscience.wisc.edu/)

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New activity in El Hierro volcano, Canary Islands

While this blog now covers mostly Icelandic volcanoes. I am going to cover other volcanoes from time to time.

New earthquake activity started around 21:26 UTC in El Hierro volcano with an earthquake that had magnitude ML3.1 with the depth of 20 km. Largest earthquake so far had the magnitude of ML3.8 and the depth of 19 km. Depth of this earthquake swarms is mostly around 20 km. At current time nothing suggests that new eruption is about to start in El Hierro volcano. But that might change without any warning if the magma finds an clear path to the surface. But that would be detected by seismometers on El Hierro Island. So the risk of such events taking people by surprise is minimal. My automatic earthquake counter for El Hierro volcano shows that at least 143 earthquakes have taken place today so far. For the moment the earthquake swarm seems to have stopped. But I expect it to resume at any time and without any warning at all.


Earthquake activity today at El Hierro volcano. This picture is from 18:08 UTC. Copyright of this picture belongs to IGN.


Location of the earthquakes, with depth in El Hierro volcano. This image is from 25. June at 18:09 UTC. Copyright of this picture belongs to IGN.

I do not know what is going to happen next in El Hierro volcano. But current status of the volcano is clearly something that needs to be and is monitored today. It is impossible to know for sure what is going to happen next in El Hierro volcano. But I am not going to rule out an eruption at this point.

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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.

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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.

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New earthquake swarm in Katla volcano on 11. June 2012

Today from 04:00 to around 08:00 UTC this morning. There was an earthquake swarm in Katla volcano. This earthquake swarm was not large in the magnitude of the earthquakes. With the largest earthquakes being around ML2.0 in magnitude. There has been slight increase in conductivity in Múlakvísl river following this earthquake swarm. That suggests water is now leaking from hydro-thermal vents in Mýrdalsjökull glacier. So far no change in harmonic tremor has been seen. So for now, this are just earthquakes taking place inside Katla volcano caldera.


The earthquake swarm in Katla volcano this morning. Copyright of this picture belongs to Iceland Meteorological Office.

It is difficult to know what happens next in Katla volcano. As it is bit unclear what is exactly taking place in Katla volcano. With the lack of harmonic tremor following this earthquake swarms. This simply might just be normal summer earthquake swarms taking place. But Katla volcano is well known for that type of behavior during the summer in Iceland. With the most earthquake activity taking place in July and August.

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Earthquake swarm in Katla volcano yesterday (07.June 2012)

Yesterday there was an earthquake swarm in Katla volcano. Over 50 earthquakes have been recorded so far. But this earthquake swarm stopped yesterday at 16:22 UTC. Most of the earthquakes where shallow, with depth less then 1 km. Largest earthquake had the magnitude of ML2.5. No harmonic tremor was detected following this earthquake swarm. But that is unlike what did happen last year, when a similar earthquake swarm took place in Katla volcano.


Earthquake activity in Katla volcano yesterday (07. June. 2012). The main areas appear clearly on this map. The small dot SE on the caldera rim is an area that became active after last years minor eruption. What is taking place there is still an mystery. Copyright of this picture belongs to Iceland Meteorological Office.

This activity appears to be similar to what happened around 9th July, 2011. But no harmonic tremors are taking place in Katla volcano following this earthquake swarm.


Earthquake activity in Katla volcano on 9. July 2011. This good to compare the earthquake activity yesterday (image above this one). Copyright of this picture belongs to Iceland Meteorological Office.


The ML2.98 magnitude earthquake that happened in Katla volcano yesterday (07. June. 2012). This is the earthquake as it was recorded on Skeiðflöt geophone station. This image is released under Creative Commons License. See License page for more details.


Same earthquake as above. But filtered at 1Hz and this is how the earthquake appeared in Heklubyggð geophone station. This image is released under Creative Commons License. See License page for more details.

So far this is just an earthquake swarm. As there are no harmonic tremor signal taking place as the earthquake swarm is taking place. I do not know if there has been any glacier flood following this earthquake swarm. But if there was. It would mean that hydrothermal vents under Mýrdalsjökull glacier have been emptying out. It happens regularly in glacier such as Mýrdalsjökull glacier.

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Special report: New magma injection at depth in El Hierro volcano

While I have returned to just covering Iceland volcano and earthquake activity. It does not mean that I have stopped to watch the earthquake activity in El Hierro volcano at present time.

New earthquake activity with the depth of 15 to 28 km have been taking place in El Hierro volcano today (04.06.2012). Minor earthquake activity has also taken place on 29. May, 1. June, 3. June. But this where not many earthquakes. Nothing suggests that eruption has resumed in El Hierro volcano. However an new injection of magma into El Hierro volcano might have increased hydro-thermal activity in earlier eruption vents, or moved older magma that is already high up in the fissure that was eruption. That however does not mean that the eruption has resumed. But there is nothing in the data from El Hierro volcano to suggest that an eruption has resumed at this point.

For the moment, it is mostly quiet in El Hierro volcano. I fully expect that to continue for the time being. At least it is clear that more needs to happen in El Hierro volcano before an new eruption starts in El Hierro volcano. So for the moment, there is nothing to worry about in my opinion.