Category: Dyke intrusions

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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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Update on El Hierro volcano activity

This is a short update on the activity in El Hierro volcano.

In the last 24 hours there have been no major changes in the activity of El Hierro volcano. No eruption has started yet. But earthquake activity continues with the same rate as in past few days. Magnitude of the earthquakes that are currently taking place is around ML1.5 to ML3.5, with the focal depth of around 20 km. But deepest earthquakes have the depth of around 28 km. While the shallowest earthquakes have the depth around 15 to 12 km. No harmonic tremor is currently taking place in El Hierro volcano. According to GPS data from El Hierro volcano. There is inflation taking place at the current moment. That means magma is injecting it self into the volcano at the depth of 20 km. There is already older magma from last year magma injection. Some of that magma erupted last year, but not nearly all of it. I do not know what happens if the new magma gets into contact with older magma that is in El Hierro volcano. There is also possibility that older magma from eruptions that took place thousands years ago is still in El Hierro volcano. That magma might be andesitic to rhyolitic in nature. If that is the case is impossible to know for sure. But this is always an risk with any volcano, regardless where they are located in the world.


Earthquake activity in El Hierro volcano during last four days. Copyright of this image belongs to IGN.


Earthquake activity during one week in El Hierro volcano. This map clearly shows the extent of the magma during this past week. Copyright of this image belongs to IGN.


Earthquake activity since 1. January 2012 in El Hierro volcano. Copyright of this image belongs to IGN.


Total amount of earthquakes in El Hierro volcano since activity started last year. Copyright of this image belongs to IGN.


Current earthquake activity in El Hierro volcano. No harmonic tremor is currently being detected in El Hierro volcano. Copyright of this image belongs to IGN.

It is difficult to day what happens next in El Hierro volcano. But I do believe that current earthquake activity is going to continue for the next few days to weeks. That activity depends on how much magma flows into El Hierro volcano. That flow might not be constant all the time. So there is going to be period of time with low activity during current events. When this is written, total of around 130 earthquakes have taken place in El Hierro volcano today (29. June 2012) so far.

Known eruptions in El Hierro volcano

Year 4790 BC (Radiocarbon)
Year 950 BC (+- 150 years)
Year 550 BC (+- 75 years)
Year 1677 (Uncertain eruption. Not confirmed.)
Year 1692 (Uncertain eruption. Not confirmed.)
Year 1793 May to 1793 June. Erupted on NW rift, GVP says that the eruption may have taken place at Volcán de Lomo Negro (?). But that is not confirmed or established at current time.
Year 2011 September to December, off the coast. Not on GVP web page.

Source: GVP web page, Hierro

Blog post updated at 20:16 UTC on 29.06.2012.

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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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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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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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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.

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Katla volcano warming up for an eruption. Small glacier flood continues

This is going to be a short blog post. As I am going to be short of table and a cheer for few more days.

It seems that Katla volcano is warming up for a eruption. As I did mention in last blog post. But there is more to this. As the glacier flood that started on the 28. April 2012 continues according to a email that I got from an geologist working at Iceland Meteorological Office. But that suggests two things. That there is currently an ongoing melting of glacier taking place in Katla volcano, or there is a slow drainage taking place from some area in Mýrdalsjökull glacier. But given increased conductivity following this it is clear that this water has been in contact with magma. But that can be seen with the increased conductivity in the water.

There have not been many earthquakes following this events. But from the earthquakes that have happened. It seems that most likely source for current events is close to or the same area that erupted in July 2011. But at the moment this is just speculation based on limited data. It has not been confirmed so far.


The harmonic tremor that started on 28. April 2012. This is Lágu Hvolar SIL station. Copyright of this picture belongs to Iceland Meteorological Office. Used with written permission.

This plot shows clearly how the harmonic tremor starts and continues at same level for several days. I do not know if the harmonic tremor is ongoing. But I find it likely, if the small glacier flood is currently going on (that was my last information, but things might have changed during the day). But it is hard for me to know that for sure. But based on latest data from the water monitoring system around Katla volcano, the spike in this glacier flood is most likely over for now. But it impossible to know what happens next in Katla volcano. All that can be done is to wait and see what happens next.

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Few earthquakes in Hamarinn volcano and Kverkfjöll volcano

After several weeks of quiet period, activity in the volcanoes that are close to or in Vatnajökull glacier. During the past few days there have been earthquakes in several volcanoes in Vatnajökull volcano. Today it is the Hamarinn volcano and Kverkfjöll volcano.

Hamarinn volcano (Loki-Fögrufjöll)

Hamarinn volcano had its first eruption in July 2011. This eruption was small and started without even a hit of earthquake activity. It created a glacier flood that topped at 2100 M3. It did not create any damge. But it filled a human made lake that is used for power production in this area. That eruption was short, it only lasted for about 24 hours, maybe even less. Today this area of Hamarinn volcano has been having minor earthquake swarm. But this does not mean it is going to erupt again. But it also shows that current activity in Hamarinn volcano is not over.


Earthquake activity in Hamarinn volcano today (08.04.2012). Copyright of this picture belongs to Iceland Meteorological Office.


The earthquakes seen on Skrokkalda SIL station. The earthquakes from Tungnafellsjökull volcano are also clear on this tremor plot from Iceland Meteorological Office. Copyright of this picture belongs to Iceland Meteorological Office.

Kverkfjöll volcano

Kverkfjöll volcano have been warning up to a eruption for some time now. When they might erupt is impossible to know at current time. But it is save to say that at present time, no eruption is going to take place any time soon. This however means that earthquakes are increasing in Kverkfjöll volcano. Most of the time there are just small earthquake swarms in Kverkfjöll volcano. No other changes have so far been noticed in Kverkfjöll volcano. But that is unlike what has been taking place in Askja volcano in the past few weeks.


Earthquake activity in Kverkfjöll volcano. This are just small earthquakes so far. Copyright of this picture belongs to Iceland Meteorological Office.


The tremor plot from the SIL station that is closest to Kverkfjöll volcano. It just barely shows the earthquakes that have been taking place in Kverkfjöll volcano. Copyright of this picture belongs to Iceland Meteorological Office.

After several weeks of quiet in Iceland it seems to be that the quiet period is over. But if it is going to going to result in any major activity is impossible to know at this point.


Volcanoes of Iceland. Copyright unknown, Google Inc. But the picture is from here (warning! Conspiracy web site.)