Interesting earthquake activity took place in Vatnajökull glacier today (03.06.2013). This earthquake activity took place just south of Grímsfjall volcano, that last erupted in the year 2011.
The earthquake activity south of Grímsfjall volcano. Copyright of this image belongs to Icelandic Meteorological Office.
This earthquake activity is interesting, since it started after the eruption in Grímsfjall volcano at that area. It has been suggested that this activity is due to stress changes in this are, following the eruption in Grímsfjall volcano in the year 2011.
Earthquake activity in the same area in week 21 in the year 2011. Copyright of this image belongs to Icelandic Meteorological Office.
I am not sure what is going on in this area, no volcano is known, or volcano fissure is known in this area. But that might well just be because this area is covered with a thick glacier. What makes this also interesting is the fact this area has been having earthquake activity since the year 2011 and there doesn’t seems to be any end in sight. This is clearly something worth keeping a eye out for, even if nothing happens in this area for a long time.
The latests news is that a glacier flood has started in Skaftá river. At the moment this glacier flood does not appear to be big, as there was also a glacier flood in this river last year. Because of this short time, there has not been a lot of water collected in the western cauldron that is emptying now. It was clear today that it was the western cauldron that had emptied when scientists did fly over the area earlier today.
This glacier flood is often early event and has been since the year 1955. Following this glacier flood there is often spike in harmonic tremor because magma goes on the move due to sudden pressure release in this area. So far it has not been able to trigger a eruption in Hamarinn volcano. It remains to be seen if that has changed or not.
Icelandic News about this
Hlaup hafið í Skaftá (Rúv.is, Pictures, Icelandic)
Rennsli eykst í Skaftá (Vísir.is)
Hlaupið komið í Skaftá (mbl.is)
At current time (around 20:30 UTC) it has been observed that no glacier flood has started in Skaftá river. But the glacier flood is expected to start in the river around midnight, but the river might start to grow around 19:00 to 21:00 UTC. According to latest news the river has however started to get darker and conductivity in the water has started rise since this morning, but that was the signal that a glacier flood was about to start. Glacier flood tremor have also been dropping in the last few hours according to the latests news that I have seen (but I am hoping for a update on that detail).
The source of this glacier flood is a hydrothermal area in Hamarinn volcano (part of Bárðarbunga volcano). This area also did have a glacier flood last year. But last year there where two glacier floods in Skaftá river in June 2010, see reports here in Iceland at Icelandic Met Office web page.
This hydrothermal area in Hamarinn volcano is in two cauldrons in the Vatnajökull glacier. With time they fill with water that then breaks ice when the pressure is enough in the cauldrons due to water levels. It remains a question if the surprise glacier flood earlier this month from Hamarinn volcano has something to do with this. But at current time that is only speculation. But if the hydrothermal area is unusually highly active, or there has been some change it is hard to know for sure the size of this glacier flood.
Currently however the experts are expecting a small glacier flood due the fact there where two glacier floods from this area last year. But we however have to wait until midnight until we know what is the actual size of this glacier flood.
Icelandic News about this
Skaftárhlaup ekki enn hafið (Rúv.is)
Skaftárhlaupið komið í byggð eftir sólarhring (Vísir.is)
Engin merki um hlaup ennþá (mbl.is)
There seems to be a small harmonic tremor spike taking place in Hamarinn volcano (Bárðarbunga volcano) at the moment. This tremor spike is not strong
at the moment. This tremor spike appears to have been pre-seeded by few long period earthquakes (not all of the earthquakes seen on Skrokkalda are from Hamarinn volcano, few are from Katla volcano), but that suggests that magma is on the move in Hamarinn volcano. But this would the second harmonic tremor in a time period of 48 hours it seems.
The harmonic tremor spikes can be seen at the end of this tremor plot. Copyright of this picture belongs to Icelandic Met Office.
Currently it is impossible to know what happens in Hamarinn volcano. As it’s pre-eruption behaviour is rather unknown. But if there is a eruption in this area I am expecting a lot of earthquakes, with size well over ML3.0.
Blog post updated at 16:20 UTC.
After the glacier flood that took place last night and today the source of this flood has finally been found. According to the news the source of this flood is a new hydrothermal area inside the Bárðarbunga fissure swarm. But this new hydrothermal area is located in Hamarinn volcano (also known lokahryggur or Loki-fögrufjöll), sadly the news does not say exactly where it is located. Just that it located in western Vatnajökull glacier. This flood did go down the river Sveðju and into the Hágöngulón lake (human made lake) that did swallow it whole according to the news. The overflow after the dam lake was full did go into an even larger natural lake, that did not feel any effects of this glacier flood.
In terms of size this glacier flood was larger then the glacier flood in Mýrdalsjökull glacier last week. But that was only about 2000 m3/sec, but this was somewhere around 2200 m3/sec. But this are the numbers that I have seen in the news. But this are not confirmed numbers and might be subject to change on later date.
Other then this activity. It has been rather quiet in Iceland in terms of earthquake and volcano activity.
Icelandic news about this.
Áður óþekkt jarðhitasvæði fundið (Rúv.is, Icelandic)
Virkjunarlónin gleyptu gríðarstóra flóðbylgjuna (Vísir.is, Icelandic)
Órói við Lokahrygg í Vatnajökli (Icelandic Met Office, Icelandic, Pictures)
The harmonic tremor that started yesterday has been confirmed to be coming from Hamarinn volcano (Bárðarbunga volcano), but they are also known as Loki-Fögrufjöll in GVP database.
So far there is nothing that indicates an eruption is taking place at the moment in Hamarinn volcano. But that might change without warning. At the moment nobody is sure where the glacier flood is coming from. But this appears to be a new area of hydrothermal activity in Hamarinn volcano that is releasing water at the moment. This new hydrothermal area is most likely created by new dike intrusions into the bed rock in the affected area. There are no pictures of the affected area, as the area is impassible to air plains at the moment due to cloud cover or fog. Lack of earthquakes also makes it hard to locate the source of this glacier flood.
Currently the glacier flood has peaked and is getting lower. There not expected to be any damage from this glacier flood on human structures or roads. This area of Iceland is unpopulated. The water is going into large lakes in the area where the effects of this glacier flood are almost none. The glacier flood did flow into a dam lake that is collecting water from rivers that this glacier flood did go into. This did make the lake rise about 70 cm in several hours and fill it. No damage is expected from this glacier flood to the dam or other structures in this area connected to the dam. But it is estimated that 26 gigaliters did flow into the dam lake during the night from this glacier flood.
Harmonic tremor at 12:59 UTC, this is Skrokkalda SIL station. At this time it had been dropping down. But starting to rise again after that when this is written. Copyright of this picture belongs to Icelandic Met Office.
This is the harmonic tremor at 12:59 UTC on Grímsfjall SIL station. It is bit hard to see it due high background noise on this SIL station. Copyright of this picture belongs to Icelandic Met Office.
So far this is just a glacier flood and nothing else. But that might change if an eruption starts in this area. But that is no way certain that it is going to happen now. We just have to wait and see what happens in Hamarinn volcano.
Icelandic News about this.
Hágöngulón fylltist í hlaupinu (mbl.is, Icelandic)
Hlaup undan Köldukvíslarjökli (mbl.is, Icelandic)
Jökulhlaup undan Vatnajökli (Vísir.is, Icelandic)
Hlaupið í rénun (Vísir.is, Icelandic)
Órói við Vatnajökul (Rúv.is, Icelandic)
Flóð undan Vatnajökli (Rúv.is, Icelandic)
It seems that there have been few glacier quakes in Mýrdalsjökull glacier over the past few days. This glacier quakes are created by rain or some other movement in the glacier it self. This glacier quakes normally take place when there is heavy rain, or when the glacier is just moving because of water that is flooding below it. Sometimes glacier quakes also appear to happen around hydrothermal areas, but those might be harder to detect due to distance.
While not on the automatic earthquake list due how poor quality the glacier quakes are. It is still possible to see them on the tremor charts that Icelandic Met Office has on-line.
Glacier quakes seen on tremor chart of Icelandic Met Office. The quakes create an pattern of spikes on the tremor chart, it mixes into the other earthquake activity currently taking place in Katla volcano. Copyright of this picture belongs to Icelandic Met Office.
Same as above. Bust just stronger then on Lágu Hvolar SIL station. Copyright of this picture belongs to Icelandic Met Office.
This glacier quake activity has also been taking place in Vatnajökull glacier. But the force for the glacier earthquakes in Vatnajökull glacier seems to be weather (rain and sun), rather then hydrothermal activity.
Glacier quakes can be seen close the 28th June line on the tremor chart. But most of the activity does not get recorded due to strong wind at the same time. Copyright of this picture belongs to Icelandic Met Office.
Other then this, it is quiet in Iceland. Both in earthquakes and volcanoes.
Update: I did update the history list for eruptions in Iceland to include the last eruption in Grímsfjall volcano.
Blog post updated at 22:36 UTC.
In my last blog post I did tell the news about the possibility about a eruption in the Kistufell volcano field. But that field is a part of Bárðarbunga volcano system and has a lot of earthquake activity since the beginning of earthquake recording in Iceland.
In the tonight news on Rúv about this area, Páll Einarsson geologist at University of Iceland says in the news on Rúv that there is a good reason to worry about this area. As it is one of the most active one in Iceland, but it is directly above the mantle plume under Iceland. Páll Einarsson also says in the news on Rúv that before the eruption in the year 1996, that took place in a volcanic ridge now named Gjálp there was a increase in earthquake activity in Kistufell field.
But due to continues earthquake activity there is it hard to know what is exactly going on there. Páll Einarsson also says in the news on Rúv that it is a problem that this area of Iceland lacks the proper coverage with seismometers. But they are few in this area and that makes it harder to detect the depth and the location of the earthquake that take place in this area of Iceland.
After the Eyjafjallajökull volcano eruption in the year 2010. It seems that geologist in Iceland take earthquake swarms more seriusly then they did before. As they did learn from Eyjafjallajökull volcano eruption that not all volcano start with few earthquakes just before they erupt, as is common with few volcanoes in Iceland.
The news from Rúv on this matter. Use Google Translate to understand.
Full ástæða til að hafa varann á (Rúv.is)
The quiet time in Iceland continues with few to no earthquakes. Besides the strong Mw6.2 earthquake in Jan Mayen Island (Belongs to Norway, regional to Iceland geological area in my personal view) there is nothing happening.
On the night of 25th of January there where ice-quakes in Vatnajökull glacier. This appears to have happened due to heavy rain in that area from the 21st of January. But that can make the glacier move suddenly and that makes the ice-quakes. Icelandic Met Office has some pictures of this activity.
Picture is from Icelandic Met Office web site. Copyright belongs to them.
Ice-quakes in this plot appear as spikes. As can be seen a lot of ice-quakes took place in Vatnajökull glacier during the heavy rain.
Picture is from Icelandic Met Office web site. Copyright belongs to them.
A high detail of the ice-quakes. As can be seen, the ice-quakes look different then normal earthquakes. This is because ice is not as dense then rock and is under less pressure, and therefor breaks in a different way.