This morning (20-May-2015) a swarm of deep earthquakes took place in Katla volcano. This earthquake activity was at depth and it means that magma was moving or dyke intrusion taking place at depth.
Earthquake activity in Katla volcano this morning. The earthquake swarm took place close to 1918 eruption site. Copyright of this image belongs to Icelandic Met Office.
Deepest earthquake in this swarm had the depth of 28,9 km. Shallowest depth was 17,3 km. At this depth there is only magma that can create earthquakes, since crust at this depth in Iceland almost never has earthquakes (it might happen, but is rare event) that is not related to magma movements. This activity is something that needs to be monitored since it might suggest that conditions inside Katla volcano might be changing. There is no way to confirm at this point that to be the case. At the moment there is nothing to suggest that eruption is imminent in Katla volcano at this point. This deep earthquake activity appears to be over for now.
Almannavarnir put out a warning yesterday (19-May-2015) about increased risk of man made earthquakes in Hengill volcano. This happens when a water is pumped down into the ground it changes the pressure in the rock and creating earthquakes as a consequence. There is a risk of earthquakes with magnitudes up to 4,5 or larger. The first pumping down of this leftover water is expected to end by 19-June-2015.
Icelandic News about this
Vara við jarðskjálftum á Hengilssvæðinu (Rúv.is, Icelandic)
Niðurdæling vegna hitamengunar að hefjast (Rúv.is, Icelandic)
It was reported on Rúv News today about a new study that came out few days ago. In this study according to Rúv News the ash cloud from Eyjafjallajökull (2010) and Grímsfjall (2011) volcanoes where larger then appeared on satellite images. Meaning the ash could was covering larger area then appeared on images from space. The grain size in this eruptions was also underestimated. The decision to close down the airspace as was done in both eruptions was correct.
More details can be found here.
Viðbrögðin voru hárrétt (Rúv.is, Icelandic, audio in Icelandic)
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There is a good article about how Bárðarbunga volcano collapsed during it’s six month long eruption in Holuhraun. The most recent data (the work on Bárðarbunga volcano is far from over even there is no eruption taking place currently) show that Bárðarbunga volcano did in fact collapse. This collapse was not marked by a big explosion, but rather slow subsidence of Bárðarbunga volcano over a large area. Holuhraun eruption is the largest eruption in Iceland for the past 230 years, both in magma and size of the eruption.
More details can be found here.
Iceland’s Bárðarbunga-Holuhraun: a remarkable volcanic eruption (blogs.egu.eu)
Today (11-May-2015) a glacier flood started from Grísmfjall volcano caldera. This is not a dangerous glacier flood due to its small size. There is however a danger from sulphur gases and other gases that dissolve when the pressure is dropped on the water. If people get too close to the Gígukvísl glacier river where the flood comes from Vatnajökull glacier they risk a damage to there eyes and lungs due to burning effects from the gases in the air.
Increased harmonic tremor from Grímsfjall volcano. Copyright of this image belongs to Icelandic Met Office.
There is now a increased harmonic tremor from Grímsfjall volcano. It is not clear why that is, it is either the glacier flood or hydrothermal vents boiling at the bottom of the lake due to the sudden pressure release on them. There is nothing suggesting that an eruption is going to follow this glacier flood from Grímsfjall volcano. Last glacier flood took place in 2014.
Lítið hlaup í Gígjukvísl (Rúv.is, Icelandic)
There is currently a high risk of rock collapse in Ketilbjörg cliffs in north-west Iceland. This area is located north of Sauðárkrókur town. The area is now extremely dangerous due to the fact that the rock can fall of it’s location without warning. This are big rocks that are breaking off and falling into the coastline, many of them having the size of small houses or cars. If people travel to this area they should not go to the edge where cracks are in the ground. Doing so puts your life at risk.
Enn hrynur úr Ketubjörgum (Rúv.is, Images, Icelandic)
It was noticed today that a landslide took place in Dyrhólaey island. This landslide is not big, but it cut a hiking path that goes close to the cliff edge in this area. Most of the rock in the island appears to be unstable according to the news today, but that instability is hard to see on the surface. In 2012 four people fell off that cliff, all survived the 40 meter drop in this location when they did accidentally step over the cliff edge.
Icelandic news and images (all text is in Icelandic)
Skriða tók með sér gönguslóða í Dyrhólaey (Rúv.is, images, Icelandic)
Stór skriða féll í Dyrhólaey: „Stígurinn sem alltaf er genginn liggur bara beint út þetta“ (Vísir.is, Icelandic, images)
Stórt skarð í stígnum (mbl.is, Icelandic, images)
During the week there has been a swarm of minor earthquakes in Askja volcano. All of the earthquakes have been small and none have reached magnitude 2,0 far as I know.
Askja volcano is the volcano most south on this image (the volcano on the end). Copyright of this image belongs to Icelandic Met Office.
There is nothing suggesting that current earthquake swarms are due to magma movements at shallow depths. This is rather hydrothermal activity changes in the volcano due the it being warmed up by new magma entering it and warming up groundwater inside the volcano. That has happened before in earlier eruptions and is documented, the time scale of such changes is not documented far as I know.
Askja volcano started for prepare for an eruption phase in 2010, so far nothing suggest that an eruption is imminent, but it remains a question if the push from Bárðarbunga volcano has changed anything in Askja volcano.
Article updated at 18:56 UTC.
Yesterday (01-May-2015) a minor dyke intrusion took place in Katla volcano. This dyke had depth down to 26,9 km and up to 18,5 km. This is the second dyke intrusion in this are in short space of time. Largest earthquake in the following earthquake swarm had the magnitude of 2,0.
Dyke intrusion in Katla volcano (dense cluster of earthquakes). Copyright of this image belongs to Icelandic Met Office.
While this doesn’t signal imminent eruption in Katla volcano this activity does have me concerned due to past experience with activity in Katla volcano. This might die out, but there is no way to know for sure. All that can be done is to wait and see what happens next in Katla volcano.
Notice on Grímsfjall volcano
There has been a slight increase in earthquakes in Grímsfjall volcano. This suggest that the volcano is about to be ready for its next eruption. Earlier eruptions took place 2011, 2004, 1998 … etc. It is impossible to know when or how big next eruption in Grímsfjall volcano is going to be.
Today (30-April-2015) a minor dyke intrusion took place in Bárðarbunga volcano. This dyke intrusion was small and appears to be over for now. This does show that current activity in Bárðarbunga volcano is not over even if the eruption in Holuhraun has ended.
The dyke intrusion in Bárðarbunga volcano is a small cluster of earthquakes, it can be found on this image as three orange dots and one red dot. Copyright of this image belongs to Icelandic Met Office.
Largest earthquake that appeared in the following earthquake swarm took place had the magnitude of 2,1. Depth of this earthquake swarm was around 17 km and going up to 5,3 km. Nothing suggest that at current time this dyke has reached the surface and no harmonic tremor was detected during the time this dyke intrusion took place in Bárðarbunga volcano. More dyke related activity should be expected in Bárðarbunga volcano in next few months to years. Other earthquakes in Bárðarbunga volcano are due to stress changes in the crust due to deflation the volcano came under during the eruption in Holuhraun, total subsidence of Bárðarbunga volcano during that eruption has been measured 62 meters. Current rifting activity is not over in this area even if no eruptions are taking place at the moment.