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Deep earthquake in Hofsjökull volcano

Among the most quiet volcanoes in Iceland is Hofsjökull volcano. It has not erupted in at least 12.000 years from it’s main crater (far as I know). But minor fissure eruptions have taken place in the last 12.000 years in the area around Hofsjökull volcano. But they are undated far as I know. Because of that it is now known when the last eruption took place in Hofsjökull volcano. In terms of Icelandic volcanoes, Hofsjökull volcano is more complex then most. South of it lies the Kerlingafjöll volcano. A volcano known for it’s heavy hydrothermal activity. But Kerlingafjöll volcano has not erupted in historical times in Iceland. But they might have erupted in the last 12.000 years without me knowing about it. In the case of Hofsjökull volcano looks are deceiving. According to a geological map that I have of Iceland, in the case of Hofsjökull volcano it has a second magma chamber and a central volcano inside the SW part of it. That volcano is unnamed for oblivious reasons. That volcano might well behave differently then Hofsjökull volcano it self. But I would theorise that this intergrated central volcano inside Hofsjökull volcano is going to be active when Hofsjökull volcano is.

The icecap in Hofsjökull volcano is deep. At it’s deepest point it is 650 meters deep at the most. The deepest points of the icecap are in the main caldera of Hofsjökull volcano. If Chaitén volcano in Chile has teaches geologist anything. It is that a long dormant volcanoes don’t need a long time to go from dormant to active eruption. That is why I find it worrying that deep earthquakes have started to appear in Hofsjökull volcano, even if they are extremely rare so far.

Over the past ten years or so there has been a slight increase in earthquake activity in Hofsjökull volcano along with increase in hydrothermal activity. But so far it has just been a minor earthquakes. The strongest ones getting up to ML3.0 at the strongest. No earthquake swarm have ever been recorded in Hofsjökull volcano to my knowledge (since recording begin in Iceland).. Last earthquake swarm was recorded in Hofsjökull volcano in the year 1999, then a earthquake swarm of 22 earthquakes took place, all of those earthquakes where just minor earthquakes. Besides being one of Iceland largest volcanoes, its location also makes it extremely dangerous. As it is located in the middle of Iceland, and a glacier flood from it could go many different ways down to the ocean and over large populated areas in Iceland. The increase in hydrothermal activity started in Hofsjökull volcano in the year 1994 or about that time. It was at least first documented in that year. A sulphur smell was recorded when the homoeothermal vent was checked out that year in Hofsjökull volcano. Increase in hydrothermal activity in Hofsjökull volcano is interesting as it is followed by a slight increase in earthquake activity over a long period of time.


Location of the two earthquakes. The deep earthquake is the one closer to the caldera. This picture is from Icelandic Met Office web site. The copyright of this picture belongs to them.

The earthquake that started me to get worrying about Hofsjökull volcano is the earthquake that took place 10:11 UTC on 5. April 2011. That earthquake had the depth of 27.6 km. It’s size was ML1.4, so it was a small earthquake. I do not believe that this depth is a result of a error in the SIL system (can happen sometimes). A second earthquake took place at 10:13 UTC, its size was ML1.6 with the depth of 1.6 km.

Whatever that is happening in Hofsjökull volcano is worth watching. Even if it not going to erupt just yet. It is also my opinion that Hofsjökull volcano is not part of Western Iceland Rift Zone (pdf). But its is the most southern part of a failed rift zone often called Skagafjörður volcanic zone (pdf). It is a failed volcanic zone that is mostly extinct, only Hofsjökull volcano and Kerlingarfjöll volcano remain active in that volcanic zone at the most southern end of it.

Other information.

Jarðhiti í Hofsjökli (Tímarit.is, Icelandic, 1996, pdf) – Article with picture of where the hydrothermal vent was found in Hofsjökull glacier.
Hofsjökull (Wiki, english)

Text updated at 18:11 UTC on 6. April 2011. Minor fixes in the text.

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Overview of the earthquake activity in Grímsfjall volcano

Here is a short overview of the activity in Grímsfjall volcano in Week 08 and Week 13 for a comparison. A quick review of the earthquake data on the Icelandic Met Office web page suggests that the current path to a eruption started in Week 07.

It is clear on the pattern that has been evolving over the past four to five weeks where the eruption is most likely going to happen. That location is almost directly below the SIL station that Icelandic Met Office.


Week 08. Picture is from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office. Click on the picture to get full size.


Week 13. Picture is from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office. Click on the picture to get full size.

The evolving cluster of earthquakes can clearly be seen in this week overviews, and other in between them (Week 07 to week 13). It is clear that the magma has found a collection spot inside Grímsfjall volcano. But the question remains where it is going to break it self when a eruption starts. It is rather that question rather then when it happens, given the earthquake pattern that I am seeing coming from Grímsfjall volcano at current time.

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Two earthquakes in Grímsfjall volcano

This two earthquakes did happen in Grímsfjall volcano today. There signature clearly shows that they are created by magma breaking the crust. The background noise (SIL tremor plot) in Grímsfjall volcano also appears to have changed following this two earthquakes. I am not sure why that it. But this two earthquakes might be a pre-sequence to a eruption in Grímsfjall volcano. But it is hard to be sure on that at this moment. But I am sure that it is getting shorter to a eruption in Grímsfjall volcano.


Unallocated earthquake, most likely from Grímsfjall volcano. This picture is released under Creative Commons Licence. See link at top for more information.


Unallocated earthquake. This earthquake is from Grímsfjall volcano. The automatic size is ML2.9. With the depth of 1.1 km. This picture is released under Creative Commons Licence. See link at top for more information.

If anything more interesting happens at Grímsfjall volcano. I am going to post more information about it soon after it happens.

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A short history of volcano eruptions in Iceland

Here is a short list of known eruptions in Iceland since the year 900 (or around that time). There might be missing eruptions because of lack of historical data. This list might not be completed from the reference that I am using.

Year of eruption

Year ~870. Ash and lava flow eruption in Vatnaöldum. Settlers ash layer is created in Iceland.

Year ~900. Creation of a lava field named Afstapahraun.

Year ~900 – ?. Somewhere in Vatnajökull glacier.

Year ~900. Krafla volcano erupts.

Year ~900. Hallmundarhraun lava field is created.

Year ~900. Rauðhálshraun lava field in Hnappadal is created.

Year ~905 – ?. Somewhere in Vatnajökull glacier.

Year ~920. Somwhere on the Reykjanes ridge. Location is unknown. But a ash layer is known from this eruption.

Year ~920. Katla volcano eruption. Ash layer named Katla-R.

Year ~934. Katla volcano creates Eldgjá volcano fissure. Lava flow from Eldgjá volcano fissure flows over Álftaver, Meðalland and Landbrot. Mýrdalssandur is sad to have been created in this eruption by a big flood from Mýrdalsjökuli following this eruption.

Year ~940. In Vatnajökull glacier or in Veiðivötnum. Ash from this eruption has been found in north-east Iceland.

Year 999 or 1000. Svínahraun lava field is created in a volcano eruption.

Year ~1000. Katla volcano eruption. Ash layer has been found. There is a written account of the flood that followed this eruption.

Year ~1060. Somewhere in Vatnajökli glacier.

Year 1104. Hekla volcano erupts it’s first documented eruption in Iceland. This eruptions sends ash to north and north-east. The valley of Þjórsárdalur is destroyed by volcano ash in this eruption.

Year 1151. Krýsuvík volcano erupts. This eruption creates the lava field Ögmundarhraun and Kapellahraun lava field. Trölladyngja is also created in this eruption.

Year 1158. Eruption in Hekla volcano.

Year ~1160. Somewhere in Vatnajökull glacier.

Year 1160 – 1180. Eruption on the Reykjanes Ridge. Two eruptions on the Reykjanes Ridge. Ash layer is known from this eruption.

Year 1179. Katla volcano eruption. Written accounts are unclear. But ash from this eruption has been found in Greenland glacier.

Year 1188 – ?. Rjúpnadyngjuhraun and Mávahlíðarhraun lava fields are created.

Year 1206. Hekla volcano erupts.

Year 1210 – 1211. Volcano eruption on the Reykjanes Ridge. Eldey is created in this eruption.

Year 1222. Hekla eruption.

Year 1223. Volcano eruption on the Reykjanes Ridge. Location unknown.

Year 1225. Volcano eruption on the Reykjanes Ridge. Location unknown.

Year 1226 – 1227. Several volcano eruptions on the Reykjanes. The following lava fields are belvied to have been created in this eruption, Younger Stampahraun, (Klofningahraun), Eldvarpahraun, Illahraun and Arnarseturshraun. At the same time a large ash eruption takes place at Reykjanestá. The middle age ash layer is created in this volcano eruption. This volcano eruption created a lot of problems for the local population.

Year 1231. Volcano eruption on the Reykjanes Ridge. Location unknown.

Year 1238. Volcano eruption on the Reykjanes Ridge. Location unknown.

Year 1240. Volcano eruption on the Reykjanes Ridge. Location unknown.

Year 1245. Volcano eruption in Katla volcano. This eruptions comes up at Sólheimajökli. Flood follows this eruption.

Year 1262. Volcano eruption in Katla volcano. This eruption is in Sólheimajökli. It creates a flood and is followed by a heavy ash fall.

Year 1300 – 1301. Hekla volcano eruption. A lot of ash fall in Skagafjöður, a famine followed this eruption due to ash fall.

Year 1311. A volcano eruption in Katla volcano. Heavy ash fall in east of Iceland (austfjörðum). A big flood followed this eruption, it was most likely on Mýrdalssandi. But written accounts are unclear and unreliable on what did happen.The following year was followed by a famine with death of both people and animals due too volcano ash.

Year 1332. A volcano eruption in Vatnajökli glacier. Most likely in Grímsfjall volcano.

Year 1340 – ?. Eruption in Brennisteinsfjöllum volcano. But no lava field from 14th century have been found however.

Year 1341. Hekla volcano eruption. Heavy ash fall. The ash did go to Borgarfjörð and Akranes. A lot of animal did die. Many farms in Rangárvöllum where abandoned following this eruption.

Year 1341 – ?. Grímsfjall volcano erupts.

Year 1354 – ?. Grímsfjall volcano erupts.

Year 1357. A large eruption in Katla volcano. A lot of damage.

Year 1362. A large eruption in Öræfajökull volcano. It did destory the county of Litla-Hérað and most likely all people how lived there did die. Most of the ash fall was into the ocean. But some of it did go to Hornafirði and in Lónshverfi. A glacier flood did go down Skeiðársand and out to the ocean.

Year 1372. North-west of Grímsey.

Year 1389 – 1390. Around Hekla volcano. Several farms did go under lava field in this eruption.

Year 1416. Eruption in Katla volcano.

Year 1422. Eruption somewhere off the Reykjanes. Creates a island that lasts for few years.

Year 1440. Eruption in or around Hekla volcano.

Year 1477. Volcano eruption on a long fissure in Veiðivötnum lakes and it reaches the western part of Vatnajökull glacier.

Year ~1480 – ~1500. Katla volcano has eruption. Few written accounts of this eruption.

Year ~1500. Somewhere in Vatnajökli glacier.

Year 1510. A large eruption in Hekla volcano. This eruption creates the largest known historical lava field from Hekla volcano. A heavy ash fall too the south takes place. A lot of destruction in Rangarvallársýsla follows it.

Year 1554. A eruption South-West of Hekla volcano. This eruption lasts about six weeks. Created craters called Rauðubjallar and from them a lava field called Pálssteinshraun.

Year 1580. Katla volcano erupts.

Year ~1582. Somewhere close to Eldey is a eruption.

Year 1597. A eruption in Hekla volcano started 3. January. Ash fall did happen but did not create a lot of damage.

Year 1598. Eruption in Grímsfjall volcano.

Year 1603. Eruption in Grímsfjall volcano.

Year 1612. Eruption in Katla volcano and Eyjafjallajökull volcano. A volcano eruption did start on 12. October in Katla volcano. But it unclear when the eruption did start in Eyjafjallajökull volcano.

Year 1619. Eruption in Grímsfjalla volcano.

Year 1625. Eruption starts in Katla volcano. The eruption started on the 2. September and it ended on the 25. September. This was a large eruption that did destroy 25 farms. Most the ash fall was to the east in this eruption. First report about volcano eruption is written in about this eruption.

Year 1629. Eruption in Grímsfjall volcano.

Year 1636 – 1637. Eruption in Hekla volcano starts 8. May and is ongoing for about one year. Little ash and little damage from this volcano eruption.

Year 1637 – 1638. Eruption somewhere in the neighbourhood of Vestmannaeyjar volcano.

Year 1638. Eruption in Grímsfjall volcano.

Year 1655. Eruption somewhere in Vatnajökull glacier. Most likely in Kverkfjöllum volcano. A large glacier flood took place in Jökulsá á fjöllum.

Year 1659. Eruption in Grímsfjall volcano.

Year 1660 – 1661. Katla volcano eruption did start on the 3. November and lasted over the new year. Not a lot of ash fall. But a large glacier flood. It did destroy the farm called Höfðabrekka.

Year 1681. Somewhere in Vatnajökuli glacier.

Year 1684 – 1685. Eruption in Grímsfjall volcano. A large glacier flood in Jökulsá á fjöllum. One man did die along with large number of livestock.

Year 1693. Volcano eruption in Hekla volcano. This eruption did start on the 13. February. A lot of the ash did go to north-west. The ash fall did create a heavy damage in the nearby area.

Year 1693. Katla volcano erupts.

Year 1697. Eruption somewhere in Vatnajökull volcano glacier.

Year 1702. Eruption somewhere in Vatnajökull volcano glacier.

Year 1706. Eruption somewhere in Vatnajökull volcano glacier.

Year 1711 – 1712. Eruption in Kverkfjöll volcano.

Year 1721. Eruption in Katla volcano. Heavy ash fall, volume of ash is estimated 1 km³ and large glacier flood follows this eruption.

Year 1724 – 1729. Krafla volcano eruption. This eruption creates the crater Víti when lava did flow into Mývatn.

Year 1725. Eruption somewhere in Vatnajökull volcano glacier.

Year 1725. Eruption takes place south-east of Hekla volcano.

Year 1726. Eruption somewhere in Vatnajökull volcano glacier.

Year 1727. Volcano eruption in Öræfajökull volcano. Three people did die in this eruption.

Year 1729. Volcano eruption in Kverkfjöll volcano.

Year 1746. Volcano eruption in Krafla volcano. Only one eruption documented.

Year 1753. Eruption takes place south-west of Grímsfjall volcano.

Year 1755 – 1756. A eruption starts in Katla volcano on the 17. October. A heavy ash fall that is estimated to have been 1,5 km³ drifts to the north-east and creates heavy damage in it’s path. A large glacier flood goes down Mýrdalssand. It flows mostly west of Hafursey. Two men die due to lightning strike. About 50 farms where abounded temporary due to this eruption.

Year 1766. Eruption in the western part of Vatnajökull glacier. Most likely in Bárðarbunga volcano.

Year 1766. Volcano eruption in Hekla volcano. The ash cloud drifts to Húnaþings counties and Skagafjarðar. Ten farms where abandoned following this eruption due to the ash cloud.

Year 1774. Volcano eruption in Grímsfjall volcano.

Year 1783. Eruption on the Reykjanes Ridge. Creates a new island named Nýey. It is not far from Eldey. But it disappears soon after it’s creation.

Year 1783 – 1784. Skaftáreldar take place. A long with a eruption in Grímsfjall volcano. Lava flows over a area of the size 580 km². Volcano gasses and did create famine and shortage of green grass for live stock around most of Iceland. Effects of this eruption was felt over in Europe and most of northern hemisphere.

Year 1797. Volcano eruption in Grímsfjall volcano.

Year 1807. Volcano eruption in Grímsfjall volcano.

Year 1816. Volcano eruption in Grímsfjall volcano.

Year 1821. Volcano eruption in Katla volcano.

Year 1821 – 1823. Volcano eruption in Eyjafjallajökull volcano. This eruption started on the 19. December and was mostly ash fall. A glacier flood did go down Markarfljót.

Year 1823. Eruption somewhere in Vatnajökull glacier.

Year 1830. Eruption takes place somewhere in the area of Eldeyjarboða.

Year 1838. Eruption in Grímsfjall volcano.

Year 1845 – 1846. Eruption starts in Hekla volcano on the 2. September. A lava flow covers 25 km² area. Heavy ash fall follows this eruption. The farm Næfurholt was moved following this eruption.

Year 1854. Eruption in Grímsfjall volcano.

Year 1860. Eruption in Katla volcano. This eruption is small.

Year 1861. Most likely a eruption in Grímsfjall volcano that year. But it is uncertain.

Year 1862 – 1864. A eruption starts on the 15 km long fissure north of Tungnaárjökuls. It creates a crater rows called Tröllagígar and a lava field called Tröllahraun. The volcano responsible for this eruption is Bárðarbunga volcano.

Year 1867. Volcano eruption in Grímsfjall volcano.

Year 1867 – 1868. Volcano eruption around or creates Mánareyjar.

Year 1872. Eruption somewhere in Vatnajökull glacier.

Year 1873. Volcano eruption in Grímsfjall volcano.

Year 1874. Askja volcano erupts. Eruption may have started in February, when steam clouds where first seen.

Year 1875. Askja volcano erupts. A lava eruption did start on 3. January. A caldera starts to form later in January following this eruption.

Year 1875. A 25 km long fissure opens 18. February and lasted until middle of August. This is believed to be a dike intrusion from Askja volcano that did get up to the surface.

Year 1875. The largest eruption in history of Iceland started on the 28. March and lasted for about 8 hours. In this eruption the crater Víti erupted and other caters. There was a heavy ash fall in east of Iceland. This did destroy many farms in the east of Iceland. The Askja lake was created in this eruption. Many other eruption where documented in the following months.

Year 1876. The eruption from Askja volcano is believed to have ended in that year.

Year 1876. Eruption somewhere in Vatnajökli glacier.

Year 1878. Eruption in Krakártindur east of Hekla volcano.

Year 1879. Eruption close to Geirfulgasker.

Year 1883. Volcano eruption in Grímsfjall volcano.

Year 1884. Somewhere around Eldey. Poorly documented.

Year 1885. Most likely a eruption in Grímsfjall volcano. But it is poorly documented.

Year 1887. Eruption in Grímsfjall volcano.

Year 1889. Eruption in Grímsfjall volcano.

Year 1892. Eruption in Grímsfjall volcano.

Year 1896. Eruption most likely south of Vestmannaeyjar volcano.

Year 1897. Eruption in Grímsfjall volcano.

Year December 1902 – June 1903. Eruption in Bárðarbunga volcano. Eruption possibly in Dyngjuháls, exact location is unknown.

Year 1902 – 1904. Eruption in Grímsfjall volcano.

Year 1905 – 1906. Eruption in Grímsfjall volcano.

Year 1908 – 1908. Eruption in Grímsfjall volcano.

Year 1910 June 18 – October 1910. Eruption in Loki-Fögrufjöll (Hamarinn volcano).

Year 1910. Eruption in Grímsfjall volcano. Ash fall is documented from June to November in east of Iceland.

Year 1913. Eruption east of Hekla volcano in a area named Mundafell / Lambafell.

Year 1918. Katla volcano erupts. This eruption started 12. October and did finish 5. November. The ash cloud did go up to 14,3 km high into the air. A large glacier flood did go down Mýrdalssand. People was in danger. A lot of live stock got lost.

Year 1921. Askja volcano. Small fissure eruption.

Year 1922. Askja volcano. Small fissure eruption.

Year 1922. Grímsfjall volcano started erupting in September. This eruption did finish in less then a month.

Year 1923. Askja volcano. Small fissure eruption.

Year 1923. Grímsfjall volcano eruption. Small eruption.

Year 1926. Askja volcano eruption. Creates a small island in Öskjuvatni lake.

Year 1926. Around Eldey. Boiling ocean reported for few hours.

Year 1927. Around Esjufjöll volcano. Minor eruption. A glacier flood from Breiðarmerkujökli glacier that killed one person.

Year 1929. Askja volcano eruption possible. But poorly documented and uncertain because of that.

Year 1929. Eruption in Kverkfjöll volcano. The volcano eruption was observed during the summer.

Year 1933. Minor eruption in Grímsfjall volcano.

Year 1934. Eruption started in the middle March and lasted until middle of April in Grímsfjall volcano.

Year 1938. Eruption in Grímsfjall volcano. Was on the north part of the caldera. But did not break trough the glacier ice.

Year 1941. Eruption might have taken place in Grímsfjall volcano.

Year 1945. Eruption might have taken place in Grímsfjall volcano.

Year 1947 – 1948. A eruption starts in Hekla volcano on the 29. March. The ash cloud goes up to 30 km. The ash cloud goes to the south. The lava flow had the size of 0,8 km³. Most of it did go the west and south-west from Axlargýg.

Year 1954. Possible eruption in Grímsfjall volcano.

Year 1955. Possible small eruption in Katla volcano. Small glacier flood from Mýrdalsjökli.

Year 1961. A fissure eruption started on the 26. October in Askja volcano on a 300 meter long fissure.

Year 1963 – 1967. Eruption in the Vestmannaeyjar volcano system. Surtsey island is formed south of Geirfulgaskeri. Few smaller island are also created. But disappear quickly.

Year 1970. Eruption in Hekla volcano started on 5. May. Most of the ash fall was to NNW and into Húnavatnssýslur. The eruption the mountain only lasted for few days. But the eruption in Skjólkvíum the eruption lasted for about two months.

Year 1973. A volcano eruption starts in Vestmanneyjar volcano. A 1600 meter long fissure opens close to the town of Vestmanneyjar. About the third of the town did go under lava and about 400 houses where destroyed. This created Eldfell and Heimaey did grow to the east.

Year 1975. Krafla volcano eruption starts on 20. December. A short fissure opens on close to Leirhnjúk.

Year 1977. Krafla volcano eruption starts on 27. April, it ends on 29. April.

Year 1977. Krafla volcano erupts. Eruption starts on 8. September, it ends on 9. September.

Year 1980. Krafla volcano erupts on 16. March.

Year 1980. Krafla volcano erupts. Volcano erupts starts on 10. July, it sends on 18. July.

Year 1980. Krafla volcano erupts. The eruption starts on 18. October and is to 23. October.

Year 1981. Krafla volcano erupts. The eruption starts on 30. January and it sends on 4. February.

Year 1981. Krafla volcano erupts. The eruption starts on 18. November. It ends on 23. November.

Year 1980 – 1981. Hekla volcano erupts. The eruption started on 17. August, it lasted until 20. August. The eruption did resume on the 9. April the year later (1981) and did most likely end on 18. April.

Year 1983. Eruption in Grímsfjall volcano in the end of May.

Year 1984. A most likely a minor eruption in Grímsfjall volcano.

Year 1984. Eruption in Krafla volcano. It starts on 4. September and it sends 18. September.

Year 1985. Most likely a minor eruption in Lokahrygg in Vatnajökli glacier. Harmonic tremor is recorded and a caldera forms in the glacier.

Year 1991. Eruption starts in Hekla volcano on the 17. January. The power of the eruption quickly vanish. One crater remains active until 17. March. Little ash was in this eruption. Considerable amount of lava did flow south of Hekla volcano.

Year 1996. Eruption on a fissure between Bárðarbunga volcano and Grímsfjall volcano. This eruption started on 30. September on a 4 to 5 km long fissure. This eruption lasted until 30. October. The earthquake swarm did indicate the dike intrusion from Bárðarbunga volcano. Water that was melted in this eruption did flow to Grímsvatna in Grímsfjall volcano. The drain did happen on 5. November.

Year 1998. Volcano eruption in Grímsfjall volcano did start on 18. December. It lasted until 28. December.

Year 1999. Small volcano eruption takes place in Sólheimajökli glacier in the Katla volcano. Small glacier flood follows. The eruption does not break the surface of the glacier ice. This happens on 17. July. Earthquake swarm follows this event with largest earthquakes that are up to ML3.0 in size. Harmonic tremor is seen on seismometers around Katla volcano.

Year 2000. Eruption did start in Hekla volcano on the 26. February. It lasted until 8. March. Little ash did follow this eruption. Lava flow was not considerable large.

Year 2004. Eruption did start in Grímsfjall volcano on 4. November.

Year 2010. Eruption starts in Eyjafjallajökull volcano after a large earthquake swarm in it. The first phase of the eruption takes place in Fimmvörðuhálsi when a eruption starts there on 20. March. A eruption starts in the main crater on Eyjafjallajökull volcano on 14. April. A ash clouds follows it along with a glacier flood that goes down Markarfljót. Some damage takes place in this eruption the nearby area of Eyjafjallajökull volcano.

Year 2011. Largest eruption in 140 years Grímsfjall volcano start on May 21. It ended on May 25. The ash cloud coming from the eruption was the largest one in the past 140 years from Grímsfjall volcano. No glacier flood did take place in this eruption. The eruption started around 17:30 UTC. But the first steam cloud was not observed until around 18:32 UTC. The ash cloud did reach the hight of 20 km. But did soon drop down to 10 km. Three days after the eruption did start it did loose power at fast rate and was over on May 25.

Year 2011: Katla volcano had a subglacier eruption in July. This is the second eruption of the year 2011 in Iceland. A glacier flood followed this minor eruption of Katla volcano. The eruption started on 8th of July and ended on 9th July.

Year 2011: Hamarinn volcano might have (most likely) had a eruption week after Katla volcano. Glacier flood followed this minor eruption of Hamarinn volcano. The eruption ended 13 July. Total eruption time was around 12 to 14 hours.

Year 2014.

Bárðarbunga volcano

  • Two eruptions in the period of 16 – 22-August-2014. Exact time and date not known at the moment. Each eruption lasted for up to 24 hours at most.
  • Eruption 23-August-2014 under the glacier. Lasted for ~6 hours.
  • Eruption 29-August-2014 in Holuhraun. Lasted for ~4 hours.
  • Eruption 31-August-2014, it ended on 27-Februar-2015. It lasted for almost 6 months.
  • It is not clear how many minor eruptions have taken place under the glacier. Only documented eruptions are mentioned.

Year 2017

Katla volcano.
Start date: 29-July
End date: 29-July

A minor eruption took place in Katla volcano during the night of 29-July. It only lasted for 2 to 3 hours and was not visible and did not break trough the glacier. This eruption was only observed on harmonic tremor data from Icelandic Met office.


The minor eruption in Katla volcano as it appeared on harmonic tremor data on Icelandic Met Office SIL station. Copyright of this image belongs to Icelandic Met Office.

Before and after this even a small glacier flood appeared in Múlakvísl glacier river that comes from Mýrdalsjökull glacier. That glacier flood ended in the early mornings of 30-July-2017.
——-

This is the list of eruptions so far. It is not free of errors or typos. I am also going to update this list on a later date if I have to. As it is incomplete in regards to number of volcanoes mentioned in him.

Reference.

Eldgosaannáll Íslands (Wiki, Icelandic)
2010 eruptions of Eyjafjallajökull (Wiki)
Ármann Höskuldsson. „Hvert er öflugasta eldgos á Íslandi sem vitað er um?“. Vísindavefurinn 15.10.2010. http://visindavefur.is/?id=57031. (Skoðað 3.4.2011). (Icelandic)

Text is updated at 01:21 UTC on 4. April 2011. Error corrections to the list.
Text updated at 28. June 2011 at 22:34 UTC. Added Grímsfjall volcano eruption to the list.
Text updated at 28 September, 2011 at 12:56 UTC. Added Katla volcano eruption and Hamarinn volcano possible eruption to the list.
Article updated on 24-January-2015 at 00:57 UTC.
Article updated on 03-March-2015 at 15:14 UTC.
Article updated on 10-January-2016 at 19:19 UTC.
Article updated on 04-March-2016 at 03:00 UTC.
Article updated on 04-March-2016 at 03:08 UTC.
Article updated on 30-July-2017 at 20:18 UTC.
Article updated on 3-March-2019 at 00:24 UTC.

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A short history of earthquake activity on South Icelandic Seismic Zone (SISZ)

Here is a short overview of the activity on the South Icelandic Seismic Zone (SISZ) since Icelanders started to document it’s activity history. The oldest record of a large earthquake on SISZ is from the year 1103. In most cases it is not clear how large earthquakes are. But it was not until early 20th century when recording of earthquakes started it became clear how big the earthquakes in SISZ can really be. The average break between earthquake swarms in SISZ is from 1 year and up to 90 years.

Earthquake year.

Year 1103. A earthquake hits SISZ. It is not documented where. But 11 people died in that earthquake.

Year 1169. A earthquake hits Grímsnes. Total death was 19 people.

Year 1182. A earthquake kills 11 people. It is unclear where this earthquake did happen and how big it was.

Year 1211. A earthquake collapses many houses and kills 18 people. This earthquake took place 7th July.

Year 1294. A eruption in Hekla volcano and it is followed by many large earthquakes in SISZ. The hydrothermal activity increased in this earthquakes due to the earthquakes. It is believed that Geysir did form in this earthquake swarm in SISZ.

Year 1308. A large earthquake hits. Many houses collapse. Six people did die.

Year 1311. A large earthquakes hit on 10th and 11th of January. A total of 18 houses collapsed and 16 people died in this earthquakes.

Year 1339. A large earthquakes hit on 22nd of May. Witness account says that people where not able to stand up during the earthquake. Most collapse of houses did happen in Flóa, Holtamannahrepp and in places between Þjórsá and Eystri Rangár. Rockfall was witnessed following this earthquakes. A hydrothermal activity appeared in a mountain named Henglafjöllum (at that time) where none had been before.

Year 1370. A large earthquake south of Ölfus. A total of 12 houses collapse and six people did die in this earthquake.

Year 1389. Large earthquakes take place. Increased hydrothermal activity in Geysir area. New hot spring forms in that area.

Year 1391. A large earthquake takes place south of Grímsnes, Flóa and Ölfus. A total of 14 houses collapse and some so badly that they where totally destroyed. Water did flow from the ground following this earthquake. Only few people did die. They where sad as poor and the number it is not sad how many they where.

The gap between 1391 and too the year 1546 is most likely due to loss of historical documents. Not because there was a lack of earthquakes in SISZ during that time.

Year 1546. A large earthquake happens in SISZ. He is mostly noted in Ölfusi. A unknown number of houses collapsed. Nobody did die in this earthquake.

Year 1581. Earthquake did hit SISZ on the 30th of May around 03:00 local time (04:00 GMT modern time ?). Many houses collapsed during this earthquakes. Many people did die in this earthquake. In one instance is a death of a woman and here two year old kid is documented to have happened during this earthquake. Unconfirmed news from that time period say that that nine people died for east part of south Iceland and a large cracks did form in the ground because of the earthquake.

Year 1613. A earthquake hits. Date is not documented. A “mountain” is sad to have collapsed on Skeiðum and something called “reiðningstorfa” was outside a house. It did vanish during the earthquake and was never seen again. For the record. I have no idea what “reiðningstorfa” is. So don’t even try to ask me on it. I have no clue what so ever about this.

Year 1618. A large earthquake swarm hit SISZ. Earthquake hit SISZ all hours of the day. In one earthquake four houses collapsed and there was a formation of cracks so big that people where not able to cross over them.

Year 1624. A swarm of earthquake took place. Two houses collapsed. Human fatalities are not documented.

Year 1630. The winter that year a total of three earthquakes did happen. It did kill six people and collapsed unknown number of houses. The strongest earthquake took place on the 21st of February. A new fissures and cracks did form in the ground. The Geysir hydrothermal area did see large changes. New hot springs formed while others did dry up. Close to Skálhot fissures did open that both people and animals did fall into and die. They where also sad impossible to cross over.

Year 1633. Earthquake swarm hits SISZ,. Houses collapse in Ölfusi. Nothing more is documented.

Year 1657. A earthquake swarm both on SISZ and western part of Iceland (?). Two houses collapsed in this earthquake. But no human died in this earthquake swarm. On the 16th of March a earthquake did happen in Fljótshlíð and it did collapse many houses.

Year 1658. Earthquake swarm took place there between second and third day of Easter that year.

Year 1663. Many earthquakes in Reykjanes Peninsula did destroy many houses. Water levels in Kleifarvatn did drop. The water did flow into fissures that formed during the earthquakes. The water level dropped 300 feets. So that was once under water was now on dry land.

Year 1671. A earthquakes took place during the summer in Grímsnes and Ölfusi. But it is not documented if any damage took place during this earthquake swarm.

Year 1706. Large earthquakes take place this year. The first earthquakes takes place on the 28th of January. But the most earthquake takes place on the 20th of April when 24 houses collapsed. At least one person did die during this earthquake swarm. A loss was in live stock that did die during this earthquake swarm. This earthquake swarm lasted until spring. But was least noticed in western part of SISZ.

Year 1732. On the 7th of September a large earthquake took place in the area of Rangárvellir. This earthquake did damage 40 houses and 11 did collapse in the earthquake. Four people got hurt. But nobody did die during this earthquake.

Year 1734. On the 21th of March a large earthquake did take place. In Árnessýslu a total of 30 houses collapsed and 60 to 70 houses got damaged. The number of people how did die was 7 to 8.

Year 1749. A large earthquakes did happen in Ölfusi. There was a damage to houses. But none of them collapsed. But the base of one house did get lowered about 120 cm.

Year 1752. Earthquake swarm takes place in Ölfusi. It did collapse 11 houses and maybe one church.

Year 1754. A large earthquakes takes place in Krísuvík. It created a large hot spring. It was 6 faðmar wide and 3 faðmar deep (I have no idea what that is in the modern measurements).

Year 1784. This year one of the largest earthquake swarm in Iceland history took place on the 14th and 16th of August. It is believed that about 1900 houses where damaged or destroyed. The most damage was in the areas of Árnessýslu and Rangárvallarsýslu. Due this earthquake a lot of people lost there homes and had to spend the winter in a make shift houses made out of dirt or other poor building material, some people did try to repair there houses and live in them over the winter.

Year 1789. A lot of earthquakes where in Árnessýslu on 10th of June. This was followed by more earthquake activity a week later with earthquake being felt every 10 minute or less. A lot of new fissures and cracks did open up in Thingvellir following this earthquake swarm. Also in this earthquake swarm a lot of rock did fall out in Thingvellir and Almannagjá. Area in Almannagjá did become flooded (not sad what did flood it). In this area land did drop about 60 cm in some areas.

Year 1808. Strong earthquake in the SISZ. Did change hot springs and hydrothermal areas. Nothing more was reported on this earthquake that I know of.

Year 1828. Strong earthquake took place in Fljótshlíð. Most damage was in Fljótshlíð where 8 houses collapsed. One child did die because of lack of attention during this earthquakes.

Year 1829. On 21st of February a strong earthquake swarm did happen close to Hekla volcano. But the earthquake swarm was strongest closest to Hekla volcano. That area also did suffer the most damage. Where six to seven houses did suffer some damage.

Year 1896. One of the stronger earthquakes took place took place on the 26nd August that year. The first earthquake was the strongest and created a massive damage in the area of Árnes and Rangarvallarsýslum. It left many people homeless and there winter food for them selfs and winter saving of grass (what is that called in english?) for livestock. On the 27nd of August a second earthquake did happen. It epicentre was located close to the first one. The third earthquake did happen on 5th September in the area of Skeiðum. The fourth earthquake did take place on 6th September in the area of Ölfusi. The fifth and final did happen on the 10th of September, it’s location was in the area of Gaulverjarbæjarhreppi east of Selfoss. In this earthquakes about 3700 house and farms did collapse or suffer damage in this earthquake and three people did die.

Year 1912. A strong earthquake took place in the area of Hekla volcano. The size of that earthquake is estimated around M7.0. Around 30 houses got damage in a area from Þjórsá to Eyjafjallajökull volcano. One person did die, it was a child that got hit by a falling support beam (wood) in a house. It was in it’s mother arm when it did happen. The child is sad to have died instantly.

Year 2000. Two earthquakes did happen on SISZ that year. The first one was on 17th of June. It size was recorded Ms6.6. It did create a lot of damage all over SISZ. With many houses suffering heavy damage. The second major earthquake did happen on 21st of June. It size was Ms6.5 and it was a little bit more west then the first earthquake did happen. Over thousand smaller aftershocks took place following the first earthquake. Following this earthquake a earthquake swarm did start in Krísuvík, it got started with a earthquakes that where in the size of Mb5.5 to Mw6.0. But it is clear from the data that was collected that the bedrock in this area was already on the breaking point. The first earthquake that did happen on SISZ did trigger those earthquakes. The fault lines responsible for the earthquake where about 10 km long at the depth of about 5 to 9 km.

Science paper on the SISZ earthquake of the year 2000.
The June 2000 earthquake sequence in South Iceland (Icelandic Met Office, English)


Week 24 of the year 2000. Shows the aftershock pattern after the strong earthquake that year. Copyright of this picture belongs to Icelandic Met Office. It is from there web site.


Week 25 of the year 2000. Shows the evolving aftershock pattern after the second strong earthquake on the SISZ that year. Copyright of this picture belongs to Icelandic Met Office. It is from there web site.


High detail picture of the earthquake activity area in SISZ of the year 2000. Copyright of this picture belongs to Icelandic Met Office. It is from there web site.

Year 2008. On the 29th of May 2008 there was a earthquake with the size of Mw6.3 on the SISZ. It’s location was between Selfoss and Hveragerði towns. Both towns did suffer rather extensive damage following the earthquake, nobody did die and just minor injuries where reported. Before the large earthquake did hit a smaller earthquake with the size of ML3.2 did happen, along with a swarm of smaller earthquakes. Sadly I did miss that earthquake due to a loss of power at my apartment during that time. Lucky for me I did just discover that just before the large Mw6.3 did happen.

This earthquake was felt in Reykjavík and all around south and west Iceland. There are even report it was felt in Ísafjörður town. I did notice it at home as it moved stuff around in my apartment, but it did not knock everything down in my apartment at Hvammstangi town.

Waveform data that I did record of this earthquake.


Mosfellsbær geophone that I had connection too in the year 2008 (that station has now stopped operations). The waveform data shows that the station got saturated when the earthquake did happen. This picture is released under Creative Commons Licence (see top link for more details).


Hvammstangi geophone did record this earthquake clearly. But it did not saturate the geophone like in Mosfellsbær geophone. This picture is released under Creative Commons Licence (see top link for more details).


Map of Iceland showing the area of the main activity where the Mw6.3 earthquake did happen and the large view of the aftershocks that did follow it. This is from Week 22 in 2008. Copyright of this picture belongs to Icelandic Met Office. It is from there web site.


Close up map of the activity following this earthquake. The fault line is clear on this map, as the aftershocks arrange them self clearly alongside it. This is from Week 22 in 2008. Copyright of this picture belongs to Icelandic Met Office. It is from there web site.


A detailed map of estimated epicentre of the earthquake, the pre-earthquake and how the crust did break up in this area. The fault line was about 12 km long this time around. This is from Week 22 in 2008. Copyright of this picture belongs to Icelandic Met Office. It is from there web site.

Here is a scientific paper on the SISZ 2008 earthquake. With all the details that are important when this type of earthquake happens in Iceland.

This is the short overview of activity in SISZ over the past 1000 years or so. It is clear that SISZ is going to have large earthquakes in the future. But when is always a good question. Like volcanoes it is impossible to know when a large earthquake happens in SISZ. But it is going to happen one day. You can be sure of that.

Reference

Nánar um Suðurlandsskjálftann. (This article is mostly based on this one. It is in Icelandic.)
Suðurlandsskjálfti (Wiki, Icelandic)
2000 Iceland earthquake (Wiki, english)
2008 Iceland earthquake (Wiki, english)

Sigurður Steinþórsson. „Hvenær kemur Suðurlandsskjálftinn?“. Vísindavefurinn 10.4.2003. http://visindavefur.is/?id=3326. (Skoðað 2.4.2011). (Icelandic)

Text updated at 1539 CEST on 3 April 2011. Minor text fixes.

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Asking for donations again because of income problem

As I can’t afford living in Denmark under the current circumstances due to low income, I am going to need your help (my readers) while I have to live here. But I am going to move back to Iceland in early June. Until that happens I have to make it trough April and May here in Denmark. But I do not know how May is going to turn out, because then the bill for the electric is going to come. I think that it is going to be high as electricity is expensive here in Denmark.

When all bills have been paid this month. I am going to have ~20.000 ISK left. But that is ~123€, ~174$ and ~917 DKK to live off the entire April here in Denmark. But I don’t think that can be done. The current status is a little bit better then what did happen in March. But the difference is not a big one.

Thanks for the support and the help.

Text updated at 15:41 CEST on 1. April 2011. Title updated and minor changes to the text.

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More on the Almannagjá fissure depth increase (Thingvellir)

The evening news on Rúv did show video of the fissure in Thingvellir. The fissure it self appears to be a extension of the current fissure named Almannagjá. That fissure is old. But this formation appears to be fresh. But it hard to know for sure how long it is since it was created. But the road has been there since the late 19th century. One of the ideas why this happened is that there is a connection with this fissure creation and the earthquakes in the SISZ in the year 2000 and 2008. But that however is unproven idea at this point.

Other then this I have not seen or got a lot of information about this fissure.

Here is a video of this fissure in the Rúv news at 19:00 UTC.

More information on Thingvellir and it’s geology.

Geology and tectonics of Þingvellir

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A new fissure starts to form in Thingvellir National Park (Almannagjá)

According to a news on Rúv. A new fissure has opened in south part of Almannagjá. It is not clear when this fissure started to form, but it looks to have formed in rather recent time (years?). But this fissure was discovered after a snow and frost started to thaw out of the ground in the last few weeks. This new fissure is about 10 to 14 meters deep and is under the middle of the walking path that is in this area. It has now been closed for safety reasons. Tourists and people how are travelling this area of Thingvellir are asked to respect the travel ban in this area. But this is a deep fissure and it is unmarked and dangerous.

This area is in part of the Hengill volcano fissure swarm. But it on the north-east edge of the end of that fissure swarm that extends from Hengill volcano.

News about this fissure formation. With picture. Use Google Translate with care. After all, it doesn’t understand Icelandic.

Djúp sprunga fannst undir göngustíg (Rúv, Icelandic)
Djúp sprunga myndast í Almannagjá (DV, Icelandic)

Updated at 15:57 CEST on the 31. March 2011. New newslink added.

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Changes in Grímsfjall volcano

Few days ago changes started to happen in Grímsfjall volcano. It is hard to describe this changes. But they appears to be changes in harmonic tremor levels in Grímsfjall volcano. But they appears to be above background levels and the reason why that is a bit unclear at the moment, but I do not think that this is ice movement as I did think it was first. As this has been lasting for too long. Following this has been a slow increase in earthquakes in and around Grímsfjall volcano. This earthquakes don’t appear on the automatic SIL system, even if they are up to ML2.0 in size. This suggest that there origin is from magma movements, not tectonics one (tectonics earthquakes also happen there).

So far nothing suggest that a eruption is immanent. But that can change without any warning. As Grímsfjall volcano is known to start a eruption with no warning at all.


Harmonic tremor levels in Grímsfjall volcano on 30th March 2011. Picture is from around 17:30 UTC. Copyright of this picture belongs to Icelandic Met Office. The picture is from there web site.


Earthquakes in Grímsfjall volcano on 30th March 2011. Picture is from 17:30 UTC. Copyright of this picture belongs to Icelandic Met Office. The picture is from there web site.

All that can be done for now is to wait and see what happens. But my opinion is that something is up in Grímsfjall volcano. But what that is remains unclear at the moment.

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A minor earthquake swarm in Krýsuvík volcano

At 20:41 UTC (28. March 2011) a minor earthquake swarm did start in Krýsuvík volcano. This earthquake swarm is small and no earthquake has gone over the size ML2.0. All the earthquakes recorded so far have rather poor quality in the SIL system and therefore it is not possible to say for sure what the the depth of this earthquakes is. But the assumed depth of the earthquakes in this earthquake swarm is around 5 km.

It remains to be seen if this earthquake swarm grows larger or not. But so far it remains small in both number of earthquakes and size.