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Interesting earthquake activity in Tungnafellsjökull volcano

This is not the most known volcano in Iceland, it also has not erupted in the last 10.000 years at least. Normally this volcano does not have any earthquakes and it remains really quiet. Last major earthquake activity was in the year 1996 in relation to the activity in Bárðarbunga volcano and in Grímsfjall volcano that year. This volcano is named Tungnafellsjökull. It is a small volcano compared to other volcanoes in the area. During the past few days there have been several interesting earthquakes in Tungnafellsjökull volcano. They are small, around ML1.6 the largest ones. But they do have the depth of 10 to 12 km. That is what makes this earthquake activity interesting. Since this suggest that magma might be pushing into the volcano. However at this point in time, there is nothing to suggest an eruption is even close to start there. But with all long dormant volcanoes, nobody never knows what can happen next in them.


The earthquake activity in Tungnafellsjökull volcano. The volcano is located NW of Vatnajökull glacier. Copyright of this picture belongs to Iceland Meteorological Office.

Following the later earthquake today. This activity started on Skrokkalda SIL station. But this might be due to activity in Hamarinn volcano (Loki-Fögrufjöll at GVP). Not Tungnafellsjökull volcano.


The odd tremor activity on Skrokkalda SIL station. I do not yet have any explanation for this activity. Note that Skrokkalda SIL station is on top of a volcano (not on GVP list, but geological maps made in Iceland), named Skrokkalda, it also has not erupted in historical times to my knowledge. Copyright of this picture belongs to Iceland Meteorological Office.

What happens next in Tungnafellsjökull volcano is impossible to know. But it is most likely going to do what it has been doing for the past 10.000 years. A lot of nothing.

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Overview of current events in Askja volcano

The current events in Askja volcano started in Week 9 of the year 2010. Before that, Askja volcano has been showing signs of change since the year 2007 at least. In the year 2010, Week 9 a earthquake swarm was recorded by Iceland Meteorological Office. Most of the earthquakes where at around 20 km depth, and it was followed by considerable amount of harmonic tremor activity. I did know about it at the time, but I did think it would be at least 10 to 20 years until Askja volcano would not erupt. But this might have been a event in an series of event that started long time ago, without me knowing about it before (I am still checking data, it takes some time).


The earthquake activity in Askja volcano in Week 9 of the year 2010. Copyright of this picture belongs to Iceland Meteorological Office.

The image above clearly shows where magma was flowing into Askja volcano around 20 km depth. But they are to the north-east of Askja lake. The depth of this earthquakes was from 20 to 23 km.


Map of earthquake activity in Askja volcano. The green dots are earthquakes with a shallow depth, that is depth from 2 to 8 km. Yellow earthquakes have the depth of 12 to 30 km. This data is from the year 2007 at least. Copyright of this picture belongs to its owner (Janet Key).


The depth of the earthquakes in Askja volcano. Copyright of this picture belongs to its owner (Janet Key).


Depth of the earthquakes. This view shows also where the earthquakes are taking place in Askja volcano and close to it. Copyright of this picture belongs to its owner (Janet Key).

All of this map and charts are from this blog post here.


This is a heat camera image of Askja lake. Copyright of this picture belongs to Iceland Coast Guard, the image is from here.

Last year (2011) there was an dike intrusion in north part of Askja volcano. This dike intrusion was clear by a earthquakes that took place. But it stopped and has not shown any activity again in this area. As sometimes happens with dike intrusions. But this activity is an good sign that magma is now flowing into Askja volcano again. But over period of at least 10 to 20 years, it seems that magma has been flowing out of Askja volcano system. Where it has been going I have no idea. But some hypothesis suggests that it might be flowing into Krafla volcano. But there is no good data to support this hypothesis in partial.


Activity in Askja volcano in the year 2011. This activity took place on 05.05.2011 at 16:25 UTC. Copyright of this picture belongs to Iceland Meteorological Office.

At the moment there is nothing that suggest eruption is imminent. But current progress in Askja volcano is something to keep an watch on. But it is also clear that current status in Askja volcano is changing fast. So while there is nothing to suggest a eruption at the moment, it might change without warning in Askja volcano.

Pictures of Askja lake.

Askja lake 12 June 2011.
Picture of Askja lake (32 months ago according to flickr.)

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More on Askja lake sudden warming up

Few more news have appeared about the sudden warming of Askja volcano caldera lake. From what I this news say. It seems that this sudden melt of ice in Askja lake did start in beginning of March, by the end of March the lake had gone completely ice free. This is highly unusual and is not known to have happened before. This increase in hydro-thermal activity seems to be located at the bottom of the lake. But so far there is no new change around Askja lake. But it was reported yesterday that known hydro-thermal areas in Askja volcano where well active. It is now being reported that Askja lake got ice-free over period of two weeks so. But that is highly unusual and fast change in Askja lake.

Earthquake activity has not been above background level in Askja volcano so far. But this increase in hydro-thermal activity is interesting from geological point of view, and is the most clear sign that Askja volcano is preparing for a eruption. But there have been earthquakes taking place in Askja volcano. But as I sad yesterday. There have been few earthquakes in Askja volcano during past few months. Askja lake is about 1000 meters above the sea level. This means that once ice settles the lake in December it normally lasts until mid July. But the lake is self is normally up to 22C warm. So the warm increase

If anyone is going to Askja volcano. It is now official advice that people how are travelling in this area not to into Víti lake, or into Askja lake due to risk of dangerous gases that might be coming up from the ground. If you have no special reason going to Askja volcano, you should not go there at this point due to the changes in the volcano. As at this moment it is unknown what exactly is creating this changes in the Askja lake, and possibly nearby hydro-thermal areas.

University of Iceland and Iceland Meteorological Office are going to go after Easter and setup more monitoring hardware and run some test on what might be taking place in Askja volcano.

Update 1: Here is a youtube video by the user gummih that shows how fast Askja lake did thaw during middle of winter.

Icelandic news about this. Use Google translate to make sense of it.

Fylgst með framvindu mála í Öskju (mbl.is)
„Óeðlilegt ástand“ í Öskjuvatni (DV.is)
Fólk fari ekki að Öskjuvatni (mbl.is) – The news with the offical warning about going to Askja lake and Askja volcano.
Vara ferðafólk við Öskjuvatni og Víti (Rúv.is)
Almannavarnir: Ekki fara að Öskju (DV.is)
Óvenjulegt ástand við Öskju (Almannavarnir, Iceland Civil Emergency Authority)
Fólki bent á að fara ekki að Öskju (Vísir.is)

News in English about this

Photos: Iceless Iceland Volcano Lake Causes Speculation (icelandreview.com)

Blog post updated at 18:46 UTC on 04.04.2012.
Blog post updated at 19:12 UTC on 04.04.2012.
Blog post updated at 20:12 UTC on 04.04.2012.
Blog post updated at 01:28 UTC on 05.04.2012.

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Askja lake ice free during winter

It seems that Askja volcano is warming up. Literally. According to news on Morgunblaðið web site. The Askja volcano lake is now ice free. But that is highly unusual event. But normally during this time of year it is frozen over. In the news it is explained that this might be because the south wind in Iceland during the past few days, or the most likely second option. Askja volcano lake is now ice free because of more hydro-thermal activity in it. But that is seen as more likely option, as Mývatn lake, that is at considerable lower altitude is now frozen over. There was done a air survey with thermal cameras to see if there was any increased heat on the surface. So far that is not the case at the moment. But it might well be that the hydro-thermal areas under Askja lake are getting more active an warmer. At least that is the only explanation that makes logical sense to the scientists according to this news report. But while the surface activity is none. The chance is that at the bottom of the lake it is getting really hot, and that in turn warms up all the water mass in the Askja lake. But this means that the energy output from the hydro-thermal areas is already high. Even if it is not visible at the surface of the lake.

Askja lake is around 220 meters deep. It was formed in large eruption in the year 1875 (VEI=5). But that was an caldera formation event that took place. But where Askja lake is now, it used to have a mountain that was in decent high before it was blown up into the air. At current time there is no new hydro-thermal activity in Askja volcano (around the lake). Besides the one reported in Askja lake. But based on recorded history, that might change soon. But it seems that before an eruption in Askja volcano, hydro-thermal activity increases in Askja volcano. But that means new hot springs, geysers and such. With all associated dangers and smells from sulfur. At current time, there is no risk of imminent eruption. As the activity at this moment suggests this is just starting, a long more might need to happen before an eruption. But that might change without warning as always. Since all volcanoes are impossible to predict what happens in them. Askja volcano has been having slight increase in earthquake activity during past few months. That suggests new magma is flowing into Askja volcano. But that earthquake activity has somewhat stopped completely and activity has quieted down from what it was few months ago.

Update 1: Here is a new picture of Askja volcano. Taken by Ómar Ragnarsson retired news reporter from Iceland. He also has a new image from Kverkfjöll volcano here.

Update 2: Iceland Meteorological Office has issued a press release about Askja volcano. It says that Askja lake is now ice free (same as in other news). The coast guard did go to check Askja lake on 2nd April 2012 with thermal cameras. In that trip it was discovered that Askja lake is completely ice free with no floating ice in it. The known hydro-thermal areas that are known where well active according to IMO. But no new areas of hydro-thermal activity where spotted in this flight over Askja volcano. Iceland Meteorological Office is going to increase surveillance with Askja volcano and to watch for future progress on what might happen in Askja volcano in the future.

News about this in Icelandic. Use Google translate to scare the Easter Bunny.

Öskjuvatn íslaust með öllu (mbl.is)
Íslaust Öskjuvatn í mars (Vatnajökulsþjóðgarður)
Öskjuvatn íslaust (Iceland Meteorological Office)

New pictures of Askja lake are in both news. Showing it completely ice free during the winter. Pictures are taken on 18th and 27th of March. Iceland Meteorological Office has MODIS picture of Askja volcano that clearly shows how ice free Askja lake actually is.

Blog post updated at 01:32 UTC on 03.04.2012.
Blog post updated at 01:45 UTC on 03.04.2012.
Blog post updated at 16:32 UTC on 03.04.2012.
Blog post updated at 16:48 UTC on 03.04.2012.

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Minor earthquake activity in Iceland

During the past few weeks it has been quiet in Iceland. Really quiet, with almost nothing going on. It is still like that to some extent. So this is just a short overview of the small activity that has been taking place in Iceland during the past 48 hours or so.


The earthquake activity in Iceland during the past 48 hours. Copyright of this image belongs to Iceland Met Office.

The most activity in the last 48 hours have been on the Reykjanes and on TFZ. But there was an small earthquake swarm in each area. With earthquakes that did not get over ML2.5 in size so far. Two earthquakes where in Askja volcano. One in Grímsfjall volcano fissure system (maybe in Þórðarhyrna volcano).


Earthquake west of Hekla volcano, in the SISZ. This picture is released under Creative Common Licencee. See the licence page for more detail.

Katla volcano

During this winter. Katla volcano has been quiet. This is somewhat normal, as more snow means more ice-mass on top of the volcano. But now that has started to melt a little and that means less ice-mass on top of the volcano. That could mean more activity in Katla volcnao during the next few weeks. So far however the activity remains small and there are no special earthquakes to report.


Earthquake activity in Katla volcano, on this picture earthquake activity west of Hekla volcano can also been seen here. Copyright of this image belongs to Iceland Met Office.

The earthquakes west of Hekla volcano belong to the SISZ fault area. Not Hekla volcano it self. What is also interesting is the earthquake activity in south part of Katla volcano. In area outside of the glacier. This are small earthquakes, that do not appear on my geophone. Even if they are close to it. I am unsure what this means for the future. But it is worth keeping an eye on it.

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Grímsfjall volcano continues to prepare for a new eruption

As I did mention in a blog post from 16. January 2012. Grímsfjall volcano is preparing for a new eruption. That progress has not slowed down at all. I am rather sure that the eruption prepare progress in Grímsfjall volcano has sped up. But this is nothing confirmed at the moment. I am just noticing slow increase in earthquakes from Grímsfjall volcano.


Today’s activity in Grímsfjall volcano. Copyright of this picture belongs to Iceland Met Office.


Grímsfjall volcano activity in Week 11 2012. Copyright of this picture belongs to Iceland Met Office.


Grímsfjall volcano activity in Week 12 2012. Copyright of this picture belongs to Iceland Met Office.

It is impossible to know for sure when next eruption starts in Grímsfjall volcano. But at the current time, the clock is ticking down faster then it did before in my opinion. As is known from history. Grímsfjall volcano has erupted sometimes the year after. Even after a big eruption. As was the case last year (2011), when it had the largest eruption in 140 years.

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Pictures of a old volcano rift zone

Here is a picture of what remains of Snæfellsnes – Húnaþing Rift zone. But this rift zone was activity about 4 million years ago. I do not know why this part of the rift zone is visible. But it seems to have escaped glacier erosion during past 4 million years since it became extinct.


The visible part of the Snæfellsnes – Húnaþing rift zone that was active about 4 million years ago. The farm in this picture is called Bjarghús. This picture is released under Creative Common Licence. Jón Frímann Jónsson took this picture on 24.03.2012.


This is where the visible rift zone disappear back into the ground. Its visibility resumes at distance. This picture is released under Creative Common Licence. Jón Frímann Jónsson took this picture on 24.03.2012.


The Snæfellsnes – Húnaþing rift zone is number two on this picture. What can be seen above ground is just a small part of it. This picture has been released under public domain licence. See this web page here for more details. This picture is not 100% correct on the details on the rift zones in Iceland. But is a good start for it.

Older blog post about this area can be found here. I am not expecting any eruption in this area. But it is always a possibly of a volcanic cone popping up in area like this. As the closest volcanoes to this area are only at the distance of 80 to 90 km south of it. But that is the Langjökull volcano, in the north part of it.

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List of known eruptions in Grímsfjall volcano and connected volcanoes

Here is an list of eruptions in Grímsfjall volcano and Þórðarhyrna volcano based on data from Global Volcanism Program and documented eruptions. In most cases, eruptions that took place in the early 10 to 16th century are poorly documented if they where smaller eruptions. This even goes on somewhat into the 20th century.

Year ~8230BC +-50 years. Area of activity, unknown. Size VEI=6. Known as Saksunarvatn tephra layer. Dating done with Radiocarbon (corrected).

Year ~4550BC +-500 years. Area of activity, Laki. Size VEI=0. Dating method, Tephrochronology.

Year ~3550BC +-500 years. Area of activity, S of Þórðarhyrna. Dating method, Tephrochronology.

Year ~1950BC +-100 years. Size VEI=2 Area of activity, Raudholar and Brunuholar. Dating method, Tephrochronology

Year ~50BC. Size VEI=2. Area of activity, Halsagigur. Dating method, Tephrochronology

Year ~910AD. Area of activity, ?. Dating method, Tephrochronology.

Year ~960AD. Area of activity, ?. Dating method, Ice core.

Year ~1010. Area of activity, ?. Dating method, Ice core.

Year ~1060. Area of activity, ?. Dating method, Tephrochronology.

Year ~1090. Area of activity, ?. Dating method, Ice core.

Year ~1150. Area of activity, ?. Dating method, Ice core.

Year ~1190. Area of activity, ?. Dating method, Ice core.

Year 1230 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year 1270 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year 1290 +-10 years. Area of activity, ?. Dating method, Ice core.

Year 1310 +-10 years. Area of activity, ?. Dating method, Ice core.

Year 1332, November. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1341, May. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year ~1350. Area of activity, ?. Dating method, Ice core.

Year ~1354. Area of activity, ?. Dating method, historical documents.

Year 1369. Area of activity, ?. Dating method, Ice core.

Year 1370 +-10 years. Area of activity, ?. Dating method, Ice core.

Year 1390 +-10 years Area of activity, ?. Dating method, Ice core.

Year 1430 +-10 years. Area of activity, ?. Dating method, Ice core.

Year 1450 +-10 years. Area of activity, ?. Dating method, Ice core.

Year ~1469. Area of activity, ?. Dating method, Ice core.

Year 1470 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year ~1471. Area of activity, ?. Dating method, Ice core.

Year 1490 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year ~1500. Area of activity, ?. Dating method, Ice core.

Year ~1509. Area of activity, ?. Dating method, Ice core.

Year 1510 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year 1521 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year 1530 +- 10 years. Area of activity, ?. Dating method, Ice core.

Year 1598. November 7. Area of activity, ?. Size VEI=3?. Dating method, historical documents.

Year 1603. October 31. Area of activity, possibly Grímsvötn. It is unclear. Dating method, historical documents.

Year 1610. Area of activity, ?. Dating method, Ice core.

Year 1619. July 29. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year ~1622. Area of activity, ?. Dating method, Ice core.

Year 1629. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1632. Area of activity, ?. Dating method, Ice core.

Year 1638 February 24 +- 4 days. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1659 November. Area of activity, ?. Size VEI=?. Dating method, historical documents.

Year 1681 April 10. This might not be an eruption in Grímsfjall volcano.

Year 1684 November 5 +- 4 days. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1697. Area of activity, ?. Size VEI=?. Dating method, historical documents.

Year 1706 October 15 +- 45 days. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1716 October 6. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1725 February. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1730. Area of activity, ?. Size VEI=?. Dating method, historical documents.

Year 1753 October 15 +-45 days. Area of activity, ?. Size VEI=2?. Dating method, historical documents.

Year 1768. This eruption might not have taken place in Grímsfjall volcano.

Year 1774. Area of activity, ?. Size VEI=?. Dating method, historical documents.

Year 1783 to 1785 May. Stop date May 25 1785. Area of activity, Laki, Lakagígar. Size VEI=4+. Dating method, historical documents.

Year 1794. Eruption might not have been in Grímsfjall volcano. Somewhere in West Vatnajökull.

Year 1816 May. Area of activity, ?. Size VEI=?. Dating method, historical documents.

Year 1823 February 4 +-4 days. Area of activity, Grímsvötn-Þórðarhyrna. Size VEI=2. Dating method, historical documents.

Year 1838 June. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1854. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1861. This eruption is uncertain.

Year 1867 August 29. Area of activity, ?. Size VEI=1. Dating method, historical documents.

Year 1873 January 8, it ended in August. Area of activity, ?. Size VEI=4. Dating method, historical documents.

Year 1883 January 15, it ended in April 15 +-5 days. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1887 August 15, it ended in the year 1889. Area of activity, Þórðarhyrna. Size VEI=2. Dating method, historical documents.

Year 1891 November, it ended in March 16 1892. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1897. Location of this eruption in uncertain. Area of activity, ?. Size VEI=2. Dating method, ?.

Year 1902 December, this eruption ended in the year 1904 on 12 January. Area of activity, Grímsfjall and Þórðarhyrna. Size VEI=4. Dating method, historical documents.

Year 1910. Area of activity, ?. Size VEI=?. Dating method, ?.

Year 1919. This eruption is uncertain.

Year 1922 September 29 +-1 day. This eruption ended on October 23. Area of activity, ?. Size VEI=2. Dating method, historical documents.

Year 1933 November 29 +-1 day. This eruption ended on December 9 +-1 day. Area of activity, North of Grímsvötn Caldera. Size VEI=1. Dating method, historical documents.

Year 1934 March 30, this eruption ended on April 7 in the year 1934. Area of activity, Close to south caldera wall. Size VEI=2. Dating method, historical documents.

Year 1934. This eruption is uncertain. But it took somewhere in Vatnajökull glacier.

Years 1938 May. Area of activity, 8 km south of Svartibunki. Size VEI=1. Dating method, historical documents.

Uncertain eruptions the years 1939 June, 1941 April, 1945 September 25, possible VEI=1 eruption, 1948 February.

Year 1954 January 15 +-45 days. Area of activity, ?. Size VEI=1. Dating method, historical documents.

Year 1954 July, this eruption is uncertain. Area of activity, north and south part of the caldera. Size VEI=1?. Dating method, historical documents.

Year 1972 March. This eruption is uncertain.

Year 1983 May 28. This eruption ended on June 2. Area of activity, close to the south part of the caldera wall. Size VEI=2. Dating method, historical documents.

Year 1984 August 20 (or around that date). This eruption is uncertain.

Year 1996, September 30. This eruption ended on November 6. Area of activity, Gjálp fissure. Size VEI=3?. Dating method, historical documents.

Year 1998, December 18. This eruption ended on 28 December. Area of activity, South Caldera wall. Size VEI=3. Dating method, historical documents.

Year 2004 November 1. This eruption ended on November 4. Area of activity, South West and east sides of the caldera. Size VEI=3. Dating method, historical documents.

Year 2011, May 21. This eruption ended on May 30. Area of activity, South West part of the caldrea. Size VEI=3. Dating method, historical documents.

This is just short overview of the eruptions that have taken place in Grímsfjall volcano and in Þórðarhyrna volcano. It does not contain a lot of details on them. Please not that this blog post might contains errors. If you see them. Please comment on them and I am going to fix them soon as I can.

This blog post is going to be updated with time.

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Historical eruption of Grímsfjall volcano of the year 1783 to 1785

The year 1783 is something that is going to live in historical memory of the Icelandic people for long time to come. The historical memory of Icelanders still remember the eruption of Laki that took place 229 years ago. This eruption is among Iceland biggest eruption in historical times and since Iceland got populated around the year 600 (or around that time, according to new data). It is unclear when the exact eruption started in Grímsfjall volcano and in Þórðarhyrna volcano (a smaller volcano south-west of Grímsfjall volcano, it is inside Grímsfjall volcano fissure swarm). But what is known is that this eruption started sometimes in May.

The eruption started in Grímsfjall volcano it self, it is unclear where exactly it started. Creating a glacier flood that did go down Þjórsá that same month in some part. But was documented that Þjórsá was darker and had worse smell then normally and had more water in it. It was also documented that Skaftá did have more water in it and was darker and had bad smell early spring in Iceland (that means late April or early May). But the glacier flood that must have taken place after an eruption started are not well documented in history best to my knowledge. From what I can read it seems that the eruption of Grímsfjall volcano started in the main volcano (unknown where exactly). The years 1755 and to the year 1785 seems to have been extremely active in terms of volcano activity in Iceland. But that year there was also an eruption on the Reykjanes Ridge that created a short lived Island. It did however only last few months at the best. It is possible that the eruption on the Reykjanes Ridge was in the area of Eldey or close to it. But it is impossible to confirm it for sure.

It is not known when the actual eruption started in Grímsfjall volcano or in Þórðarhyrna volcano. But it has been assumed from what I can gather that Þrórðarhyrna volcano was also erupting during this eruption. But the reason for that might well be due to dike intrusions from Grímsfjall volcano might have started an eruption in Þórðarhyrna volcano. But best to my knowledge, there have not been many eruptions in Þórðarhyrna volcano since the eruption in the year 1783 (or around that time).

According to documented history, the fissure eruption started around 8. June 1783. This fissure eruption had growing earthquake swarms before it took place. This was due (but they did not know this at the time for obvious reasons). When the eruption started, it started with a large ash cloud that did go down Skaftárhrepp and nearby area. Following this ash cloud was a lot of gas pushing up with the erupted material. But blue haze was reported in historical documents about this eruption. The problem with the carbon-monoxide did not get any better . Given the year this did happen, there are holes in the event as they did happen. But by 12th of June 1783 the lava had already filled several canons at least and had already destroyed a lot of farmland and farms. But it is documented that lava bombs where known to have been found up to 112 km distance from the eruption. The total fissure length is around 25 km long. It is among Iceland longest eruption fissure in historical times. But Askja volcano had an fissure eruption that was around 20 km long in its eruption episode around the year 1875 to the year 1961, when it took a break that is continuing to this day.

Based on historical documents. It seems that this eruption had two phases. The the first one started with an eruption in the south part of what is now the eruption fissure of Laki. The second one was when eruption craters did open up north part of the fissure after several months of eruption on the south part of the eruption fissure. But by that time the eruption had already diminished in strength at the same time, or before that. It is hard to know from historical documentation what actually did happen at this time. But the eruption is believed to have stopped on 26 May 1785.

Many of the eruption craters did make ash, not lava. The ash layers from those craters where up to 2 meters thick at the distance of 500 meters in some areas. It is also believed that the eruption strokes from many of the craters where up to 800 to 1400 meters high when they where at the tallest. During this eruption there was a sour rain, along with other deadly effects that did follow this eruption. It did also happen during this eruption that many animals did die due to ash poisoning, and gas poisoning from the eruption. Just as humans did at this time. But at this time Iceland did not have any functional government that was able to handle this type of natural disaster. The amount of volcanic gases also had effects around northern hemisphere. But this effects did create huge problems in Europe, Canada, U.S and in Russia from best of my knowledge (it might however not be correct).

Many people might believe that after such a big eruption Grímsfjall volcano would stop for a long time. This was not the case. Only 22 years after the major eruption of the year 1783 to 1785 Grímsfjall volcano had an new eruption. This was smaller, only having the VEI scale of 2. But Laki eruption has the VEI scale of 4+. Before the Laki eruption, there had been an other eruption in the year 1774, but it was an minor VEI=2 eruption. Last eruption in Þórðarhyrna and Grímsfjall volcanoes was in the year 1902. That was an VEI=4 eruption that lasted from December 1902 and until January 1904.

For this reasons I classify Grímsfjall volcano (including also Þórðarhyrna volcano) one of the dangerous volcanoes in Iceland. I do think it might be even be more dangerous the Katla volcano all considered. But this is just my personal opinion and nothing else.

Based on following references

Skaftáreldar 1783 (Icelandic)
Grímsvötn (Icelandic)
The eruption that changed Iceland forever (BBC News)

Blog post updated at 01:49 UTC on 22.03.2012.

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Going back to being Iceland volcano and earthquake blog from midnight (21.03.2012)

One of the lessons in life is that something you do does not always work, this is what I learn from when it comes down it. Sometimes it does not work first time around, sometimes it does work second time around. Sometimes it just does not work at all. My change in focus on this blog falls into the last group. It does not seems to work in my opinion of my readers. While only few have expressed this opinion to me. I take it seriously. Based on the opinions that I have heard so far. I have come to the following conclusions and made this decision following it.

From midnight UTC time. This blog is going to be renamed back into being Iceland volcano and earthquake blog. This means my focus is only going to be Iceland and nothing else (well, maybe I make an exception or two if it something really interesting) . As has been told here in comments there are other bloggers how cover other parts of the world and do an good job of it.

So from midnight. This blog and the forum is going back to the name “Iceland volcano and earthquake blog”. This also covers the forum. But the change is going to be more dramatic there. As I am going to arrange it in accordance with this change. No posts are going to be deleted, but are going to move around a bit. No blog posts are going to be deleted from this blog do to this name change. It is part of history in my view.