Skaftárkatlar

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Skaftárkatlar
Sylgjökull Hamarskriki 1 Iceland.JPG
The Skaftárkatlar can be seen when you enlarge the picture (click!) As two depressions to the right (i.e. in the northeast) of Hamarskriki, the large rocky bay on Hamarinn, which extends into Vatnajökull.
Geographical location Iceland
Drain Skaftá
Data
Coordinates 64 ° 29 '25 "  N , 17 ° 31' 15"  W Coordinates: 64 ° 29 '25 "  N , 17 ° 31' 15"  W.
Skaftárkatlar (Iceland)
Skaftárkatlar
Altitude above sea level 1460  m

particularities

Subglacial lakes , volcano

The Skaftárkatlar is a volcanic high temperature area with subglacial lakes in the south of Iceland under the Vatnajökull . The western burglar boiler is on N 64 ° 29'25 ", W 17 ° 30'15", the eastern one on N 64 ° 29'75 ", W 17 ° 37'0".

Surname

The lakes are called Kessel der Skaftá in English , whereby katlar is the plural of ketill (dt. Kessel ) and Skaftá is the name of their outflow.

Location and area of ​​influence

About 10 km northwest of Grímsvötn there are two burglary kettles in the ice field of Vatnajökull, the so-called Skaftárkatlar. The larger one is the eastern basin. The diameter of the largest is almost 3 km, the western one has a diameter of approx. 2 km. Below that lies a fairly large high temperature area with an estimated capacity of at least 500 MW for the smaller western boiler alone.

The Skaftárkatlar empty themselves regularly through one or more glacier runs , v. a. in the river Skaftá . The Skaftárkatlar are actually located near the Tungnaárjökull and Sylgjujökull glacier tongues . Nevertheless, their waters run off over the Skaftájökull . This can now be explained by geological conditions: The waters follow a valley and crevices in the terrain below the glacier, initially east of a ridge that is oriented from southwest to northeast and which is an extension of Fögrufjöll. Later the water crosses the ridge and flows on its west side into a western arm of the Skaftá.

However, researchers also support the assumption that a considerable part of the thawed water does not flow into the glacial lakes at all, but rather seeps underground into the rock to reappear as sulphate-rich springs in the lowlands.

In addition, it has been proven in individual cases that water from the Skaftárkatlar came to light during a glacier run in the rivers Hverfisfljót and Djúpá. This can be explained by the influence of surges in the affected glacier tongues. Even a particularly large glacier run can cause part of the overflow fluid to be diverted, as observed in 2006 in the Tungnaá River during a glacier run from the eastern basin.

Regular glacier runs

Similar to the Grímsvötn, only more regularly, a lake, more precisely a kind of water bubble, arises every 1 to 3 years under each burglary in an ice cave under the glacier cover. The lower ice cover in the basin rises by 70–100 m. Lately this has been shortened to a one-year interval.

These lakes are usually formed by the continuous thawing of the glacial ice over the high temperature area below . The western burglar boiler produces around 6,000,000 l per month, the eastern, larger one 9,000,000 l per month. When the lake has reached a certain height, the glacier ice floats on it and a glacier flow flows out from under the Skaftárjökull glacier , which in recent years and centuries has never reached catastrophic proportions in the Skaftá river and usually between 1,000 and 2000 m³ / s includes.

On the other hand, the glaciers in the Skaftá always grow very quickly.

When the Skaftá glacier runs, the water initially flows over 40 km under the glacier until it finally emerges in the Skaftá river. When the water flows out of the lakes, the boilers collapse (further). A depth of 150 m was measured in the east and 100 m in the west. Shortly before a glacier run, the ground has risen to such an extent that they are only 20, 30, 40 m deep.

However, the glacier courses of the two Skaftárkatlar differ from each other, whereby the one from the eastern basin is larger. Both usually last around 2 days.

History of the Skaftá glacier runs

Until 2015

Since 1955 45 glacier runs have been measured in the Skaftá.

Until 1954 there were repeatedly smaller glacier runs, often associated with volcanic activity under the glacier. After 1954 this seems to have increased somewhat.

In 2010 there were two glacier runs from the Skaftárkatlar with a maximum amount of approx. 1,400 m³ / s on June 28, 2010, at the end of July 2011 a smaller glacier run began again, from the western, smaller basin. The glacier run from the western basin was on 5 August has largely subsided. The highest amount of water measured at Sveinstindur was 403 m³ / s. The eastern basin had also changed and enlarged so that a glacier run could come out of it.

2015

At the end of September and beginning of October 2015 another glacier run was detected , this time from the Eystri Skaftárketill . The ice kettle has sunk by approx. 72 m so far. The highest amount of water measured at a station so far was approx. 2100 m² / sec. at Sveinstindur. However, scientists suspect that the total amount would be much larger (up to 3,000 m² / sec), as only a smaller part would be recorded at the station. The water contains a lot of sediments.

In the meantime, the volcanological institute of the University of Iceland has published preliminary measurement results with corresponding drawings (see web links or receipt). Accordingly, the deepest sinking of the cauldron in the ice was 120 m, in an area of ​​10–12 km² the cauldron sank by more than 3 m, on 6.5 km² more than 10 m. The boiler itself has a volume of 300 ± 20 million m³, the total amount of the leaked water 366 ± 44 million m³ including the condensation water that was added on the way. It is clear from the drawings that the kettle has become wider at the bottom and has thus increased overall.

Gases

These glacier runs of the Skaftá usually bring with them volcanic gases such as sulfur dioxide . In higher concentration, i.e. H. near the glacier, these can exceed harmful limits. During the 2015 glacier run, there was also a warning against approaching the Skaftárjökull, Sylgjujökull and Tungnaárjökull glaciers, as well as the upper reaches of the Skaftá, because dangerous gas concentrations can be found there. East Iceland is also affected by the current wind direction.

See also

Photos, videos and maps

Scientific contributions

Web links

Individual evidence

  1. ↑ a b Bergur Einarsson: Jökulhlaups in Skaftá. A study of jökulhlaup from the Western Skaftá cauldron in the Vatnajökull icecap, Iceland. Veðurstofa Íslands, Skyrsla, VÍ 2009-006, 25 (PDF file; 5.9 MB) (Icelandic / English); Accessed August 5, 2011
  2. ^ HU Schmid: Dictionary Icelandic - German. Buske, Hamburg, 127
  3. ↑ a b Magnús Tumi Guðmundsson, Þórdís Högnadóttir: Skaftárkatlar , Jarðvísindastofnun Íslands (Icelandic); Accessed August 5, 2011
  4. ↑ a b c d Bergur Einarsson: Jökulhlaups in Skaftá. A study of jökulhlaup from the Western Skaftá cauldron in the Vatnajökull icecap, Iceland. Veðurstofa Íslands, Skyrsla, VÍ 2009-006, 5 (PDF file; 5.9 MB) (Icelandic / English); Accessed August 5, 2011
  5. ↑ a b c Bergur Einarsson: Jökulhlaups in Skaftá. A study of jökulhlaup from the Western Skaftá cauldron in the Vatnajökull icecap, Iceland. Veðurstofa Íslands, Skyrsla, VÍ 2009-006, 35 (PDF file; 5.9 MB) (Icelandic / English); Accessed August 5, 2011
  6. ^ Bergur Einarsson: Jökulhlaups in Skaftá. A study of jökulhlaup from the Western Skaftá cauldron in the Vatnajökull icecap, Iceland. Veðurstofa Íslands, Skyrsla, VÍ 2009-006, 28 (PDF file; 5.9 MB) (Icelandic / English); Accessed August 5, 2011.
  7. ^ Bergur Einarsson: Jökulhlaups in Skaftá. A study of jökulhlaup from the Western Skaftá cauldron in the Vatnajökull icecap, Iceland. Veðurstofa Íslands, Skyrsla, VÍ 2009-006, 37 (PDF file; 5.9 MB) (Icelandic / English); Accessed August 5, 2011.
  8. ↑ cf. History of the glacier runs
  9. ↑ Vegahandbókin. Ed. Landmælingar Íslands. 2006, p. 127
  10. ↑ a b Bergur Einarsson: Jökulhlaups in Skaftá. A study of jökulhlaup from the Western Skaftá cauldron in the Vatnajökull icecap, Iceland. Veðurstofa Íslands, Skyrsla, VÍ 2009-006, 29 (PDF file; 5.9 MB) (Icelandic / English); Accessed August 5, 2011
  11. ↑ Skaftárhlaup í júní 2010 , Fréttir, Veðurstofa Íslands, November 30, 2011 (Icelandic); Accessed November 30, 2011
  12. ↑ Afleiðingar Skaftárhlaups , Fréttir, RÚV, July 13, 2010 (Icelandic); Accessed July 30, 2011
  13. ↑ Hlaupið í Skaftá, Fréttir, Veðurstofa Íslands, November 29, 2011 (Icelandic); Accessed November 30, 2011
  14. ↑ cf. also Aukið vatnsmagn í Skaftá , Vísir, November 30, 2011 (Icelandic); Accessed November 30, 2011
  15. ↑ Telur líkur á öðru hlaupi , Morgunblaðið, August 6, 2011 (Icelandic); Accessed August 6, 2011
  16. ↑ Possibly the largest jökulhlaup. Iceland Met Office, October 1, 2015; Accessed October 1, 2015.
  17. ↑ Ice subsidence above eastern Skaftá cauldron. Jökulhlaup - the largest to have occurred . Iceland Met Office; Accessed October 1, 2015.
  18. ^ [1] Iceland Met Office; Accessed October 1, 2015.
  19. ↑ Þetta er alveg gríðarleger flóð , RÚV , October 2, 2015, accessed: November 13, 2015.
  20. ↑ RÚV við upptökin - mikið sjónarspil , RÚV, October 1, 2015, accessed: November 13, 2015.
  21. ↑ Preliminary scientific results for Skaftáhlaup 2015 , Vulkanolog. Inst., Univ. v. Iceland; downloaded on November 13, 2015
  22. ↑ Skaftárhlaup: Varað við Brennisteinsmengun , Vísir , June 20, 2010 (Icelandic); Accessed July 30, 2011
  23. ↑ Skaftá at Nat.is (English)
  24. ↑ Quotation: “Note: Along with the flood water the release of volcanic gases is expected. The gases (ie H2S and SO2) move downwind from Skaftá towards the eastern part of Iceland. " (English) IMO, Main page; Accessed October 1, 2015.
  25. ↑ [2] Hveralykt berst yfir Austurland , RÚV, October 1, 2015; Accessed October 1, 2015.