Katla_(volcano)

Katla (volcano)

Katla (volcano)

Large volcano on Southern Iceland

For other uses, see Katla (disambiguation).

Katla (Icelandic pronunciation: [ˈkʰahtla] ⓘ) is an active volcano in southern Iceland. This volcano has been very active historically with at least twenty documented major eruptions since 2920 BC. In its recent history though, Katla has been less active as the last major eruption occurred in 1918. These eruptions have had a Volcanic Explosivity Index (VEI) of between 4 and 5 on a scale of 0 to 8. In comparison, the Eyjafjallajökull 2010 eruption had a VEI of 4. Larger VEI-5 eruptions are comparable to Mount St. Helens 1980 eruption. Several smaller (minor) eruptions measuring VEI-1 and below have occurred since, with the most recent being in 1999.[4]

Quick Facts Highest point, Elevation ...

Katla is one of the largest volcanic sources of carbon dioxide (CO2) on Earth, accounting for up to 4% of total global volcanic carbon dioxide emissions.[5]

Geography and physical appearances

Katla is one of the largest volcanoes in Iceland.[6] It is situated to the north of Vík í Mýrdal and to the east of the smaller glacier Eyjafjallajökull. Its peak reaches 1,512 metres (4,961 ft) and is partially covered by the Mýrdalsjökull glacier. The system has an area of 595 km2 (230 sq mi). The Eldgjá canyon is part of the same volcanic system,[7][8] and extends as a fissure swarm to the north-east. The lavas from this eruption in 939 to 940 almost reach the south eastern coast, although are partially buried.[9]

The caldera of the Katla volcano has a diameter of 10 km (6 mi) and is covered with 200–700 metres (660–2,300 ft) of ice. The volcano normally erupts every 40–80 years.[6] The flood discharge at the peak of an eruption in 1755 has been estimated at 200,000–400,000 m3/s (7.1–14.1 million cu ft/sec), comparable to the combined average discharge of the Amazon, Mississippi, Nile, and Yangtze rivers (about 266,000 m3/s (9.4 million cu ft/sec)).

Etymology

The name Katla derives from the word ketill ("kettle"), referring to the form of the volcano. Katla is also used as a female first name.[10]

Historic activity

Locations of caldera rim and previous eruptions from 1755 to 1999.

At least twenty-eight eruptions with a known VEI have been recorded for Katla since 2920 BC. The last major eruption started on 12 October 1918 and lasted for 24 days.[2] It was likely a VEI-5 level eruption. The 1918 eruption resulted in extending the southern coast by 5 km due to laharic flood deposits. Its present dormancy is among the longest in known history.[11]

Most of these eruptions resulted in glacial floods. Before the Hringvegur (Iceland's Ring Road) was constructed in 1974, people feared traversing the plains in front of the volcano because of the frequent jökulhlaup (or glacier bursts) and the deep river crossings. Especially dangerous was the glacier outburst that followed the eruption of 1918.

Recent activity

Schematic cross-section from west to east across the Eyjafjallajökull and Katla volcanoes. Magmatic intrusions are drawn in red, rhyolitic domes and the cryptodome in yellow; glaciers are shown in light blue.

Katla has been showing signs of unrest since 1999, and geologists have concerns that it might erupt in the near future.[12] Particularly, monitoring has been intensified following the March 2010 eruptions of a smaller neighbouring volcano, the Eyjafjallajökull glacier.[13] The eruption of this nearby long-dormant volcano in March and April 2010 prompted fears among some geophysicists that it might trigger an eruption at the larger and more dangerous Katla.[14][15][16] In the past 1,000 years, all three known eruptions of Eyjafjallajökull have triggered subsequent Katla eruptions.[15]

Following the 2010 Eyjafjallajökull eruptions, on 20 April 2010 Icelandic President Ólafur Grímsson said "the time for Katla to erupt is coming close ... we [Iceland] have prepared ... it is high time for European governments and airline authorities all over Europe and the world to start planning for the eventual Katla eruption".[17]

Increased earthquake activity has been noticed on Katla since the eruption at Eyjafjallajökull, but no other signs of an imminent eruption have been observed. These quakes are located mainly on the northwestern rim of the caldera. On 9 October 2010, a sudden rise in harmonic tremor was observed in the stations around Katla, a sign of a possible impending eruption.[18]

As of 2010, volcanologists are continuing to monitor Katla, aware that any eruption from Katla following an eruption from Eyjafjallajökull has historically occurred within months of the latter. The Icelandic Meteorological Office updates its website with reports of quakes both at Eyjafjallajökull and Katla.[19]

2011 activity

In 2011, geologic activity led many to speculate that a very small subglacial eruption had taken place.[4] In June 2011, harmonic tremor was again detected at Katla volcano. A few days later, an earthquake swarm took place in the caldera, indicating magma movement inside the volcano, leading to increased fears of an eruption in the near future.[20]

On 8 and 9 July, another spike in harmonic tremors occurred, as a small eruption of Katla took place. Cracks formed on the glacier, as well as a cauldron.[21] Icelandic media reported a small subglacial eruption might have started.[22] On the morning of 9 July, a glacier flood was reported in the river Múlakvísl, and also later in the river Skálm. The bridge across Múlakvísl was destroyed as well as other parts of the road, Route 1, on the Icelandic ring road. Helicopter pilots flying over the glacier also reported cracks in the glacier.[23] Scientists monitoring the activity said speculation that it was caused by a "very small" subglacial eruption lacked confirmation by visual or seismic evidence.[4]

2016 and 2017 activity

Tremors were detected under Katla in late August 2016.[24][25]

A "Specialist Description" describing the activity on 29 August 2016 noted that there was:

... a seismic swarm in Mýrdalsjökull on the 29th of August with two events in the northern Katla caldera rim measured at magnitude 4.5. These are the biggest earthquakes in Katla volcano since 1977. Earthquake eruption checks confirmed that most earthquakes occurred between 0:40 and 1:50 PM. The big earthquakes were about thirty seconds apart at 1:47. They were followed by more than 50 aftershocks until 15:12 PM, when there was an earthquake of magnitude 3.3 and then the cycle and seismic activity in the region reduced again. No unrest was measured along these earthquakes. The geothermal has decreased in the following week and is now negligible.[26]

An update written at 11 Sep 16:38 GMT reported:

Today, shortly before 14:00, a small earthquake swarm began in Mýrdalsjökull. The largest earthquakes of the swarm were of magnitude 3.3 and 3.0 at 16:12 and 15:57. More than 10 smaller earthquakes were detected in the swarm. All of the earthquakes were shallow and located in the caldera of Katla volcano. It is not unusual for seismic swarms of this type to occur in this area.[27]

In February 2017, seismic activity at the volcano continued.[28]

More information Start Date, End Date ...

Folklore

"Katla eða Kötlugjá" redirects here

In folklore, the witch named Katla is held responsible for causing the jökulhlaup (outburst) of the Mýrdalsjökull glacier over the volcano; these events are dubbed Kötluhlaup (or "Katla's eruption"[29]).[30] The folktale recorded by Jón Árnason in 1862[31] probably dates much older since it is set in the time of the Þykkvabæjarklaustur [is], the Catholic monastery abolished c. 1550.[32]

The short folktale entitled "Katla eða Kötlugjá" can be summarized as follows: In the pre-Reformation days when the Þykkvibær monastery was installed with an abbot, they had a cranky housekeeper there named Katla, well versed in (ancient) magic (fjölkynngi), instilling fear in others.[32] She owned a magical pair of breeches (brók, 'trousers'), which allowed its wearer to run endlessly without fatigue, but herself reserved its use for an emergency. One day in autumn, the abbot's shepherd Barði has trouble rounding up the sheep before master and the housekeep return from a banquet, and he borrows the breeches to retrieve the stray. Katla discovers the transgression and ambushes him, drowning him in a vat of sour whey (sýruker).[33] But as winter wore on, the whey began to dwindle and Katla was heard muttering "Barði will soon appear".[34] Realizing the discovery of her crime and punishment was imminent, she put on her breeches and disappeared to the northwest, presumably diving straight into the glacier. Right afterwards a glacial outburst (jökulhlaup) occurred that rushed towards the monastery and Álftaver [is].[31][35]

Other geologic features such as Kötlugja ('Katla's gorge') and the surrounding area made desolate, named Kötlusandur also bear names alluding to the Katla folklore.[35]

Images

  • The Mýrdalsjökull glacier in 2005
  • The Mýrdalsjökull glacier in 2005

Katla is the subject of Katla, an Icelandic TV series produced for Netflix.

See also

Notes

  1. The 1918 eruption lasted until November 4 of that year)
  2. The 1918 eruption lasted until August 15 of that year)
  3. In millions
  4. ±45 days
  5. ±3 years
  6. ±12 years
  7. ±50 years
  8. ±12 years
  9. ±40 years

References

Citations
  1. [1]
    "Katla Volcano". Institute of Earth Sciences. University of Iceland. Archived from the original on 9 November 2009. Retrieved 12 March 2010.
  2. [2]
    "Katla Volcano News". Retrieved 18 October 2014.
  3. [3]
    "Global Volcanism Program – Katla". Archived from the original on 22 April 2010. Retrieved 18 October 2014.
  4. [4]
    "Katla volcano in Iceland remains dormant". IceNews. 9 July 2011. Archived from the original on 15 August 2012. Retrieved 9 July 2011.
  5. [5]
    Ilyinskaya, Evgenia; Mobbs, Stephen; Burton, Ralph; Burton, Mike; Pardini, Federica; Pfeffer, Melissa Anne; Purvis, Ruth; Lee, James; Bauguitte, Stéphane (2018). "Globally significant CO2 emissions from Katla, a subglacial volcano in Iceland" (PDF). Geophysical Research Letters. 45 (19): 10, 332–10, 341. Bibcode:2018GeoRL..4510332I. doi:10.1029/2018gl079096. ISSN 0094-8276. S2CID 52832814.
  6. [6]
    Budd, David A.; Troll, Valentin R.; Dahren, Börje; Burchardt, Steffi (2016). "Persistent multitiered magma plumbing beneath Katla volcano, Iceland". Geochemistry, Geophysics, Geosystems. 17 (3): 966–980. Bibcode:2016GGG....17..966B. doi:10.1002/2015GC006118. ISSN 1525-2027.
  7. [7]
    "Katla". Global Volcanism Program. Smithsonian Institution. Retrieved 26 March 2010.
  8. [8]
    Gudmundsson, Magnús T.; Thórdís Högnadóttir (January 2007). "Volcanic systems and calderas in the Vatnajökull region, central Iceland: Constraints on crustal structure from gravity data". Journal of Geodynamics. 43 (1): 153–169. Bibcode:2007JGeo...43..153G. doi:10.1016/j.jog.2006.09.015.
  9. [9]
    Moreland, William Michael; Thordarson, Thor; Houghton, Bruce F.; Larsen, Gudrún (28 August 2019). "Driving mechanisms of subaerial and subglacial explosive episodes during the 10th century Eldgjá fissure eruption, southern Iceland". Volcanica. 2 (2): 129–150. doi:10.30909/vol.02.02.129150. ISSN 2610-3540. S2CID 202923626.
  10. [10]
    "Katla – Nordic Names Wiki – Name Origin, Meaning and Statistics". Retrieved 18 October 2014.
  11. [11]
    "The Katla eruption in 1918". Institute of Earth Sciences. University of Iceland. Archived from the original on 2 November 2005. Retrieved 4 May 2010.
  12. [12]
    Soosalu, Heidi. "Katla seismicity". Institute of Earth Sciences. University of Iceland. Archived from the original on 4 November 2007. Retrieved 12 March 2010.
  13. [13]
    "Hard to Predict How Long Iceland Eruption Will Last". Iceland Review. Iceland. 21 March 2010. Archived from the original on 5 June 2011. Retrieved 21 March 2010.
  14. [14]
    Volcano erupts in south Iceland BBC online news. Retrieved 21 March 2010.
  15. [15]
    Boyes, Roger (21 March 2010). "Iceland prepares for second, more devastating volcanic eruption". The Times. London. Retrieved 22 March 2010.
  16. [16]
    "Icelandic Volcano May Cause Bigger Eruption". Reuters. 22 March 2010. Retrieved 20 April 2010.
  17. [17]
    "BBC Newsnight interview with President Grímsson of Iceland, 20 April 2010". Retrieved 18 October 2014.
  18. [18]
    Frímann, Jón. "Sudden rise in harmonic tremors around Katla and Eyjafjallajökull". Iceland Volcano and Earthquake Blog. Archived from the original on 12 October 2010. Retrieved 30 December 2010.
  19. [19]
    "Iceland Meteorological office – Earthquakes Mýrdalsjökull, Iceland". Icelandic Meteorological office. Retrieved 18 October 2014.
  20. [20]
    Frímann, Jón (17 June 2011). "Earthquake swarm in Katla volcano". Iceland Volcano and Earthquake Blog. Archived from the original on 4 May 2012. Retrieved 18 October 2011.
  21. [21]
    "Katla". Global Volcanism Program. Retrieved 18 October 2014.
  22. [22]
    "Hlaup hafið í Múlakvísl". Morgunblaðið (in Icelandic). 9 July 2011. Retrieved 18 October 2011.
  23. [23]
    "Sjá sprungur í jöklinum". Morgunblaðið (in Icelandic). 9 July 2011. Retrieved 18 October 2011.
  24. [24]
    "Earthquake Activity Page". vedur.is. Icelandic Meteorological Office. Retrieved 29 August 2016.
  25. [25]
    "Largest quakes to hit Katla volcano in decades". icelandreview.com/. Archived from the original on 14 October 2017. Retrieved 29 August 2016.
  26. [26]
    "11.9.2016". vedur.is. Icelandic Meteorological Office. 11 September 2016.
  27. [27]
    "[no title cited]". vedur.is. Icelandic Meteorological Office.
  28. [28]
    "Continuing seismic activity in the Katla volcano". Iceland Monitor. 2 February 2017.
  29. [29]
    Thor Thordarson [in Icelandic]; Ármann Höskuldsson [in Icelandic] (2014). Iceland: Classic Geology in Europe. Dunedin Academic Press Ltd. ISBN 9781780465111.
  30. [30]
    Nordvig (2019), p. 67.
  31. [31]
    "Katla eða Kötlugjá" . Íslenzkar Þjóðsögur og Æfintýri  (in Icelandic). Vol. 1. 1862. pp. 184–185 – via Wikisource.
  32. [32]
    Nordvig (2019), p. 74–75.
  33. [33]
    Corrected to nominative case from Nordvig (2019), p. 76.
  34. [34]
    After Helgi Björnsson (2016), p. 225 "Barði will soon appear". Cf. Zoëga (1922) Icelandic-English dictionary s.v. "brydda" : impers. bryddir á e-u something begins to appear
  35. [35]
    Helgi Björnsson (2016), pp. 224–225.
Bibliography

Media related to Katla at Wikimedia Commons
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