Katla (volcano)

Katla (Icelandic pronunciation: [ˈkʰahtla] ⓘ) is an active volcano in southern Iceland. This particular 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]

For other uses, see Katla.

Katla
Katla eruption, 1918
Highest point
Elevation1,512 m (4,961 ft)[1]
ListingList of volcanoes in Iceland
Coordinates63°38′N 19°03′W
Geography
Katla is located in Iceland
Katla
Katla
Iceland
Geology
Mountain typeSubglacial volcano
Last eruptionOctober 12, 1918[lower-alpha 1] (Major)[2]
July 17, 1999[lower-alpha 2] (Minor)[3]

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]

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.[9]

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.[10]

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.

Start Date[3] End Date[3] VEI[3] Scale Tephra volume[lower-alpha 3]
(km³)[3]		 Summary
July 17, 1999 August 15, 1999 0 Minor Un­known This eruption is uncertain, and could have been subglacial
June 25, 1955 Un­known 0 Minor Un­known This eruption is uncertain, and could have been subglacial
October 12, 1918 November 4, 1918 4+ Major 700 Last major eruption of Katla.
May 8, 1860 May 27, 1860 4 Major 200 Dated using historical records.
June 26, 1823 July 23, 1823 3 Minor 100 This eruption was dated using historical records. The eruption "VEI" is speculated.
October 17, 1755 February 13, 1756 5 Major 1500 This eruption was dated using historical records. The eruption "VEI" is speculated.
May 11, 1721 October 15, 1721[lower-alpha 4] 5 Major 1200 This eruption was dated using historical records. The eruption "VEI" is speculated.
November 3, 1660 1661 4 Major 200 Dated using historical records.
September 2, 1625 September 14, 1625 5 Major 1500 Dated using historical records.
October 12, 1612 Un­known 4 Major 200 Dated using historical records.
August 11, 1580 Un­known 4 Major 200 Dated using historical records.
1550 Un­known 4 Major 200 The estimated date is based on Tephrochronology.
1500 Un­known 4 Major 200 The estimated date is based on Tephrochronology.
1440 Un­known 4 Major 200 Dated using historical records.
1416 Un­known 4 Major 200 While this eruption is dated using historical records, the VEI and tephra volume amounts are speculated.
1357[lower-alpha 5] Un­known 4 Major 700 Dated using historical records.
1262 Un­known 5 Major 1500 Dated using historical records.
1245 Un­known 4 Major 200 Dated using historical records.
1210 Un­known 4 Major 100 The estimated date is based on Tephrochronology.
1177 Un­known 3 Minor 10 Dated using historical records.
960 Un­known 3 Minor 50 The estimated date is based on Tephrochronology.
934 Un­known 4 Major 5000 The estimated date and VEI are based on an ice core.
920 Un­known 4 Major 200 Dated using historical records.
270[lower-alpha 6] Un­known 3 Minor 85 Based on Radiocarbon dating.
-850 850 BC[lower-alpha 7] Un­known 4 Major 290 Based on Radiocarbon dating.
-1220 1220 BC[lower-alpha 8] Un­known 3 Minor 65 Based on Radiocarbon dating.
-1440 1440 BC[lower-alpha 9] Un­known 4 Major 220 Based on Radiocarbon dating.
-1920 1920 BC Un­known 4 Major 130 Based on Radiocarbon dating.
-2920 2920 BC Un­known 3 Minor 75 The estimated date is based on Tephrochronology.

Present day 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.[11] Particularly, monitoring has been intensified following the March 2010 eruptions of a smaller neighbouring volcano, the Eyjafjallajökull glacier.[12] 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.[13][14][15] In the past 1,000 years, all three known eruptions of Eyjafjallajökull have triggered subsequent Katla eruptions.[14]

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".[16]

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.[17]

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.[18]

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.[19]

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.[20] Icelandic media reported a small subglacial eruption might have started.[21] 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.[22] 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.[23][24]


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.[25]

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.[26]

In February 2017, seismic activity at the volcano continued.[27]

Images
  • The Mýrdalsjökull glacier in 2005
    The Mýrdalsjökull glacier in 2005
  • 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
  1. "Katla Volcano". Institute of Earth Sciences. University of Iceland. Archived from the original on 9 November 2009. Retrieved 12 March 2010.
  2. "Katla Volcano News". Retrieved 18 October 2014.
  3. "Global Volcanism Program – Katla". Archived from the original on 22 April 2010. Retrieved 18 October 2014.
  4. "Katla volcano in Iceland remains dormant". IceNews. 9 July 2011. Archived from the original on 15 August 2012. Retrieved 9 July 2011.
  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. 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. "Katla". Global Volcanism Program. Smithsonian Institution. Retrieved 26 March 2010.
  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. "Katla – Nordic Names Wiki – Name Origin, Meaning and Statistics". Retrieved 18 October 2014.
  10. "Archived copy". Archived from the original on 2 November 2005. Retrieved 4 May 2010.{{cite web}}: CS1 maint: archived copy as title (link)
  11. Soosalu, Heidi. "Katla seismicity". Institute of Earth Sciences. University of Iceland. Archived from the original on 4 November 2007. Retrieved 12 March 2010.
  12. "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.
  13. Volcano erupts in south Iceland BBC online news. Retrieved 21 March 2010.
  14. Boyes, Roger (21 March 2010). "Iceland prepares for second, more devastating volcanic eruption". The Times. London. Retrieved 22 March 2010.
  15. "Icelandic Volcano May Cause Bigger Eruption". Reuters. 22 March 2010. Retrieved 20 April 2010.
  16. "BBC Newsnight interview with President Grímsson of Iceland, 20 April 2010". Retrieved 18 October 2014.
  17. 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.
  18. "Iceland Meteorological office – Earthquakes Mýrdalsjökull, Iceland". Icelandic Meteorological office. Retrieved 18 October 2014.
  19. 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.
  20. "Katla". Global Volcanism Program. Retrieved 18 October 2014.
  21. "Hlaup hafið í Múlakvísl". Morgunblaðið (in Icelandic). 9 July 2011. Retrieved 18 October 2011.
  22. "Sjá sprungur í jöklinum". Morgunblaðið (in Icelandic). 9 July 2011. Retrieved 18 October 2011.
  23. "Earthquake Activity Page". vedur.is. Icelandic Meteorological Office. Retrieved 29 August 2016.
  24. "Largest quakes to hit Katla volcano in decades". icelandreview.com/. Archived from the original on 14 October 2017. Retrieved 29 August 2016.
  25. "11.9.2016". vedur.is. Icelandic Meteorological Office. 11 September 2016.
  26. "[no title cited]". vedur.is. Icelandic Meteorological Office.
  27. "Continuing seismic activity in the Katla volcano". Iceland Monitor. 2 February 2017.
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