Grímsvötn

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Template:Short description Template:Infobox mountain Grímsvötn (Script error: No such module "IPA".;[1] vötn = "waters", singular: Script error: No such module "Lang".) is an active volcano with a (partially subglacial) fissure system located in Vatnajökull National Park, Iceland. The central volcano is completely subglacial and located under the northwestern side of the Vatnajökull ice cap. The subglacial caldera is at Script error: No such module "Coordinates"., at an elevation of Script error: No such module "convert".. Beneath the caldera is the magma chamber of the Grímsvötn volcano.

Grímsvötn is a basaltic volcano which has the highest eruption frequency of all the volcanoes in Iceland. It has a southwest-northeast-trending fissure system. The massive climate-impacting Laki fissure eruption of 1783–1784 took place in a part of the same Grímsvötn-Laki volcanic system.[2] Grímsvötn was erupting at the same time as Laki during 1783, but continued to erupt until 1785. Because most of the volcanic system lies underneath Vatnajökull, most of its eruptions have been subglacial and the interaction of magma and meltwater from the ice causes phreatomagmatic explosive activity.[3] Within the Grímsvötn-Laki volcanic system is a second central volcano called Thordarhyrna (Þórðarhyrna).[4]

Jökulhlaup

Eruptions in the caldera regularly cause glacial outbursts known as jökulhlaup.[5] Eruptions or geothermal activity, melt enough ice to fill the Grímsvötn caldera with water, and the pressure may be enough to suddenly lift the ice cap, allowing huge quantities of water to escape rapidly. Earthquakes and seismic tremor may occur.[6] Jökulhlaup can occur independent of eruptions or be followed by eruptions.[6] Jökulhlaup independent of eruptions occurred in November, December 2021 and October 2022.[6] Jökulhlaup which were followed by eruptions occurred in 1922, 1934 and 2004.[6] Consequently, the Grímsvötn caldera is monitored very carefully.

When a large eruption occurred in 1996, geologists knew well in advance that a glacial burst was imminent. It did not occur until several weeks after the eruption finished, but monitoring[7] ensured that the Icelandic ring road (Hringvegur) was closed when the burst occurred. A section of road across the Skeiðará sandur was washed away in the ensuing flood, but no one was hurt.

Eruption history between 1990 and today

Gjálp 1996

(See also the main article: 1996 eruption of Gjálp

The Gjálp fissure vent eruption in 1996 revealed that an interaction may exist between Bárðarbunga and Grímsvötn. A strong earthquake at Bárðarbunga, about magnitude 5, is believed to have been related to the triggering of the eruption in Gjálp.[8] On the other hand, because the magma erupted showed strong connections to the Grímsvötn Volcanic System according to petrology studies, the 1996 as well as a former eruption at Gjálp in the 1930s are thought to have taken place within Grímsvötn Volcanic system.[9][10]

1998 and 2004 eruptions

File:NASA Photo Grímsvötn Nov. 2004.jpg
Satellite images of the November 2004 Grímsvötn Eruption. The lower image assigns a false color (red) to the surface ice.

A week-long eruption occurred at Grímsvötn starting on 28 December 1998, but no glacial burst occurred. In November 2004, a week-long eruption occurred. Volcanic ash from the eruption fell as far away as mainland Europe and caused short-term disruption of airline traffic into Iceland, but again no glacial burst followed the eruption.

2011 eruption

Script error: No such module "Labelled list hatnote". Harmonic tremors were recorded twice around Grímsvötn on 2 and 3 October 2010, possibly indicating an impending eruption.[11] At the same time, sudden inflation was measured by GPS in the volcano, indicating magma movement under the caldera. On 1 November 2010 meltwater from the Vatnajökull glacier was flowing into a lake, suggesting that an eruption of the underlying volcano could be imminent.

File:Grímsvötn Volcano Showing Plume - May 22.jpg
Satellite image from 22 May 2011 of the volcanic plume above Iceland
File:Grimsvötn ash cloud.jpg
View of Icelandic landscape beneath the ash-cloud during the 2011 eruption
File:Grimsvötn August 2011.jpg
Grímsvötn in August 2011. Ash covering the surrounding snow and ice

On 21 May 2011 at 19:25 UTC, an eruption began, with Script error: No such module "convert". high plumes accompanied by multiple earthquakes,[12][13][14][15] Until 25 May, the eruption scale had been larger than that of the 2010 eruption of Eyjafjallajökull.

The ash cloud from the eruption rose to Script error: No such module "convert"., and was so far 10 times larger than the 2004 eruption, and the strongest in Grímsvötn in the last 100 years.[16]

File:Iceland’s Grimsvotn Volcano.jpg
Satellite image from 23 May 2011 of the ash-cloud to the south of Iceland

Disruption to air travel in Iceland[17] commenced on 22 May, followed by Greenland, Scotland,[18] Norway, Svalbard[19] and a small part of Denmark on subsequent days. On 24 May the disruption spread to Northern Ireland and to airports in northern England.[17] The cancellation of 900 out of 90,000 European flights[20] in the period 23–25 May was much less widespread than the 2010 disruption after the Eyjafjallajökull eruption.

The eruption stopped at 02:40 UTC on 25 May 2011, although there was some explosive activity from the eruptive vents affecting only the area around the crater.[21][22][23]

2020 onward threats of eruption

In June 2020, the Icelandic Meteorological Office (IMO) issued a warning that an eruption might take place in the coming weeks or months, following scientists reporting high levels of sulfur dioxide, which is indicative of the presence of shallow magma. IMO warned that a glacial flood as a result of melting ice could trigger an eruption.[24] No eruption occurred.

In September 2021, an increase in water outflow from under the Vatnajökull ice cap was reported. The water contains elevated levels of dissolved hydrogen sulfide, suggesting increased volcanic activity under the ice.[25] Jökulhlaup (glacial lake flooding) can occur before or after an eruption.

On 4 December 2021, a jökulhlaup occurred from Grímsvötn into the Gígjukvísl river, with an average flow of Script error: No such module "convert".. Two days later, the Icelandic Meteorological Office increased the alert level for Grímsvötn from yellow to orange, after a series of earthquakes was detected. On 7 December, the alert level was lowered back to yellow, after seismic activity decreased and no signs of eruptive activity were detected.[26]

On 11 December 2023, a jökulhlaup followed in time,[6] a Template:M earthquake.[27]

Eruption history before 1990

Tephra studies on soil samples from around the Vatnajökull ice-cap, show that the Grímsvötn volcanic system has high activity for Iceland, and had between 4 to 14 explosive eruptions every 100 years (mean about 7 eruptions every 100 years) between 7600 years ago and 870 AD.[28] For technical reasons only the last 10,200 years of explosive eruptions have been characterised locally,[29] and the record gets more inaccurate with time especially prior to 1598, which is first eruption timed to the day.[30] The Laki eruptions which were both effusive and explosive between June 1783 and February 1784,[31] produced the Skaftáreldahraun lava flows, which cover a large part of south-east Iceland.[2] Before this the tip of the Rauðhólar-Eldgígur fissure system was active with the production of the 4550 BCE Botnahraun lava flow which extends beyond the furtherest extent to the south of the Laki lava field.[2] The Rauðhólar-Eldgígur fissure system also formed the Núpahraun lava flows around 4000 BP[31] that extend from the Vatnajökull glacier towards the south east coast and are covered in part by the northern Laki Skaftáreldahraun lava flow.[2] There are two recent pre-historic but undated Bergvatnsárhraun lava flows just on the south-eastern edge of the Vatnajökull glacier, related to the line of the Rauðhólar-Eldgígur fissures.[2]

Eruptions Grímsvötn volcanic system last 10,000 years (unconfirmed eruptions not shown)
Standard Date Date Cal BP Lake Lögurinn tephra thickness VEI Comment
2011 - - 4 [30]
2004 - - 3 [30]
1998 - - 3 [30]
1996 - - 3 [30]
1983 - - 2 [30]
1954 - - 1 [30]
1938 12 - 4 [30]
1934 16 - 2 [30]
1933 17 - 1 [30]
1922 28 Template:Cvt 2 [30],Lake Lögurinn core.[29]
1919 31 - 2 [30]
1910 40 - - [30]
1897 53 - 2 [30]
1891 -41 - 2 [30]
1883 67 - 2 [30]
1873 77 - 4 [30]
1867 83 - 1 [30]
1854 96 - 2 [30]
1838 112 - 2 [30]
1816 134 - 2 [30]
1783 167 - 4 [30] Laki eruption.
1774 176 - 2 [30]
1768 182 - 2 [30]
1753 197 - 2 [30]
1730 220 - 2 [30]
1725 225 - 2 [30]
1716 234 - 2 [30]
1706 244 - 2 [30]
1697 253 - - [30]
1684 266 - 2 [30]
1681 269 - - [30]
1665 285 Template:Cvt - [30]Approx 280 BP eruption Lake Lögurinn core.[29]
1659 291 - 2 [30]
1638 312 - 2 [30]
1632 318 - - [30]
1629 321 - 2 [30]
1622 328 - - [30]
1619 331 - 2 [30]
1610 340 - - [30]
1603 347 Template:Cvt - Approx 345 BP eruption - Oct 1603 Lake Lögurinn core[29]
1598 352 - 3 [30]
1530±10 420±10 - - [30]
1521 429 - - [30]
1510 440 - - Lake Lögurinn core.[29]
1508 442 Template:Cvt - Lake Lögurinn core.[29]
1500 450 - - Lake Lögurinn core.[29]
1500 450 - - [30]
1490±10 460±10 - - [30]
1471 479 - - [30]
1470±10 480±10 - - [30]
1469 481 - - [30]
1450±10 500±10 - - [30]
1430±10 520±10 - - [30]
1390±10 560±10 - - [30]
1370±10 580±10 - - [30]
1369 581 - - [30]
1354 596 - - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29][30]
1350 600 - - [30]
1341 609 - 2 [30]
1332 618 - 2 [30]
1310±10 640±10 - - [30]
1290±10 660±10 - - [30]
1270±10 680±10 - - [30]
1230±10 720±10 - - [30]
1190 760 - - [30]
1162 788 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29]
1090 860 - - [30]
1050 900 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29]
1010 940 - - [30]
977 973 Template:Cvt - Lake Lögurinn core. Has some Veidivötn-Bárdarbunga compositional characteristics - may be mixed eruption or mis–assigned.[29]
885 1065 - - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29]Template:Efn
858 1092 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]Template:Efn
853 1097 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]Template:Efn
852 1098 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29]Template:Efn
850 1100 Template:Cvt - Lake Lögurinn core. Has also Kverkfjöll, Veidivötn-Bárdarbunga compositional characteristics - may be mixed eruption or mis–assigned.[29]Template:Efn
781 1169 Template:Cvt - Greenland, Lake Lögurinn, Kárahnjúkar & Snæfell cores.[32]Template:Efn
753 1197 - - Greenland core[32]
502 1448 Template:Cvt - Lake Lögurinn, Kárahnjúkar cores.[29]
303 1647 Template:Cvt - Lake Lögurinn core.[29]
280 1670 Template:Cvt - Lake Lögurinn, Kárahnjúkar, Snæfell, Svartárkort & marine cores.[29]
216 1734 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29]
183 1767 Template:Cvt - Lake Lögurinn core.[29]
-1818±100 BCE 1968±100 Template:Cvt 2 [30]Lake Lögurinn core. Has some Veidivötn-Bárdarbunga compositional characteristics - may be mixed eruption or mis–assigned [29]
-589589 BCE 2539 Template:Cvt - Lake Lögurinn core.[29]
-800800 BCE 2750 Template:Cvt - Lake Lögurinn, Kárahnjúkar, Snæfell & marine cores.[29]
-834834 BCE 2784 Template:Cvt - Lake Lögurinn, Kárahnjúkar, Snæfell & marine cores.[29]
-19501950 BCE 3900 - 2 [30]
-24062406 BCE 4356 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]
-27012701 BCE 4651 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Snæfell cores.[29]
-33433343 BCE 5293 Template:Cvt - Lake Lögurinn core. Has some Kverkfjöll compositional characteristics - may be mixed eruption or mis–assigned.[29]
-36073607 BCE 5557 Template:Cvt - Lake Lögurinn core.[29]
-37113711 BCE 5661 Template:Cvt - Lake Lögurinn & Snæfell cores.[29]
-37453745 BCE 5695 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Snæfell cores. Has some Veidivötn-Bárdarbunga compositional characteristics - may be mixed eruption or mis–assigned.[29]
-41174117 BCE 6067 Template:Cvt - Lake Lögurinn, Kárahnjúkar, Snæfell & marine cores.[29]
-41874187 BCE 6137 Template:Cvt - Lake Lögurinn core. Trace possible in a Kárahnjúkar core.[29]
-42764276 BCE 6226 Template:Cvt - Lake Lögurinn. Possibly in a Kárahnjúkar core.[29]
-43334333 BCE 6283 Template:Cvt - Lake Lögurinn core. Possibly in a Kárahnjúkar core.[29]
-43384338 BCE 6288 Template:Cvt - Lake Lögurinn. Trace possible in a Kárahnjúkar core.[29]
-46744674 BCE 6624 - - Lake Lögurinn & Kárahnjúkar cores.[29]
-47384738 BCE 6688 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]
-48494849 BCE 6799 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]
-50735073 BCE 7023 Template:Cvt - Lake Lögurinn, Kárahnjúkar & Svartárkort cores.[29]
-57585758 BCE 7708 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]
-58305830 BCE 7780 - - Lake Lögurinn core.[29]
-58895889 BCE 7839 Template:Cvt - Lake Lögurinn & Kárahnjúkar cores.[29]
-62265889 BCE 8176 Template:Cvt - Lake Lögurinn core.[29]
-66926692 BCE 8642 Template:Cvt - Lake Lögurinn core.[29]
-66956695 BCE 8645 Template:Cvt - Lake Lögurinn core a possibly in Svartárkort core.[29]
-67166716 BCE 8666 Template:Cvt - Lake Lögurinn core.[29]
-68766876 BCE 8826 Template:Cvt - Lake Lögurinn core.[29]
-71087108 BCE 9058 Template:Cvt - Lake Lögurinn core.[29]
-71367136 BCE 9086 Template:Cvt - Lake Lögurinn core.[29]
-71627162 BCE 9112 Template:Cvt - Lake Lögurinn core.[29]
-71717171 BCE 9121 Template:Cvt - Lake Lögurinn & Svartárkort cores.[29]
-71807180 BCE 9130 Template:Cvt - Lake Lögurinn & Svartárkort cores[29]
-72347234 BCE 9184 Template:Cvt - Lake Lögurinn core.[29]
-73187318 BCE 9268 Template:Cvt - Lake Lögurinn core.[29]
-73947394 BCE 9344 Template:Cvt - Has some Veidivötn-Bárdarbunga compositional characteristics - may be mixed eruption or mis–assigned. Lake Lögurinn & Snæfell cores[29]
-74837483 BCE 9433 Template:Cvt - Lake Lögurinn core. Possibly in Snæfell core.[29] Tholeiite basalt G9410 tephra in Torfdalsvatn core dated at 9410 ± 340 BP.[33]
-75367536 BCE 9486 Template:Cvt - Lake Lögurinn core.[29]
-75777577 BCE 9527 Template:Cvt - Lake Lögurinn core.[29]
-75857585 BCE 9535 Template:Cvt - Lake Lögurinn core.[29]
-77037703 BCE 9653 Template:Cvt - Lake Lögurinn core.[29] Tholeiite basalt tephra G9630 in Torfdalsvatn core dated at 9630 ± 350 BP.[33] May be part of G10ka series tephra which covers a 500 year period.Template:Efn
-78267826 BCE 9776 Template:Cvt - Lake Lögurinn & Svartárkort cores[29] Tholeiite basalt tephra G9740 in Torfdalsvatn core dated at 9740 ± 320 BP.[33] May be part of G10ka series tephra which covers a 500 year period.Template:Efn
-78997899 BCE 9849 - - Lake Lögurinn & Kirkjugardur cores.[29] Tholeiite basalt tephra G9850 in Torfdalsvatn core dated at 9850 ± 300 BP.[33] May be part of G10ka series tephra which covers a 500 year period.Template:Efn
-79197919 BCE 9869 Template:Cvt - Lake Lögurinn, Svartárkort & Kirkjugardur cores.[29] May be part of G10ka series tephra which covers a 500 year period.Template:Efn
-80538053 BCE 10003 Template:Cvt - Lake Lögurinn core.[29] May be part of G10ka series tephra which covers a 500 year period.Template:Efn
-80698069 BCE 10019 Template:Cvt - Lake Lögurinn, Svartárkort & Kirkjugardur cores.[29] May be part of G10ka series tephra which covers a 500 year period.Template:Efn
-82488248 BCE 10198 - - Lake Lögurinn, Kirkjugardur cores.[29] May be part of G10ka series tephra which covers a 500 year period.Template:Efn Tholeiite basalt tephra in at least one of seven layers in Torfdalsvatn core.[33]
-82508250 BCE 10200 - 6 [30]Also has some Borrobol tephra like compositional characteristics - may be mixed eruption or mis–assigned. Lake Lögurinn, Svartárkort, Litligardur & Reitsvík cores and may be the Fosen tephra identified of same age in Fosen, Norway[29] Tholeiite basalt tephra in several of seven layers in Torfdalsvatn core.[33] May be part of G10ka series tephra which covers a 500 year period.Template:Efn

Bacteria in the subglacial lakes

In 2004, a community of bacteria was detected in water of the Grímsvötn lake under the glacier, the first time that bacteria have been found in a subglacial lake. The lakes never freeze because of the volcanic heat. The bacteria can also survive at low concentrations of oxygen. The site is a possible analogue for life on the planet Mars, because there are also traces of volcanism and glaciers on Mars and thus the findings could help identify how to look for life on Mars.[34][35]

Geology

There is the potential for mechanical interaction such as dyke propagation between Grímsvötn and Thordarhyrna.[36] Interactions can also occur with the nearby Bárðarbunga volcano, which is part of a separate volcanic system.[36] The volcano erupts predominantly tholeiitic basalt,[2] and a close chemical affinity exists with the other lavas of the Grímsvötn-Laki volcanic system.[37] The compositional separation from nearby systems has been studied in some detail, and is used to assign lava and tephra deposits to the volcanic system.[31][29] Some of the tephra's erupted have transpired to have mixed compositions with nearby volcanic systems and it is not known if this is due to dual eruptions or intusions crossing magma reserviors.[29] The volcanic system is part of the Eastern volcanic zone of Iceland, and is directly over the Iceland mantle plume.[38] The volcanic system has crater rows extending to the south east; the Template:Cvt long Laki–Grímsvötn fissure system and the Template:Cvt long Rauðhólar-Eldgígur fissure system.[37][2][4] The Rauðhólar-Eldgígur fissure system has been related by some authors to an alignment with the Thordarhyrna central volcano with the Laki–Grímsvötn more in alignment with the Grímsvötn central volcano.[31] Eruptives from Grímsvötn and Thordarhyrna are able to be geochemically distinguished between, so it is possible that the two central volcanoes are not one system.[39] Thordarhyrna has rhyolite formations which have not been found at Grímsvötn.[40]

Future trends

Studies indicate that volcanic activity in Iceland rises and falls so that the frequency and size of eruptions in and around the Vatnajökull ice cap varies with time. It is believed that the four eruptions between 1996 and 2011 could mark the beginning of an active period, during which an eruption in Grímsvötn in Vatnajökull may be expected every 2–7 years. Parallel volcanic activity in nearby Bárðarbunga is known to be associated with increased activity in Grímsvötn. Seismic activity has been increasing in the area in recent years, indicating the entry of magma.[41]

See also

Notes

Template:Notelist

References

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  1. ↑ Script error: No such module "citation/CS1".
  2. ↑ a b c d e f g Script error: No such module "citation/CS1".
  3. ↑ Script error: No such module "Citation/CS1".
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ Template:Cite thesis Template:Rp
  6. ↑ a b c d e Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ See eg.: Elín Margrét Magnúsdóttir: Gjóska úr Grímsvötnum 2011 og Bárðarbungu 2014-2015 : Ásýndar- ogkornastærðargreining. BS ritgerð. Jarðvísindadeild Háskóli Íslands (2017) (in Icelandic, abstract also in English) Retrieved 24 August 2020.
  10. ↑ See also: Anne Schöpa: Subglacial volcanism with examples from Iceland. TU Freiberg. (2008) Template:Webarchive
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Eldgos í Grímsvötnum Template:Webarchive, 24 May 2011 (in Icelandic)
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ a b Eurocontrol news
  18. ↑ Scottish flights grounded by Iceland volcanic ash cloud, BBC, 23 May 2011
  19. ↑ Iceland eruption hits Norwegian flights, The Foreigner, 23 May 2011
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".
  22. ↑ Script error: No such module "citation/CS1".
  23. ↑ Script error: No such module "citation/CS1".
  24. ↑ Script error: No such module "citation/CS1".
  25. ↑ Script error: No such module "citation/CS1".
  26. ↑ Script error: No such module "citation/CS1".
  27. ↑ Script error: No such module "citation/CS1".
  28. ↑ Script error: No such module "Citation/CS1".Template:Rp
  29. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj bk bl bm bn bo bp bq br Script error: No such module "Citation/CS1".Template:Rp
  30. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj bk bl bm bn bo Cite error: Script error: No such module "Namespace detect".Script error: No such module "Namespace detect".
  31. ↑ a b c d Script error: No such module "Citation/CS1".
  32. ↑ a b Cite error: Script error: No such module "Namespace detect".Script error: No such module "Namespace detect".
  33. ↑ a b c d e f Script error: No such module "Citation/CS1".
  34. ↑ Script error: No such module "Citation/CS1".
  35. ↑ Script error: No such module "Citation/CS1".
  36. ↑ a b Script error: No such module "Citation/CS1".
  37. ↑ a b Script error: No such module "Citation/CS1".Template:Rp
  38. ↑ Script error: No such module "Citation/CS1".Template:Rp
  39. ↑ Template:Cite thesisTemplate:Rp
  40. ↑ Script error: No such module "Citation/CS1".
  41. ↑ Script error: No such module "citation/CS1".

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External links

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