View source for Geysir

{{Short description|Geyser in Iceland}}
{{About||the ship of the same name|MV Geysir||Geyser (disambiguation)}}
{{use dmy dates|date=October 2022}}
{{Infobox landform
| name = Geysir 
| type = [[Geyser]]
| photo = Image:Erupting geysir.jpg
| photo_caption = The Great Geysir erupting in 2000
| elevation_m = 110
| elevation_ref = 
| map = Iceland
| map_relief = 1 
| map_caption = Location in [[Iceland]]
| label_position = none
| location = Southwestern Iceland
| coordinates = {{coord|64.3137|-20.2995|format=dms|display=inline,title|type:landmark_region:IS}} 
| volcanic_arc/belt =[[West volcanic zone of Iceland]] 
| last_eruption = 
}}
'''Geysir''' ({{IPA|is|ˈceiːsɪr̥|audio=Is-Geysir_pronunciation.ogg}}), sometimes known as '''The Great Geysir''', is a [[geyser]] in south-western [[Iceland]],{{sfn|Pasvanoglu|1998|p=285}} that geological studies suggest started forming about 1150 CE.{{sfn|Jones|Renaut|2021|loc=Conclusions}} The English word ''[[wiktionary:geyser|geyser]]'' (a periodically spouting [[hot spring]]) derives from Geysir.{{sfn|Pasvanoglu|1998|pp=282, 285}} The name ''Geysir'' itself is derived from the [[Icelandic language|Icelandic]] verb ''[[wiktionary:geysa|geysa]]'' ("to go quickly forward").<ref name=EB1911/> Geysir lies in the [[Haukadalur (Bláskógabyggð)|Haukadalur]] valley on the slopes of Laugarfjall lava dome, which is also the home to [[Strokkur]] geyser about {{convert|50|m}} to the south.{{sfn|Pasvanoglu|1998|pp=282, 285-6}} The Strokkur geyser may be confused with it, and the geothermal field it is in is known usually as either, Geysir or Haukadalur.

Eruptions at Geysir can typically hurl boiling water up to {{cvt|60|m}} in the air.{{sfn|Pasvanoglu|1998|p=285}} However, eruptions are nowadays infrequent, and have in the past stopped altogether for many years at a time.{{sfn|Pasvanoglu|1998|p=282}}

==History==
A geyser at the general site is described in a written source by [[Saxo Grammaticus]],<ref name=EB1911>{{Cite EB1911 |wstitle= Geyser |last= |first= |author-link= |volume= 11 |pages= 913-915 |short=1}}</ref> as a mention in [[Gesta Danorum]], his work finished about 1206 which was printed in 1514 as Danorum Regum heroumque Historiae.<ref>{{Cite EB9 |wstitle= Geysers |volume= X |pages=556-558 |short= 1}}</ref> However the oldest definitive accounts of the hot springs at Haukadalur in their present form, date back to 1294,{{sfn|Jones|Renaut|2021|loc=Age of Geysir}} in the chronicle "Oddaverjaannáll",{{sfn|Jones|Renaut|2021|loc=Introduction}} when earthquakes in the area caused significant changes in local neighbouring landscape, creating several new hot springs.{{sfn|Pasvanoglu|1998|p=282}} Changes in the activity of Geysir and the surrounding geysers are strongly related to [[earthquake]] activity.{{sfn|Pasvanoglu|1998|p=282}} In records dated 1630, the geysers erupted so violently that the valley around them trembled.{{sfn|Pasvanoglu|1998|p=282}} The name "Geysir" was first mentioned in written sources in 1647;{{sfn|Jones|Renaut|2021|loc=Introduction}} as unusual natural phenomena were of great interest during the [[Age of Enlightenment]], the term became popular and has been used for similar hydrothermal features worldwide since then.
[[File:BLAKE(1873) p06 The Great Geysir.jpg|thumb|upright|1873 drawing of Geysir]]
In 1809 and 1810 the eruptions were about every 30 hours and up to {{cvt|30|m}} high.<ref name=EB1911/> In 1811 [[Sir George Mackenzie, 7th Baronet|George Mackenzie]], a geologist, first proposed that expansion of steam in a subsurface cavity explained Geysir's activity.{{sfn|Hurwitz|Manga|2017|loc=4.1. Subsurface Processes}} In 1845, it reached a height of {{cvt|170|m}}.{{Citation needed|reason=This claim needs a reliable source; Bunsden works do not appear to validate - reliable source is likely to be in Danish or German giving scientific studies sponsored at the time.|date=February 2024}} In 1846, research on Geysir, and Iceland sponsored by the [[Christian VIII of Denmark|Danish Crown]], by amongst others, the German [[chemist]] [[Robert Bunsen]], resulted in a better general explanation of the mechanism of geyser activity which contributed significantly to the more refined models used today.{{sfn|Pasvanoglu|1998|p=287}}<ref name=EB1911/> Measurements by Professor Bunsen in that year showed that Geysir was erupting {{cvt|45|-|54|m}} high.

In 1882 an account of the first accurate survey (previous attempts were associated with instrument problems), noted that a booming sound warned or Geysir's eruptions, eruptions were about 6 hourly but often of only {{cvt|5|ft}}.{{sfn|Peek|1882|p=132}}

The records of recent centuries show that earthquakes have tended to revive the activity of Geysir, which then subsided again in the following years.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=4.2. Implications}}  Before 1896, Geysir was almost dormant.{{sfn|Pasvanoglu|1998|p=282}} In that year an earthquake caused eruptions to begin again, occurring several times a day, lasting up to an hour and causing spouts of up to {{cvt|70|-|80|m}} in height.{{sfn|Pasvanoglu|1998|p=286}} In 1910, it was active every 30 minutes; by 1915, the time between the eruptions was as much as six hours, and in 1916, the eruptions all but ceased. In 1935, a man-made channel was dug through the [[silica]] rim around the edge of the geyser vent.{{sfn|Pasvanoglu|1998|p=282}} This [[ditch]] caused a lowering of the [[water table]] and a revival in activity.{{sfn|Pasvanoglu|1998|p=282}} Gradually this channel also became clogged with silica and eruptions again became rare.{{sfn|Pasvanoglu|1998|p=282}}

In 1981, the ditch was cleared again and eruptions could be stimulated, on special occasions, by the addition of [[soap]].{{sfn|Pasvanoglu|1998|p=282}} Due to environmental concerns, soap was seldom added during the 1990s. During that time, Geysir seldom erupted. When it did erupt, it was spectacular, sending boiling water sometimes up to {{convert|70|m}} into the air. On the [[Icelandic National Day]], authorized government geologists would force an eruption. Further earthquakes in 2000 revived the geyser,{{sfn|Stefánsson|Guðmundsson|Halldórsson|2000}} and it reached 122 meters for two days.{{Citation needed|reason=This claim needs a reliable source; see Talk.|date=July 2011}}, thus becoming one of the highest known geysers in history. [[Waimangu Geyser]] in [[New Zealand]] typically erupted higher than this, up to {{cvt|460|m}} high,<ref>{{cite encyclopaedia|first1 =C.|last1 =Stewart|title ='Hot springs, mud pools and geysers - Geysers', Te Ara - the Encyclopedia of New Zealand|url =https://www.TeAra.govt.nz/en/photograph/6497/waimangu-geyser-the-worlds-largest |access-date= 1 February 2024}}</ref> but it stopped all activity around 1908.{{sfn|Hurwitz|Manga|2017|loc=4.2. Surface Eruption}}<ref>Glennon, J Allan [http://www.uweb.ucsb.edu/~glennon/geysers/world.htm "World Geyser Fields"] {{webarchive|url=https://web.archive.org/web/20070630141427/http://www.uweb.ucsb.edu/~glennon/geysers/world.htm |date=2007-06-30 }} Retrieved on 2008-04-04</ref> Initially, Geysir eruptions were taking place on average eight times a day. By July 2003, this activity had again decreased to around three times per day. Large eruptions after this became so rare that one in 2016 was considered newsworthy.<ref>{{cite news|url=https://icelandmonitor.mbl.is/news/nature_and_travel/2016/02/21/rare_eruption_of_iceland_s_most_famous_hot_spring_g/|title=Rare eruption of Iceland's most famous hot spring Geysir|date =19 April 2016|archive-date=27 April 2016| archive-url=https://web.archive.org/web/20160427185308/https://icelandmonitor.mbl.is/news/nature_and_travel/2016/02/21/rare_eruption_of_iceland_s_most_famous_hot_spring_g/}}</ref>

==Geology==
{{maplink|frame=yes|frame-align=right|frame-width=252|frame-height=350|frame-long=-20.3050|frame-lat=64.3118|zoom=14|raw={{Wikipedia:Map data/Geysir}}
|text=Approximate map of:{{legend|#f9dbd8|Surface thermal features of Haukadalur valley geothermal area as of 2016}}{{legend|#f0e2d8|Laugarfjall lava dome}}{{legend|#0000ff|Selected geothermal features}}Mouse over is enabled on clicking the map.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=Fig. 5.}} 
}}

A current geological definition of a hot water geyser is "''…a hot spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapor phase''"{{sfn|Jones|Renaut|2021|loc=Introduction}} which is a technical correction of historic definitions that mention steam and a column in air.<ref name=EB1911/> Geysir is technically a hot water pool geyser rather than a cone geyser so much heat is lost to the atmosphere explaining why the maximum temperature in its conduit is several meters below the top of the water column rather than at the top like is the case with [[Old Faithful]].{{sfn|Hurwitz|Manga|2017|loc=4.1. Subsurface Processes}} Geysir's funnel like surface conduit has a diameter of between {{convert|0.4|-|1.0|m|abbr=on}} and until a narrow constriction a depth of about {{convert|23|m|abbr=on}}.{{sfn|Hurwitz|Manga|2017|loc=2. Geography and Geology of Geysers}} In the conduit above {{cvt|10|m}} the geyser has a temperature between {{cvt|85|–|95|C}} and reaches higher temperatures of about {{cvt|120|C-change|0}} below this.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=Fig. 5.}} The conduit in this higher temperature region is more constricted and irregular than earlier studies could ascertain, and fracture related, with potential for the boiling temperature to be reached.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=Fig. 5.}} Below {{cvt|16|m}} the conduit has several branches and cavities.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=5. Conclusions}} As it is closer to sea level than most of the world's 1000 odd geysers the actual erupted water temperature is higher than most.{{sfn|Hurwitz|Manga|2017|loc=Figure 1b}}

The {{cvt|3|km2}} Haukadalur volcanic system, which provides the heat,{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=1. Background}} is mainly to the west of Geysir but has not been active volcanically for over 10,000 years.{{sfn|Pasvanoglu|1998|p=283}} Geysir is on the eastern slopes of the [[rhyolite|rhyolitic]] Laugarfjall lava dome,{{sfn|Pasvanoglu|1998|pp=282-3}} but the [[hyaloclastite]] nature of the rock that the water erupts through, may be important in its fracture network.{{sfn|Hurwitz|Manga|2017|loc=2. Geography and Geology of Geysers}} It is now known that the areas of thermal activity of the geothermal field align along microfractures that became seismologically active after the [[2000 Iceland earthquakes]].{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=1. Background, 5. Conclusions}}

The geothermal water source may be the southern [[Langjökull]] ice sheet, about {{cvt|50|km}} to the north.{{sfn|Jones|Renaut|2021|loc=Geology setting}}

Research on the deposits of [[Siliceous sinter|sinter]], formed from the dissolved minerals in the hot water, shows that hot springs at the Geysir location have been active for approximately 10,000 years.{{sfn|Jones|Renaut|Torfason|Owen|2007|p=1241}} However before Geysir became active as a definitive geyser the previous deposits were covered with [[tephra]] from [[Katla (volcano)|Katla]] and [[Hekla]], and little sinter was deposited for about 2000 years.{{sfn|Jones|Renaut|Torfason|Owen|2007|p=1241}} Once Geysir became active, precipitation of [[opal]] from the geothermal water lead to a [[siliceous sinter]] apron around the geyser.{{sfn|Jones|Renaut|2021|loc=Abstract}} This has allowed formation of the modern geyser to be dated to about 1150 CE which accords with the history of written mention above.{{sfn|Jones|Renaut|2021|loc=Conclusions}}

==Nearby Geysers==
[[File:Litli Geysir, Área geotérmica de Geysir, Suðurland, Islandia, 2014-08-16, DD 112.JPG|thumb|Little Geysir]]
The nearby geyser [[Strokkur]] erupts much more frequently than Geysir, erupting to heights of up to {{convert|35|m}} every few minutes.{{sfn|Pasvanoglu|1998|p=286}} Strokkur was first described in 1789.<ref name=EB1911/> There is contrast in its lack of warning of eruption with the case of Geysir and evidence that the plumbing might not be totally independent.{{sfn|Peek|1882|p=132}} Strokkur's conduit has also been mapped in detail and is pipe shaped to {{cvt|8|m}}, where it narrows before expanding into a cavity at about {{cvt|11|m}} before narrowing again into a fracture configuration at about {{cvt|13|m}} where temperatures become close to the boiling point.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=Fig. 5.}} Strokkur's activity has also been affected by earthquakes, although to a lesser extent than the Great Geysir.{{sfn|Pasvanoglu|1998|p=286}} Due to its eruption frequency, online photos and videos of Strokkur are regularly mislabelled as depicting Geysir. There are around thirty much smaller geysers and [[Hot spring|hot pools]] in the area, including one called Litli Geysir ('Little Geysir').{{sfn|Pasvanoglu|1998|p=282-3}} Detailed thermal mapping of the geothermal field has revealed 364 distinct hot areas.{{sfn|Walter|Jousset|Allahbakhshi|Witt|2020|loc=Abstract}}

Descriptions of the Great Geysir and Strokkur have been given in many travel guides to Iceland published from the 18th century onwards. Together with [[Þingvellir]] and the [[Gullfoss]] waterfall, they are part of the ''[[Golden Circle (Iceland)|Golden Circle]]'', the most famous tourist route in the country.

Geysir was officially protected by the [[Ministry for the Environment and Natural Resources (Iceland)|Ministry for the Environment and Natural Resources]] on 17 June 2020.<ref>{{Cite news|url=https://icelandmonitor.mbl.is/news/nature_and_travel/2020/06/21/geysir_area_declared_protected/|title=Geysir Area Declared Protected|date=21 June 2020|access-date=31 January 2024|author=Vala Hafstað|language=en|archive-url=https://web.archive.org/web/20231002142424/https://icelandmonitor.mbl.is/news/nature_and_travel/2020/06/21/geysir_area_declared_protected/|archive-date=2 October 2023}}</ref>

==Ownership of the area==
Until 1894, the Geysir area was owned by local farmers.<ref name=landowership>{{cite news|url=https://www.icelandreview.com/news/historian-explains-why-icelandic-government-owns-geysir/ |title=Historian Explains Why Icelandic Government Owns Geysir |access-date =31 January 2024|date =2 April 2014|archive-url=https://web.archive.org/web/20220925025648/https://www.icelandreview.com/news/historian-explains-why-icelandic-government-owns-geysir/|archive-date=25 September 2022}}</ref> In that year the area was sold to [[James Craig, 1st Viscount Craigavon|James Craig]] (later [[Viscount Craigavon|Lord Craigavon]]), a [[whiskey]] distiller from [[Ulster]] and a future [[Prime Minister of Northern Ireland]].<ref name=landowership /><ref name=IR>{{cite news|url =https://www.icelandreview.com/news/geysir-soon-be-bought/|title =Geysir Soon To Be Bought|access-date =31 January 2024|date =25 August 2017|archive-url=https://web.archive.org/web/20240131195956/https://www.icelandreview.com/news/geysir-soon-be-bought/|archive-date=31 January 2024}}</ref> Initially, he erected large fences around the site and an entrance fee was charged for visitors wishing to view the geysers.<ref name=landowership /> The following year, he gave the area as a present to a friend, E. Craig, who dropped the entrance fees. Later Craig's nephew Hugh Rogers inherited the site.<ref name=IR /> In 1935, he sold the site to film director [[Sigurður Jónasson]] who subsequently donated it to the Icelandic people in perpetuity,<ref name=landowership /> although full public ownership of all routes of access did not take place until 2017.<ref name=IR />

==Gallery==
<gallery mode="packed">
File:Great Geysir (4).jpg|The erupting Great Geysir in summer 2009
Image:Litli Geysir.jpg|Litli Geysir erupting
File:Gran Geysir, Área geotérmica de Geysir, Suðurland, Islandia, 2014-08-16, DD 107.JPG|Geysir in 2014
Image:Geysir forest.jpg|A forest near the Geysir
File:PSM V21 D387 Theoretical structure of the bjarnafell great geyser.jpg|Diagram of a theoretical structure for Geysir, from 1882
</gallery>

==See also==
* [[Strokkur]]
* [[Volcanism of Iceland]]

==References==
{{Reflist}}

=== Sources ===
*{{cite book|last1 =Pasvanoglu|first1 =S.|title=Geothermal Training Programme Reports 1998|year =1998|chapter =Geochemical study of the Geysir geothermal field in Haukadalur, S-Iceland|pages =281–318|publisher =United Nations University|chapter-url=https://www.researchgate.net/profile/Suzan-Pasvanoglu/publication/292227219_Geochemical_study_of_the_Geysir_geothermal_field_in_Haukadalur_S-Iceland/links/6149df7ba3df59440b9fcc59/Geochemical-study-of-the-Geysir-geothermal-field-in-Haukadalur-S-Iceland.pdf |editor-last1 =Pasvanoglu|editor-first1 =S.|editor-last2 =Kristmannsdóttir|editor-first2 =H.|editor-last3 =Björnsson|editor-first3=S.|editor-last4 =Torfason|editor-first4 = H.|access-date=29 January 2024}}
*{{cite journal|title =The geological history of Geysir, Iceland: a tephrochronological approach to the dating of sinter|first1 =B.|last1 =Jones|first2 =R.W.|last2 =Renaut|first3 =H.|last3 =Torfason|first4 =R.B.|last4 =Owen|journal =Journal of the Geological Society|year=2007|volume =164|issue =6|pages=1241–1252|doi =10.1144/0016-76492006-178}}
*{{cite journal|first1 =B.|last1 =Jones|first2 =R.W.|last2 =Renaut|title =Multifaceted incremental growth of a geyser discharge apron – Evidence from Geysir, Haukadalur, Iceland|journal =Sedimentary Geology|volume =419|year =2021|article-number=105905|issn =0037-0738|doi =10.1016/j.sedgeo.2021.105905}}
*{{cite journal|title =Across Iceland by the Sprengisandr Route|journal=Proceedings of the Royal Geographical Society and Monthly Record of Geography|year =1882|last1 =Peek|first1 =C.E.|pages =129–140|volume =4}}
*{{cite journal|title =The Fascinating and Complex Dynamics of Geyser Eruptions.|first1 =S.|last1 =Hurwitz|first2 =M.|last2 =Manga|journal =Annual Review of Earth and Planetary Sciences|year =2017|volume=45|issue =1|pages=31–59|doi =10.1146/annurev-earth-063016-015605}} 
*{{cite report|last1 =Stefánsson|first1 =R.|last2 =Guðmundsson|first2 =G.B.|last3 =Halldórsson|first3= P.|year= 2000|url =https://m.vedur.is/media/vedurstofan/utgafa/greinargerdir/2000/00010.pdf|access-date=3 February 2024|archive-date=25 January 2022|archive-url=https://web.archive.org/web/20220125154444/https://m.vedur.is/media/vedurstofan/utgafa/greinargerdir/2000/00010.pdf|title =The two large earthquakes in the South Iceland seismic zone on June 17 and 21, 2000. Veðurstofa Íslands}}
*{{cite journal|last1 =Walter|first1 =T.R.|last2 =Jousset|first2 =P.|last3 =Allahbakhshi|first3 =M.|last4 =Witt|first4 =T.|last5= Gudmundsson|first5 =M.T.|last6 =Hersir|first6 =G.P.|year =2020|title =Underwater and drone based photogrammetry reveals structural control at Geysir geothermal field in Iceland|journal =Journal of Volcanology and Geothermal Research|volume =391|page=106282|bibcode =2020JVGR..39106282W|doi =10.1016/j.jvolgeores.2018.01.010}}<!-- {{snf|Walter|Jousset|Allahbakhshi|Witt|2020}}--->

==Further reading==
* ''The Great Geysir'', Helgi Torfason of the Icelandic National Energy Authority, 1985 (no ISBN, but book available from the Geysir tourist center).

==External links==
{{Commons category-inline|Great Geysir}}
* [https://web.archive.org/web/20070503011325/http://www.geysircenter.com/english/geysirarea.html ''Information and photos of Geysir and the geothermal area'']
* Photos: [http://icelandiscool.com/geysir/][https://web.archive.org/web/20040506201520/http://www.islandsmyndir.is/html_skjol/sudurland/geysir/forsida_geysir_1.htm][http://www.eldey.de/English/gallery/gallery2/gallery2.html]
* Videos: [http://myicelandjournal.blogspot.com/2007/09/day-4-geysir-gullfoss-and-vik.html ''Iceland Travel Journal by Keith Chan'']
* {{cite gvp|name=Geysir|vn=371803|access-date=2021-06-25}}

{{Authority control}}

[[Category:Southern Region (Iceland)]]
[[Category:Geysers of Iceland]]
[[Category:Volcanic systems of Iceland]]
[[Category:West Volcanic Zone of Iceland]]
[[Category:Pleistocene volcanoes]]