View source for Volcanism of Iceland

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:''The volcano system in Iceland that started activity on August 17, 2014, and ended on February 27, 2015, is [[2014–2015 eruption of Bárðarbunga|Bárðarbunga]].''
:''The volcano in Iceland that erupted in May 2011 is [[2011 eruption of Grímsvötn|Grímsvötn]].''
[[Image:Volcanic system of Iceland-Map-en.svg|thumb|220px|Active volcanic areas and systems in Iceland]]
[[File:Outline of Iceland Deformation and Volcanic Zones.svg|thumb|220px|Volcanic and transform zones of Iceland {{collapsible list|title=Legend:|RR, Reykjanes Ridge|RVB, Reykjanes Volcanic Belt|WVZ, West Volcanic Zone|MIB, Mid-Iceland Belt|SISZ, South Iceland Seismic Zone|EVZ, East Volcanic Zone|SIVZ, South Iceland Volcanic Zone|NVZ, North Volcanic Zone|TFZ, Tjörnes Fracture Zone|KR, Kolbeinsey Ridge|ÖVB, Öræfajökul Volcanic Belt|VB, Snæfellsnes Volcanic Belt}}]]
{{Location map+|Iceland|width=220|float=right|alt=Some volcanoes of Iceland |caption=Volcanoes and volcanic systems in Iceland with Wikipedia articles {{collapsible list|title=Key:|1) [[Snæfellsjökull]]|2) [[Ljósufjöll]]|3) [[Reykjanes#Reykjanes volcanic system|Reykjanes]]|4) [[Eldvörp–Svartsengi|Svartsengi]]|5) [[Fagradalsfjall]]|6) [[Krýsuvík (volcanic system)|Krýsuvík]]|7) [[Brennisteinsfjöll]]|8) [[Hengill]]|9) [[Surtsey]]|10) [[Eldfell]]|11) [[Eyjafjallajökull]]|12) [[Hekla]]|13) [[Katla volcano|Katla]]|14) [[Lakagigar]]|15) [[Öræfajökull]]|16) [[Grímsvötn]]|17) [[Bárðarbunga]]|18) [[Hofsjökull]]|19) [[Langjökull]]|20) [[Askja]]|21) [[Krafla]]|22) [[Theistareykjarbunga|Þeistareykjabunga]]}}|places=

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{{maplink|frame=yes|frame-align=right|frame-width=220|frame-height=220|frame-long=-19.3|frame-lat=64.76|zoom=5|raw=[{{Wikipedia:Map data/Askja}},{{Wikipedia:Map data/Grímsvötn}},{{Wikipedia:Map data/Öræfi volcanic belt}},{{Wikipedia:Map data/Hofsjökull}},{{Wikipedia:Map data/Katla}},{{Wikipedia:Map data/Hengill}},{{Wikipedia:Map data/Snæfellsnes volcanic belt}}]
|text=Outlines of [[central volcano]]es in Iceland. {{Wikipedia:Map data/Askja/key}}}}
[[Iceland]] experiences frequent [[volcano|volcanic]] activity, due to its location both on the [[Mid-Atlantic Ridge]], a divergent [[Plate tectonics|tectonic plate boundary]], and being over a [[Hotspot (geology)|hotspot]]. Nearly thirty volcanoes are known to have erupted in the [[Holocene epoch]]; these include [[Eldgjá]], source of the largest lava eruption in human history. Some of the various eruptions  of lava, gas and ash have been both destructive of property and deadly to life over the years, as well as disruptive to local, European, and international air travel.

==Volcanic systems and volcanic zones of Iceland==
[[Holocene]] volcanism in Iceland is mostly to be found in the ''Neovolcanic Zone'', comprising the [[Reykjanes volcanic belt]] (RVB), the [[West volcanic zone of Iceland|West volcanic zone]] (WVZ), the [[Geological deformation of Iceland#mid-Iceland belt|Mid-Iceland belt]] (MIB), the [[East volcanic zone of Iceland|East volcanic zone]] (EVZ) and the [[North volcanic zone of Iceland|North volcanic zone]] (NVZ). Two lateral volcanic zones play a minor role: [[Öræfajökull|Öræfi volcanic belt]] (ÖVB also known as Öræfajökull volcanic system) and [[Snæfellsjökull|Snæfellsnes volcanic belt]] (SVB).<ref>Thor Thordarson, Armann Hoskuldsson: ''Iceland. Classic geology of Europe 3.'' Harpenden 2002, p. 9</ref> Outside of the main island are the [[Reykjanes Ridge]] (RR), as part of the [[Mid-Atlantic Ridge]] to the south-west and the [[Kolbeinsey Ridge]] (KR) to the north. Two transform zones are connecting these volcano-tectonic zones: the [[South Iceland seismic zone]] (SISZ) in the south of Iceland and the [[Tjörnes transform zone]] (TFZ) in the north.

The island has around 30 [[active volcano|active volcanic]] systems. Within each are volcano-tectonic fissure systems and many, but not all of them, also have at least one [[central volcano]] (mostly in the form of a [[stratovolcano]], sometimes of a [[shield volcano]] with a [[magma chamber]] underneath). Several classifications of the systems exist, for example there is one of 30 systems,<ref name=Andrews2008>{{cite thesis|url=http://deposit.ddb.de/cgi-bin/dokserv?idn=991146220&dok_var=d1&dok_ext=pdf&filename=991146220.pdf |title=PhD Dissertation: Volcanotectonic Evolution and Characteristic Volcanism of the Neovolcanic Zone of Iceland |access-date=2011-05-24 |archive-url=https://web.archive.org/web/20120309212602/http://deposit.ddb.de/cgi-bin/dokserv?idn=991146220&dok_var=d1&dok_ext=pdf&filename=991146220.pdf |archive-date=2012-03-09 |publisher =Georg-August-Universität, Göttingen|first1 = R. E. B.|last1= Andrew|year =2008|pages=1–122}}</ref>{{rp|10}} and one of 34 systems, with the later currently being used in Iceland itself.<ref name=EIV>{{cite web|url =https://icelandicvolcanoes.is|title =Catalogue of Icelandic Volcanoes|access-date =13 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019}}</ref> There are 23 central volcanoes using the definition that they: erupt frequently;  extrude either [[basalt]]ic, intermediate or [[felsic]] <!--reference used term acid which is long depreciated as vague by most volcanologists--->lavas; have an associated shallow crustal magma chamber, and are often associated with collapse caldera or fissure systems.<ref name=Andrews2008/>{{rp|11}} Shield volcanoes, as the term is used in the Iceland context, tend to erupt only once, so have [[Monogenetic volcanic field|monogenetic]] characteristics. However many shield volcanoes outside Iceland are associated with oceanic island volcanism such as in [[Hawaii]] where they have been built up over many eruptions.<ref name=Andrews2008/>{{rp|pp=11–12}} [[Fissure vent]]s in Iceland tend to produce calmer effusive eruptions, but can be associated with large volumes of lava ([[flood basalt]] events) and some have had prolonged eruptions with numerous eruptive episodes, lasting for years.<ref name=Andrews2008/>{{rp|pp=12–13}}

Up to 2008, thirteen of the volcanic systems had hosted eruptions since the [[History of Iceland|settlement of Iceland]] in AD 874.<ref name=Thordarson2008>{{cite journal|last1=Thordarson|first1=T.|last2=Hoskuldsson|first2=A. |title=''Postglacial Volcanism in Iceland'' |url=http://pages.mtu.edu/~raman/papers2/Thordarson%20and%20Hoskuldsson%202008%20Postglacial%20volcanism.pdf |journal=Jökull|year=2008|volume=58|pages=197–228|doi=10.33799/jokull2008.58.197 }}</ref> Nearly thirty volcanoes are known to have erupted in the [[Holocene epoch]] and so are active.<ref>{{cite web |url=https://volcano.si.edu/list_volcano_holocene.cfm |title = Global Volcanism Program {{!}} Holocene Volcano List}}</ref>

Of these active volcanic systems, the most active is [[Grímsvötn]].<ref name=Gudmundsson2008>{{cite journal|last=Gudmundsson|first=Magnus Tumi|author2=Larsen, G |author3=Hoskuldsson, A |author4= Gylfason, A.G. |title=''Volcanic Hazards in Iceland''|journal=Jökull|year=2008|volume=58|pages=251–268|doi=10.33799/jokull2008.58.251 }}</ref>  Over the past 500&nbsp;years, Iceland's volcanoes have produced a third of the total global [[lava]] output.<ref>{{cite book
  | last = Waugh
  | first = David
  | author-link = David Waugh (geographer)
  | title = ''Geography: An Integrated Approach''
  | publisher = [[Nelson Thornes]]
  | location = United Kingdom
  | year = 2002
  | page = 16
  | isbn = 978-0-17-444706-1 }}</ref> Current productivity, which is known to be cyclical, has been estimated to be between {{cvt|0.05|-|0.08|km3}} per year which is higher than the output rate of the Hawaiian volcanoes, and would be double or even triple this figure if intrusive volumes are included.<ref name=Thordarson2008/>{{rp|205}}

===Volcano tectonics===
The types of eruptions most likely in a particular Icelandic volcanic system or zone are now understood. Earthquakes and volcanism have patterns in time and place that can be combined into a consistent tectonic process that is explained by the [[geological deformation of Iceland]]. In summary in Iceland there are four main types of tectonic zones:<ref name=Sæmundsson2020>{{cite journal|last1 =Sæmundsson|first1 =K.|last2 =Sigurgeirsson|first2 =M.Á.|last3 =Friðleifsson|first3 =G.Ó.|year =2020|title =Geology and structure of the Reykjanes volcanic system, Iceland|journal =Journal of Volcanology and Geothermal Research|volume =391|number =106501|doi =10.1016/j.jvolgeores.2018.11.022|bibcode =2020JVGR..39106501S}}{{rp|loc=Introduction}}</ref>
#Spreading zones of rifting and volcanism producing the predominant Iceland [[Tholeiitic magma series|tholeiitic basaltic]] crust
#Fracture zones connecting offset branches of the spreading zones which includes the SISZ
#Trans-tensional zones with transform faulting and spreading of which are the RVB and TFZ
#Flank zones with stratovolcanoes and minor rifting with alkalic to transitional volcanic rocks over the crust
These tectonic zones result from the interaction of combination of the spreading activity of the Mid-Atlantic Ridge which is spreading in a general east and west direction while the [[mantle plume]] activity that results in the hotspot, has been migrating over at least the last 25 million years in a west to slightly south-east direction.<ref name=Andrews2008/>{{rp|pp=4–6}}

== Geology ==

===Morphology ===
Fissure vents are found predominantly in what are termed fissure swarms (a combination of tectonic related fissures and faults) that are also associated with crater rows and smaller [[Cinder cone|cinder]] or [[spatter cone]]s.<ref name=EIVREY>{{cite web|url =https://icelandicvolcanoes.is/?volcano=REY|title =Catalogue of Icelandic Volcanoes - Reykjanes and Svartsengi volcanic systems |access-date =3 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Sigurgeirsson|first1 =Magnús Á.|first2 =Sigmundur|last2 =Einarsson}}{{rp|loc=Detailed Description}}</ref>  Where such eruptions interact with water the eruptions become more explosive and these [[phreatomagmatic eruption]]s produce tephra and possibly [[maar]]s and [[phreatomagmatic eruption#Surface features|tuff rings or cone]]s.<ref name=Sæmundsson2020/><ref name=EIVREY/>

=== Composition ===
The composition of the lava reflects the tectonic factors above and are consistent with the influence of the hotspot so the trend is for [[ocean island basalt]]s (OIB) type to predominate over [[Mid-ocean ridge#volcanism|mid ocean ridge basalts (MORB)]] which are only found in the north of the NVZ.<ref name=Jakobsson2008>{{cite journal|last1 =Jakobsson|first1 =S.P.|last2 =Jónasson|first2 =K.|last3 =Sigurdsson|first3 =I.A.|year =2008|title =The three igneous rock series of Iceland|journal= Jökull|volume =58|issue =1|pages =117–138|doi =10.33799/jokull2008.58.117|url =https://jokull.jorfi.is/articles/jokull2008.58/jokull2008.58.117.pdf|access-date=7 May 2024}}</ref>{{rp|pp=133-4}}  The compositional series are thus [[tholeiitic basalt]], transitional alkalic basalts and alkalic (felsic).<ref name=Jakobsson2008/>{{rp|pp=134}}

Large extrusive, predominantly [[Tholeiitic magma series|tholeiitic basaltic]] lava fields and shields with theoleiitic lava are the predominant material erupted and are found in the RVB, WVZ, MIB, EVZ and NVZ.<ref name=EIV/> They are associated with divergence tectonics of the ridge plate boundaries.<ref name=Sæmundsson2020/>{{rp|40}} Central volcanoes, with associated fissure swarms are typical, except in the RVB. [[Hengill]] is the only active central volcano in the far east of the RVB, and this is likely to be because here a [[triple junction]] exists, resulting in a volcano with some [[rhyolite|rhyolytic]] and [[dacite]] components due to the complexity of its rift propagation formation.<ref name=Kristján2019>{{cite web|url =https://icelandicvolcanoes.is/?volcano=HEN|title =Catalogue of Icelandic Volcanoes - Hengill|access-date =30 December 2023| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Kristján|first1 =Sæmundsson}}</ref><ref>{{Cite journal|first1= J. |last1= Decriem|first2= T. |last2= Árnadóttir|first3= A. |last3= Hooper|first4= H. |last4= Geirsson|first5= F. |last5= Sigmundsson|first6= M. |last6= Keiding|first7= B. G. |last7= Ófeigsson|first8= S. |last8= Hreinsdóttir|first9= P. |last9= Einarsson|first10= P. |last10= LaFemina|first11= R. A. |last11= Bennett|date= 2010|title= The 2008 May 29 earthquake doublet in SW Iceland|journal= [[Geophysical Journal International]]|volume= 181 | issue= 2 | pages= 1128–1146 |doi= 10.1111/j.1365-246x.2010.04565.x|bibcode= 2010GeoJI.181.1128D|doi-access= free}}</ref>{{rp|p=1128}} The island of [[Eldey]] off the south-west of the RVB has similar geological formations to the RVB but has a basalt composition with tholeiites and [[Picrite basalt|picrite]]s.<ref name=EIVELD>{{cite web|url =https://icelandicvolcanoes.is/?volcano=ELD|title =Catalogue of Icelandic Volcanoes - Eldey |access-date =3 January 2023| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|first1 =Guðrún|last1 =Larsen}}{{rp|loc=Detailed Description}}</ref> [[Hofsjökull]], a large volcano with a caldera and rhyolite lavas in the MIB has explosive eruption potential but has not erupted underneath its ice cover for several thousand years and its companion Kerlingarfjöll for even longer.<ref name=Grönvold2019>{{cite web|url =https://icelandicvolcanoes.is/?volcano=HOF|title =Catalogue of Icelandic Volcanoes - Hofsjökull|access-date =4 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Grönvold |first1 =Karl}}</ref>

[[Volcanic arc|Arc volcanism]] has been thought to be occurring in the Snæfellsnes volcanic belt with [[alkaline magma series]] volcanism in the stratovolcanoes such as [[Snæfellsjökull]] which usually erupt effusive basaltic lava but can have infrequent explosive silicic eruptions followed by extrusion of intermediate composition lava.<ref name=Jóhannesson2019>{{cite web|url =https://icelandicvolcanoes.is/?volcano=SNJ|title =Catalogue of Icelandic Volcanoes - Snæfellsjökull|access-date =3 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Jóhannesson|first1 =Haukur}}</ref> However the modelling of the processes involved is incomplete and almost certainly involves primarily fractional crystallization of primary basaltic magma with limited input from pre-existing crustal material as is the case in arc volcanism.<ref name=Banik2021>{{cite journal|last1 =Banik|first1 =T.J.|last2 =Carley|first2 =T.L.|last3 =Coble|first3 =M.A.|last4 =Hanchar|first4 =J.M.|last5 =Dodd|first5 =J.P.|last6 =Casale|first6 =G.M.|last7 =McGuire|first7 =S.P. =|year =2021|title =Magmatic processes at Snæfell volcano, Iceland, constrained by zircon ages, isotopes, and trace elements|journal =Geochemistry, Geophysics, Geosystems|volume =22|issue =3|page =p.e2020GC009255|doi =10.1029/2020GC009255|bibcode =2021GGG....2209255B}}</ref> The ÖVB is represented by the [[Öræfajökull]] (Hnappafellsjökull) stratovolcano which has a history of  violent rhyolite to alkali basalt eruptions with tephra volumes up to {{cvt|10|km3|abbr=on}} and accompanying [[jökulhlaup]].<ref name=EIVORA>{{cite web|url =https://icelandicvolcanoes.is/?volcano=ORA|title =Catalogue of Icelandic Volcanoes - Öræfajökull|access-date =3 January 2023| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|first1 =Ármann |last1 =Höskuldsson}}</ref>

The island [[Vestmannaeyjar]] volcano to the southwest of Iceland has in its recent activity formed the island of [[Surtsey]] and cones such as [[Eldfell]] on [[Heimaey]]. It is the southern tip of the EVZ propagating rift in what is an off rift region called the South Iceland Volcanic Zone (SIVZ),<ref>{{cite journal|first1 =M|last1 =Kahl|first2 =E.|last2 =Bali|first3 =G.H.|last3 =Guðfinnsson|first4 =D.A.|last4 =Neave|first5 =T.|last5 =Ubide|first6 =Q.H.A.|last6 =van der Meer|first7 =S. |last7 =Matthews|title =Conditions and Dynamics of Magma Storage in the Snæfellsnes Volcanic Zone, Western Iceland: Insights from the Búðahraun and Berserkjahraun Eruptions|journal =Journal of Petrology|volume =62|issue =9|year =2021|doi =10.1093/petrology/egab054}}</ref> and the older alkaline basalts were alkali [[olivine]]  and more recent [[mugearite]] in composition.<ref name=EIVVES>{{cite web|url =https://icelandicvolcanoes.is/?volcano=VES|title =Catalogue of Icelandic Volcanoes - Vestmannaeyjar |access-date =3 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Höskuldsson |first1 =Ármann}}{{rp|loc=Detailed Description}}</ref> The basalts of the southern EVZ on land are rarely silicic but the volcanoes can have explosive phreatomagmatic eruptions.<ref>{{cite web|url =https://icelandicvolcanoes.is/?volcano=KAT|title =Catalogue of Icelandic Volcanoes - Katla |access-date =4 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Larsen |first1 =Guðrún|last2=Guðmundsson|first2=Magnús T.}}{{rp|loc=Detailed Description}}</ref>

Overall the surface area of post glacial erupted rocks of Iceland is 92% basalt, 4% [[basaltic andesite]]s, 1% [[andesite]]s, and 3% dacite-rhyolites.<ref name=Sigmundsson2020>{{cite journal|last1 =Sigmundsson|first1 =F.|last2 =Einarsson|first2 =P.|last3 =Hjartardóttir|first3 =Á.R.|last4 =Drouin|first4 =V.|last5 =Jónsdóttir|first5 =K.|last6 =Arnadottir|first6 =T.|last7 =Geirsson|first7 =H.|last8 =Hreinsdottir|first8 =S.|last9 =Li|first9 =S.|last10 =Ofeigsson|first10 =B.G.|year =2020|title =Geodynamics of Iceland and the signatures of plate spreading|journal =Journal of Volcanology and Geothermal Research|volume =391|page=106436|doi =10.1016/j.jvolgeores.2018.08.014|bibcode =2020JVGR..39106436S}}</ref>

==Important eruptions==
''See also : [[List of volcanic eruptions in Iceland]]''

===Largest Holocene eruptions ===
Due to incomplete surveys, which also need to be confined to [[subaerial eruption]]s and not include [[igneous intrusion]]s, the accumulative amounts of [[dense-rock equivalent]] erupted in Iceland will be underestimated.<ref name=Thordarson2008/> The amounts known are some of the most significant contributions to recent eruptive volumes on Earth.<ref name=Thordarson2008/>  Since the last ice age 91% of the magma erupted in Iceland has been [[mafic]], 6% intermediate in composition and 3% [[silicic]].<ref name=Thordarson2008/>{{rp|203}} The number of eruptions estimated in this 11,700 odd year period can only be an approxiamate figure,{{efn|Number of eruptions is a ballpark figure.<ref name=Thordarson2008/>{{rp|202}} See note on inadequacy DRE tephra Icelandic record for some reasons. Even today eruptions under a glacier might be suspected but not proved.|name=NE}} but about three to four explosive ones occur for every purely effusive one.<ref name=Thordarson2008/>{{rp|203}}
{| class="wikitable sortable"
|+ Accumulative Holocene eruptions by zone or belt<ref name=Thordarson2008/>{{rp|203}} <!---add in eruptive volumes from 2023 once accurate volumes in literature , not intended to show for individual volcanoes or volcanic system but for example helka may have a total volume of about 42 km3 in period...not mentioned as I have not been able to find an acaedmic or level 2 source rather than a blog--->
|-
! Volcanic Zone or Belt !! Lava [[Dense-rock equivalent|DRE]]{{efn|DRE for lava flows is known to be 50% inaccurate if based on the planimetric method rather than preeruption and posteruption digital elevation models.<ref>{{cite journal|last1 =Pedersen|first1 =G.B.M.|last2 =Belart|first2 =J.M.C.|last3 =Magnússon|first3 =E.|last4 =Vilmundardóttir|first4 =O.K.|last5 =Kizel|first5 =F.|last6 =Sigurmundsson|first6 =F.S.|last7 =Gísladóttir|first7 =G.|last8 =Benediktsson|first8 =J.A.|year=2018|title =Hekla volcano, Iceland, in the 20th century: Lava volumes, production rates, and effusion rates|journal =Geophysical Research Letters|volume =45|issue =4|pages =1805–1813|doi =10.1002/2017GL076887|bibcode =2018GeoRL..45.1805P|hdl =20.500.11815/967|hdl-access =free}}</ref>|name=LDRE}} !! Tephra DRE{{efn|Inaccuracies in tephra DRE estimates are worse than for lava as: less than 35% of Holocene explosive eruptions have been associated with their tephra layer, Iceland's post-glacial tephra stratigraphy is incomplete and distribution of less than 10% of the known tephra layers have been mapped.<ref name=Thordarson2008/>{{rp|203}}|name=TDRE}} !! Total DRE{{efn|name=LDRE}}{{efn|name=TDRE}} !! Number eruptions{{efn|name=NE}} !!Comment
|-
| [[Geological deformation of Iceland#Eastern volcanic zone|Eastern volcanic zone]] || {{cvt|{{ #expr: 337-163.4 +0.025+1.6}}|km3|1|adj=ri1}} || {{cvt|{{ #expr: 163.4+0.11+0.8 }}|km3|1|adj=ri1}} || {{cvt|{{ #expr: 337+0.025+0.8+1.6 }}|km3|1|adj=ri1}} || {{ #expr: 2023+3}} ||<ref>{{cite gvp|title=Eyjafjallajökull|vn=372020|access-date=2024-02-18}}{{rp|loc=Most Recent Bulletin Report: April 2011 (BGVN 36:04)}}</ref><ref>{{cite web|url =https://icelandicvolcanoes.is/?volcano=GRV|title =Catalogue of Icelandic Volcanoes: Grímsvötn|access-date =18 February 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Guðmundsson|first2 =G|last2 =Larsen|first1=M.T.}}{{rp|loc=Short Description}}</ref><ref>{{cite web|url =https://icelandicvolcanoes.is/?volcano=BAR|title =Catalogue of Icelandic Volcanoes:Bárðarbunga|access-date =28 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Larsen |first1 =G. |first2 =M.T. |last2 =Guðmundsson}}{{rp|loc=Short Description}}</ref> Includes individual eruptions from [[Laki]] {{cvt|15.1|km3|1|adj=ri1}}, [[Eldgjá]] {{cvt|19.6|km3|1|adj=ri1}} and [[Þjórsá Lava]] {{cvt|25|km3|1|adj=ri1}}.<ref name=Thordarson2008/>  
|-
| [[Geological deformation of Iceland#Western volcanic zone|Western volcanic zone]]  || {{cvt|{{ #expr: 94+0.01 }}|km3|1|adj=ri1}} || {{cvt|0.01|km3|1|adj=ri1}} || {{cvt|94|km3|1|adj=ri1}} || {{ #expr: 47}} || 
|-
| [[Geological deformation of Iceland#Northern volcanic zone|Northern volcanic zone]] || {{cvt|{{ #expr: 94-3.3 }}|km3|1|adj=ri1}} || {{cvt|3.3|km3|1|adj=ri1}} || {{cvt|94|km3|1|adj=ri1}} ||  {{ #expr: 146}} ||
|-
| [[Reykjanes volcanic belt]] || {{cvt|{{ #expr: 29-7+0.16 +0.1}}<!--0.1 figure from Jul 23 to Feb 24 see https://en.vedur.is/about-imo/news/--->|km3|1|adj=ri1}} || {{cvt|{{ #expr: 29-7+0.001 }}<!--0.001 figure from Feb 2024 see https://en.vedur.is/about-imo/news/--->|km3|1|adj=ri1}} || {{cvt|{{ #expr: 29+0.16+.0.1+0.001}}<!--0.1 figure from Jul 23 to Feb 24, 0.001 figure from Feb 2024 see https://en.vedur.is/about-imo/news/--->|km3|1|adj=ri1}} || {{ #expr: 144+7}} ||<ref>{{cite web|url =https://icelandicvolcanoes.is/?volcano=KRY|title =Catalogue of Icelandic Volcanoes:Krýsuvík|access-date =28 January 2024| publisher =Icelandic Meteorological Office, Institute of Earth Sciences at the University of Iceland, Civil Protection Department of the National Commissioner of the Iceland Police|year=2019|last1 =Einarsson|first1 =S.}}{{rp|loc=Detailed Description}}</ref> <!-- add in post 2022 DREs as become available : as of 18 Feb 2024 represented by values 0.1 and 0.001 from IMO bulletins 2023 to 2024 see https://en.vedur.is/about-imo/news/---> Ongoing as of 2025 
|-
| [[Geological deformation of Iceland#Snæfellsnes volcanic belt|Snæfellsnes volcanic belt]] || {{cvt|{{ #expr: 9-1.3 }}|km3|1}} || {{cvt|1.3|km3|1|adj=ri1}} || {{cvt|9|km3|1|adj=ri1}} || {{ #expr: 57}} ||
|-
| [[Geological deformation of Iceland#Öræfi volcanic belt|Öræfajökull volcanic belt]] || {{cvt|{{ #expr:3-2.4  }}|km3|1|adj=ri1}} || {{cvt|2.4|km3|1|adj=ri1}} || {{cvt|3|km3|1|adj=ri1}} || {{ #expr: 8}} || 
|-
| [[Geological deformation of Iceland#Mid-Iceland belt|Mid-Iceland belt]] || {{cvt|{{ #expr: 1-0  }}|km3|1|adj=ri1}} || {{cvt|0|km3|1|adj=ri1}} || {{cvt|1|km3|1|adj=ri1}} || {{ #expr: 9}} || 
|}
[[File:Eyjafjallajökull ash cloud 20100417.jpg|thumb|220px|Eruption column of [[Eyjafjallajökull]] in 2010]]
[[File:Bárðarbunga Volcano, September 4 2014 - 15123275226.jpg|thumb|220px|Eruptions at [[Holuhraun]] (Bárðarbunga-Veiðivötn volcanic system), 2014]]
[[Image:Grábrókkrater.jpg|thumb|220px|The craters of [[Grábrók]]]]
[[File:Geldingadalagos.jpg|thumb|220px|2021 [[Fagradalsfjall]] volcanic eruption]]
[[File:Litli-Hrútur eruption 2023.jpg|thumb|220px|Litli-Hrútur eruption 2023]]
[[File:Iceland Volcano Eruption 19 December 2023.jpg|thumb|220px|Sundhnúkur in Iceland on December 19th 2023.]]

===Hekla===
[[Hekla]] has erupted more than 20 times in recorded history.  It was known to medieval Europeans as the Gate of Hell; that reputation persisted into the 19th century.<ref>{{cite journal | author = Sigurdur Þórarinsson | author-link = Sigurdur Thorarinsson
  | title = The eruption of Hekla in historical times. Vol. I: The eruption of Hekla 1947–48
  | year = 1967 | journal = Soc. Sci. Islandica| volume = 38 | pages = 1–183 }}</ref>

===Laki/Skaftáreldar 1783–1784===
The most deadly volcanic eruption of Iceland's history was the so-called [[Laki|Skaftáreldar]] (fires of [[Skaftá]]) in 1783–1784.<ref name=Thordarson2003>{{cite journal|last1=Thordarson|first1=T.|last2=Self|first2=S.|year=2003|title=Atmospheric and environmental effects of the 1783–1784 Laki eruption: A review and reassessment |journal=Journal of Geophysical Research: Atmospheres|volume=108|issue=D1|doi=10.1029/2001JD002042|doi-access=free|page=4011 |bibcode=2003JGRD..108.4011T |hdl=20.500.11820/17d8aae9-d2bf-4120-b61a-31c6966a7e24|hdl-access=free}}{{rp|loc=4. Volcanic Pollution From Laki and Its Effects on the Environment}}</ref> The eruption was in the [[volcanic crater|crater]] row ''Lakagígar'' (craters of Laki) southwest of [[Vatnajökull]] glacier. The craters are a part of a larger volcanic system with the subglacial [[Grímsvötn]] as a central volcano. Roughly a fifth of the Icelandic population died because of the eruption.<ref name=Thordarson2003 /> Most died not because of the lava flow or other direct effects of the eruption but from indirect effects, including changes in climate and illnesses in livestock in the following years caused by the ash and poisonous gases from the eruption.<ref name=Thordarson2003 /> The eruption resulted in the second largest basaltic lava flow from a single eruption in
historic times.<ref name=Thordarson2003E>{{cite journal|last1=Thordarson|first1=T.|last2=Self|first2=S.|year= 2003|title=Atmospheric and environmental effects of the 1783–1784 Laki eruption: A review and reassessment|journal=Journal of Geophysical Research: Atmospheres|volume=108|issue=D1|doi=10.1029/2001JD002042|doi-access=free|page=4011 |bibcode=2003JGRD..108.4011T|hdl=20.500.11820/17d8aae9-d2bf-4120-b61a-31c6966a7e24|hdl-access=free}}{{rp|loc=2.2. Eruption History}}</ref>

===Eldfell 1973===
[[Eldfell]] is a volcanic cone on the  east side of the island of [[Heimaey]] which formed during an eruption in January 1973.<ref>{{Cite web|url=https://guidetoiceland.is/nature-info/the-most-infamous-eruptions-in-icelandic-history#heimaey-vestmannaeyjar-1973-aa-a-a|title=The Most Infamous Eruptions in Icelandic History|website=guidetoiceland.is|access-date=2021-04-04}}</ref> The eruption happened without warning, causing the island's population of about 5,300 people to evacuate on fishing boats within a few hours. Importantly, the progress of lava into the harbour was slowed by manual spraying of seawater. One person died, and the eruption resulted in the destruction of homes and property on the island.<ref>{{cite web|url=https://pubs.usgs.gov/gip/heimaey/heimaey.pdf |title=Man Against Volcano: The Eruption on Heimaey, Vestmannaeyjar, Iceland (2nd Edition) |access-date=2023-01-13 |last=Williams |first=Richard S. Jr. |author2=James G. Moore |year=1983 |publisher=[[USGS]] }}</ref>{{rp|11}}

===Eyjafjallajökull 2010===
{{Main|2010 eruptions of Eyjafjallajökull}}
The eruption under [[Eyjafjallajökull]] in April 2010 caused extreme disruption to air travel across western and northern Europe over a period of six days in April 2010. About 20 countries closed their airspace to commercial jet traffic and it affected approximately 10 million travellers.<ref>{{cite news|title=''Volcanic eruptions: Science and Risk Management''|date=27 May 2011|first=Bente Lilja|last=Bye|work=Science 2.0|url=http://www.science20.com/planetbye/volcanic_eruptions_science_and_risk_management-79456|access-date=28 May 2011}}</ref>

The eruption had a [[Volcanic explosivity index|VEI]] of 4, the largest known from Eyjafjallajökull.<ref>[https://volcano.si.edu/volcano.cfm?vn=372020 Eyjafjallajökull. Eruptive History. Global Volcanism Program.] Accessed 19 August 2020.</ref> Several previous eruptions of Eyjafjallajökull have been followed soon afterwards by eruptions of the larger volcano [[Katla volcano|Katla]], but after the 2010 eruption, no activity occurred at Katla.<ref name="CIV1">[http://icelandicvolcanoes.is/# ''Katla. Detailed description.'' In: Catalogue of Icelandic Volcanoes.] {{Webarchive|url=https://web.archive.org/web/20210417114625/http://icelandicvolcanoes.is/ |date=2021-04-17 }} Accessed 19 August 2020</ref>

===Grímsvötn 2011===
{{Main|2011 eruption of Grímsvötn}}
The eruption in May 2011 at [[Grímsvötn]] under the [[Vatnajökull]] glacier sent thousands of tonnes of ash into the sky in a few days, raising concerns of the potential for travel chaos across northern Europe although only about 900 flights were initially disrupted.<ref>{{cite web|url=http://www.flightglobal.com/articles/2011/05/26/357246/european-proceedures-cope-with-new-ash-cloud.html|title=European proceedures (sic) cope with new ash cloud|date=26 May 2011|work=Flightglobal|author=David Learmount|archive-url=https://web.archive.org/web/20150703022217/http://www.flightglobal.com/news/articles/european-proceedures-cope-with-new-ash-cloud-357246/|archive-date=July 3, 2015|access-date=September 28, 2015}}</ref>

===Holuhraun 2014–2015===
{{Main|2014–2015 eruption of Bárðarbunga}}
Bárðarbunga is a [[stratovolcano]] and is roughly {{convert|2000|m}} above sea level in central Iceland, i.e. in the northern edge of Vatnajökull.<ref>{{Cite web|url=https://www.volcanodiscovery.com/bardarbunga.html|title=Bardarbunga|website=www.volcanodiscovery.com|access-date=2017-10-06}}</ref> This makes it the second highest mountain in Iceland.

Holuhraun is an older lavafield situated {{convert|50|km|abbr=on}} north-east of Bárðarbunga, {{convert|20|km|abbr=on}} south of [[Askja]] (last eruption 1961), at an altitude of about {{convert|700|m|abbr=on}}. Here the eruption started on August 17, 2014, and lasted for 180 days.<ref name=Gudmundsson2016>{{Cite journal|last1=Gudmundsson|first1=Magnús T.|last2=Jónsdóttir|first2=Kristín|last3=Hooper|first3=Andrew|last4=Holohan|first4=Eoghan P.|last5=Halldórsson|first5=Sæmundur A.|last6=Ófeigsson|first6=Benedikt G.|last7=Cesca|first7=Simone|last8=Vogfjörd|first8=Kristín S.|last9=Sigmundsson|first9=Freysteinn|date=2016-07-15|title=Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow|journal=Science|language=en|volume=353|issue=6296|article-number=aaf8988|doi=10.1126/science.aaf8988|issn=0036-8075|pmid=27418515|hdl=10447/227125 |s2cid=206650214|url=http://eprints.whiterose.ac.uk/103058/1/Gudmundsson_et_al_2016_Science.pdf}}</ref> The 2014–2015 eruption was Iceland's largest in 230 years.<ref>{{Cite journal|last1=Hudson|first1=T. S.|last2=White|first2=R. S.|last3=Greenfield|first3=T.|last4=Ágústsdóttir|first4=T.|last5=Brisbourne|first5=A.|last6=Green|first6=R. G.|date=2017-09-16|title=Deep crustal melt plumbing of Bárðarbunga volcano, Iceland|journal=Geophysical Research Letters|language=en|volume=44|issue=17|article-number=2017GL074749|doi=10.1002/2017gl074749|bibcode=2017GeoRL..44.8785H|s2cid=134072252|issn=1944-8007|url=http://eprints.esc.cam.ac.uk/4000/1/Hudson_et_al-2017-Geophysical_Research_Letters.pdf|archive-date=2021-07-25|access-date=2019-09-24|archive-url=https://web.archive.org/web/20210725065649/http://eprints.esc.cam.ac.uk/4000/1/Hudson_et_al-2017-Geophysical_Research_Letters.pdf}}</ref> Following a major earthquake swarm, multiple lava fountain eruptions began in [[Holuhraun]].<ref name="Ljós norðan jökuls Töldu annað gos hafið">{{cite web|title=Ljós norðan jökuls: Töldu annað gos hafið|url=http://www.ruv.is/frett/ljos-nordan-jokuls-toldu-annad-gos-hafid|website=www.ruv.is/|date=31 August 2014 |publisher=RÚV|access-date=24 September 2014|ref=RUV}}</ref> The lava flow rate was between {{convert|250|and|350|m3/s|abbr=on}} and came from a [[Dyke (geology)|dyke]] over {{convert|40|km|abbr=on}} long.<ref>See e.g. http://earthice.hi.is/bardarbunga_2014 {{Webarchive|url=https://web.archive.org/web/20210415105100/http://earthice.hi.is/bardarbunga_2014 |date=2021-04-15 }}  Institute of Earth Sciences, University of Iceland:Bardarbunga 2014</ref><ref>See also Icelandic media RÚV: http://www.ruv.is/frett/seismic-activity-still-strong  Received Sept. 24, 2014</ref> An ice-filled [[subsidence]] bowl over {{convert|100|km2|abbr=on}} in area and up to {{convert|65|m|abbr=on}} deep formed as well.<ref name=Gudmundsson2016 /> There was very limited ash output from this eruption. The primary concern with this eruption was the large plumes of [[sulphur dioxide]] (SO<sub>2</sub>) in the atmosphere which adversely affected breathing conditions across Iceland, depending on wind direction. The volcanic cloud was also transported toward Western Europe in September 2014.<ref>{{Cite journal|last1=Boichu|first1=M.|last2=Chiapello|first2=I.|last3=Brogniez|first3=C.|last4=Péré|first4=J.-C.|last5=Thieuleux|first5=F.|last6=Torres|first6=B.|last7=Blarel|first7=L.|last8=Mortier|first8=A.|last9=Podvin|first9=T.|date=2016-08-31|title=Current challenges in modelling far-range air pollution induced by the 2014–2015 Bárðarbunga fissure eruption (Iceland)|journal=Atmos. Chem. Phys.|volume=16|issue=17|pages=10831–10845|doi=10.5194/acp-16-10831-2016|bibcode=2016ACP....1610831B|issn=1680-7324|doi-access=free|hdl=2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/240003|hdl-access=free}}</ref>

===Fagradalsfjall 2021–2022===
{{Main|Fagradalsfjall}}
Following a three-week period of increased seismic activity, an eruption fissure developed near [[Fagradalsfjall]],<ref>{{Cite journal |last1=Bindeman |first1=I. N. |last2=Deegan |first2=F. M. |last3=Troll |first3=V. R. |last4=Thordarson |first4=T. |last5=Höskuldsson |first5=Á |last6=Moreland |first6=W. M. |last7=Zorn |first7=E. U. |last8=Shevchenko |first8=A. V. |last9=Walter |first9=T. R. |date=2022-06-29 |title=Diverse mantle components with invariant oxygen isotopes in the 2021 Fagradalsfjall eruption, Iceland |journal=Nature Communications |language=en |volume=13 |issue=1 |page=3737 |doi=10.1038/s41467-022-31348-7 |pmid=35768436 |pmc=9243117 |bibcode=2022NatCo..13.3737B |issn=2041-1723}}</ref> a mountain on the [[Reykjanes Peninsula]].  Lava flow from a 200-meter fissure was first discovered by an [[Icelandic Coast Guard]] helicopter on March 19, 2021, in the [[Fagradalsfjall#Eruption fissures in Geldingadalir|Geldingadalur]] area near [[Grindavík]], and within hours the fissure had grown to {{convert|500|m|abbr=on}} in length.<ref>Icelandic Media RÚV:  https://www.ruv.is/frett/2021/03/19/eldgos-hafid-vid-fagradalsfjall. Retrieved 19 March 2021.</ref>

Another eruption, very similar to the 2021 eruption, began on 3 August 2022,<ref>{{Cite web |date=2022-08-03 |title=Volcano near Iceland's main airport erupts again after series of earthquakes – CBS News |url=https://www.cbsnews.com/news/fagradalsfjall-volcano-eruption-iceland/ |access-date=2023-12-19 |publisher=CBS News |language=en-US}}</ref> and ceased on 21 August 2022.
[[File:The blue Lagoon, Iceland (5454149170).jpg|thumb|220px|[[ʻAʻā]] (''apalhraun'') field near [[Blue Lagoon (geothermal spa)|Blue Lagoon]]]] <!--- repositioned picture here as this very near location of Sundhnúkur eruption so sort of overlaps--->

===Litli-Hrútur 2023===
On 10 July 2023 at 16:40 UTC, a fissure eruption began adjacent to the summit of [[Litli-Hrútur]].<ref>{{cite web | title=Latest news on the volcanic eruption on the Reykjanes Peninula {{sic|nolink=y}}| website=Icelandic Meteorological office | date=2023-07-10 | url=https://en.vedur.is/about-imo/news/earthquake-activity-in-fagradalsfjall-area | access-date=2023-07-13|archive-url=https://web.archive.org/web/20230710212746/https://en.vedur.is/about-imo/news/earthquake-activity-in-fagradalsfjall-area|archive-date=10 July 2023}}</ref>

===Sundhnúkur 2023–2025===
{{Main|2023–2025 Sundhnúkur eruptions}}
On December 18, 2023, at 22:17 near Hagafell, the volcano began a fissure eruption.<ref>{{cite web |title=Continued likelihood of an eruption at the Sundhnúksgígar crater row |publisher=Icelandic Meteorological office |date=2024-01-12 |url=https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night |access-date=2023-07-13}}</ref> In January, 2024 lava from this eruption destroyed 3 houses in the nearby town of [[Grindavík]].<ref>{{Cite web |date=2024-01-15 |title=Iceland volcano:Three Grindavik homes burn but lava defences save rest of town |url=https://www.independent.co.uk/news/world/europe/iceland-volcano-eruption-today-grindavik-news-live-b2478602.html |access-date=2024-01-15 |website=The Independent |language=en}}</ref>

==Structure of lava fields==
[[File:2014-04-28 13-14-48 Iceland Norðurland Eystra - Reykjahlíð.JPG|thumb|left|[[Pāhoehoe]] (''helluhraun'') [[lava field]]s in Iceland]]
The smooth flowing basaltic lava [[Lava#P.C4.81hoehoe|pāhoehoe]] is known in Icelandic as ''helluhraun'' {{IPA|is|ˈhɛtlʏˌr̥œyːn|}}.<ref name=Islandsbok-Liden group=Islandsbok>{{cite book|last1=Lidén|first1=Eva|title=Kall ökensand och varma källor. En bok om Island|date=1994|publisher=Föreningen Natur och Samhälle i Norden|location=Båstad|isbn=978-91-85586-07-3|pages=8–9|language=sv|chapter=Geologi-så bildades Island}}</ref> It forms smooth surfaces that are quite easy to cross. More viscous lava forms [[Lava#.CA.BBA.CA.BB.C4.81|ʻaʻā]] flows, known in Icelandic as ''apalhraun'' {{IPA|is|ˈaːpalˌr̥œyːn|}}.<ref name=Islandsbok-Liden group=Islandsbok/> The loose, broken, sharp, spiny surface of an ʻaʻā flow makes [[hiking]] across it difficult, slow and dangerous, it is easy to stick a foot into a hole and break a leg.
{{clear}}

==See also==
* [[Geography of Iceland]]
* [[Geology of Iceland]]
* [[Geological deformation of Iceland]]
* [[List of volcanoes in Iceland]]
* [[List of volcanic eruptions in Iceland]]
* [[Geothermal power in Iceland]]
* [[Geology of Reykjanes Peninsula]]
* [[Surtsey]]

==Notes==
{{notelist}}

==References==
{{reflist}}

===Non-English references===
{{reflist|group=Islandsbok}}

==External links==
*Photos of the [https://web.archive.org/web/20051101231029/http://www.millhouse.nl/grimsvotn2004.html Grímsvötn (2004)] and [https://web.archive.org/web/20100418185156/http://www.millhouse.nl/eyjafjallajokull/ Eyjafjallajökull (2010)] eruptions (Fred Kamphues)
*Map: [http://www.geocodezip.com/v2_activeVolcanos.asp active volcanoes of the world]

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*Volcano Discovery: [https://www.volcanodiscovery.com/iceland.html Iceland]
* [https://en.vedur.is/earthquakes-and-volcanism/articles/nr/1874 List of volcanic eruptions in Iceland since 1900], [[Icelandic Met Office]]

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{{DEFAULTSORT:Volcanism Of Iceland}}
[[Category:Volcanism of Iceland| ]]
[[Category:Volcanic systems of Iceland| ]]