View source for Irazú Volcano

{{Short description|Active volcano in Costa Rica}}
{{Use dmy dates|date=July 2023}} 
{{Redirect|Irazu}}
{{more citations needed|date=February 2010}}
{{Infobox mountain
| name = Irazú Volcano
| photo = Irazu Volcano.JPG
| photo_caption = Irazú Crater
| elevation_m = 3432
| elevation_ref = <ref name=gvp>{{cite gvp|vn=345060|name=Irazú|access-date=2010-03-11}}</ref>
| prominence = 
| prominence_ref = 
| map = Costa Rica |relief=1
| label_position = right
| location = [[Costa Rica]]
| range = [[Cordillera Central, Costa Rica|Cordillera Central]]
| coordinates = {{coord|9|58|45|N|83|51|09|W|type:mountain_region:CR_scale:100000|format=dms|display=inline,title}}
| range_coordinates = 
| coordinates_ref = <ref name=gvp/>
| topo = 
| type = [[Complex volcano|Complex]] [[Stratovolcano]]
| age = 
| volcanic_arc = [[Central America Volcanic Arc]]
| last_eruption = December 1994<ref name=gvp/>
| first_ascent = 
| easiest_route = 
}}

The '''Irazú Volcano''' ({{langx|es|Volcán Irazú}}) is an active [[volcano]] in [[Costa Rica]], situated in the [[Cordillera Central, Costa Rica|Cordillera Central]] close to the city of [[Cartago, Costa Rica|Cartago]].

The name might have come from either the combination of "ara" (point) and "tzu" (thunder){{clarify|date=December 2013|reason=What language are these words?}} or a corruption of ''Iztarú'', which was the name of an indigenous village on the flanks of the volcano. In Costa Rica it is known by the name of "El Coloso" (the Colossus) due to the catastrophes that it has unleashed in the past.

The volcano's summit has several craters, one of which contains Diego de la Haya, a green [[Volcanic crater lake|crater lake]] of variable depth. At 11,260 feet (3,432 m), the Irazú Volcano is the highest active volcano in Costa Rica.<ref>{{cite web|last=Stater|first=Adam|title=Elevation of Irazu Volcano|url=http://www.anywherecostarica.com/attractions/national-park/irazu-volcano|website=Anywherecostarica.com|access-date=23 September 2017}}</ref>  It is thus a popular [[tourism|tourist]] spot. It is easily visited from [[San José, Costa Rica|San José]], the Costa Rican capital, with a road leading right up to the summit craters and a weekly bus service to the top.  The summit of the volcano also houses a few television transmitters for television stations in San José.

From the top it is possible to see both the Atlantic and Pacific oceans  on a clear day.<ref name=GSA>{{cite web|url=http://www.rci.rutgers.edu/~carr/Alv%20Irazu.pdf|author=Guillermo E. Alvarado, el. al.|date=2006|title=''Recent volcanic history of Irazú volcano, Costa Rica: Alternation and mixing of two magma batches, and pervasive mixing''|publisher=[[Geological Society of America]]|quotation=Special Paper 412|website=Rci.rutgers.edu|access-date=23 September 2017|url-status=dead|archive-url=https://web.archive.org/web/20101206132105/http://www.rci.rutgers.edu/~carr/Alv%20Irazu.pdf|archive-date=6 December 2010}}</ref> However, such clear days are rare, and the volcano's summit is usually cloud-covered.

The volcano is contained within the Irazú Volcano National Park, which spreads across 5,705 acres (2,300 ha). The national park contains both primary and secondary montane forests and is home to armadillos, owls, rabbits, foxes, woodpeckers, and hummingbirds.<ref>{{cite web|last=Stater|first=Adam|title=Irazu Volcano National Park|url=http://www.anywherecostarica.com/attractions/national-park/irazu-volcano|website=Anywherecostarica.com|access-date=23 September 2017}}</ref>

== Geology ==
The Irazú volcano is a [[Complex volcano|complex]] volcanic shield. It is the highest active volcano in Costa Rica, and has an area of {{convert|500|sqkm|sqmi|abbr=on}}. It has an irregular subconic shape, and temperatures at its summit vary between {{convert|3|and|17|C|F}}, with a record low of −3&nbsp;°C(26.6&nbsp;°F) <ref>{{Cite web|url=http://www.garcimunoz.com/irazu.html|title=403 Forbidden|access-date=18 January 2020|archive-date=11 August 2022|archive-url=https://web.archive.org/web/20220811085725/http://www.garcimunoz.com/irazu.html|url-status=dead}}</ref> and a record high of 23.2&nbsp;°C(73.4&nbsp;°F).<ref>{{cite web|url=https://www.imn.ac.cr/documents/10179/14631/FEBRERO|title=Información climática|website=imn.ac.cr
|language=es|page=10|access-date=7 July 2023}}</ref> Irazu volcano is a [[stratovolcano]] with a summit elevation of {{convert|3432|m|ft|sigfig=4}}. Its five craters are easily differentiated.<ref name=gvp/> The most important ones, because of their activity, are The Main Crater and the Diego de la Haya crater. The Main Crater is almost circular, has very inclined walls and it measures {{convert|1050|m|ft|sigfig=3}} in diameter and {{convert|300|m|ft|sigfig=2}} deep. The Diego de la Haya crater is {{convert|600|m|ft|sigfig=2}} in diameter and {{convert|100|m|ft|sigfig=2}} deep. Other craters are Playa Hermosa, La Laguna, and El Piroclastico.<ref>{{Cite web |last=McArthur |first=Sarah |date=2023-11-02 |title=Irazú Volcano National Park in Costa Rica: Guide to Visiting |url=https://www.costaricavibes.com/guide-to-irazu-volcano/ |access-date=2023-11-02 |language=en-US}}</ref>

Irazú is the southernmost of the ten [[Quaternary]] volcanoes which form a northwest-trending line through central and northern Costa Rica.<ref name=GSA/> [[Radioactive dating]] has shown an age of at least 854,000 years with eruption peaks at 570,000 years and the most recent active phase from 136,000 years to present. The most recent activity includes lava flows along with [[strombolian]] and [[phreatomagmatic]] explosions.<ref name=GSA/> Lava types include [[basalt]] and [[andesite]] erupted during different events suggesting the volcano is fed by two distinct [[magma chamber]]s.<ref name=GSA/> Scientists believed that pulses of magma mixed together in the chamber before climbing upward—a process estimated to take several thousands of years. But Columbia University volcanologists found that the eruption of Costa Rica's Irazu volcano in 1963 was likely triggered by magma that took a nonstop route from the mantle over just a few months.  Study authors called it the highway from hell.<ref>Ruprecht P, Plank T. Feeding andesitic eruptions with a high-speed connection from the mantle. Nature. 2013;500(7460):68–72.</ref>

{{Panorama
| image      = File:Irazu-pano.jpg
| fullwidth  = 1920
| fullheight = 354
| caption    = {{center|A [[panorama|panoramic]] view of the Irazú Volcano }}
| alt        = Panoramic view of Irazú Volcano
| height     = 177
}}
{{Panorama
| image      = File:DirkvdM irazu 2.jpg
| fullwidth  = 1920
| fullheight = 354
| caption    = {{center|Panorama of Irazú Volcano. }}
| alt        = Panorama of Irazú Volcano
| height     = 177
}}
{{Panorama
| image      = File:Irazú Volcano 01.jpg
| fullwidth  = 1920
| fullheight = 354
| caption    = {{center|View of the crater with the dry lake. }}
| alt        = View of the crater with the dry lake
| height     = 177
}}

==Eruptive history==
{{Main|1963 eruption of Irazú Volcano}}
[[File:Irazu4-10MGLeonard1963.jpg|thumb|Remote view of the 1963 eruption]]
Irazú has erupted frequently in historical times — at least 23&nbsp;times since its first historically recorded <ref name=gvp-eruptions>{{cite gvp|vn=345060|vtab=Eruptions|title=Irazú: Eruptive History}}</ref> eruption in 1723.  Its most famous eruption began in mid-March 1963, a few days before US President [[John F. Kennedy]] started a [[state visit]] to Costa Rica.<ref>{{Cite news|title=Central America Talks Ready to Open Monday|last=Natanson|first=George|date=15 May 1963|work=Los Angeles Times|page=22}}</ref> It showered the capital [[San José, Costa Rica|San José]] and much of the central highlands of Costa Rica with [[Volcanic ash|ash]].<ref>{{Cite news|url=https://news.google.com/newspapers?nid=1946&dat=19780318&id=8FsxAAAAIBAJ&pg=872,562775|title=Mountainous Costa Rica is a Caribbean Switzerland|last=Scholes|first=Frank|date=18 Mar 1978|work=Montreal Gazette|access-date=10 Jul 2018|page=17}}</ref> Eruptions continued for two years.<ref>{{Cite news|url=http://www.ticotimes.net/travel/irazu-volcano|title=Among Costa Rican volcanoes, Irazú is king of the hill|work=The Tico Times Costa Rica|access-date=2018-07-10|language=en-US}}</ref>

Its historical eruptions generally have [[Volcanic explosivity index|VEIs]] of 1 to 3. All historical eruptions have been [[explosive eruptions|explosive]], and there have been many [[phreatic eruption]]s, and some have produced [[pyroclastic flow]]s. The latest eruption lasted only 1 day, and occurred on December 8, 1994. It occurred at a flank vent and was a phreatic eruption, which produced [[lahar]]s.<ref name=gvp-eruptions />

==Climate==
{{Weather box|width=auto
|location = Volcán Irazú, Costa Rica (2005–2018)
|metric first = y
|single line = y
|Jan high C = 12.6
|Feb high C = 14.2
|Mar high C = 15.8
|Apr high C = 16.4
|May high C = 15.4
|Jun high C = 14.2
|Jul high C = 12.3
|Aug high C = 13.2
|Sep high C = 14.4
|Oct high C = 14.3
|Nov high C = 12.8
|Dec high C = 12.1
|year high C = 
|Jan mean C = 8.3
|Feb mean C = 9.3
|Mar mean C = 10.4
|Apr mean C = 11.1
|May mean C = 10.8
|Jun mean C = 10.2
|Jul mean C = 8.9
|Aug mean C = 9.4
|Sep mean C = 10.1
|Oct mean C = 10.1
|Nov mean C = 9.1
|Dec mean C = 8.3
|year mean C = 
|Jan low C = 4.0
|Feb low C = 4.3
|Mar low C = 4.9
|Apr low C = 5.7
|May low C = 6.2
|Jun low C = 6.2
|Jul low C = 5.5
|Aug low C = 5.6
|Sep low C = 5.8
|Oct low C = 5.8
|Nov low C = 5.4
|Dec low C = 4.4
|year low C = 
|Jan rain mm = 110.4
|Feb rain mm = 57.4
|Mar rain mm = 35.2
|Apr rain mm = 54.1
|May rain mm = 181.2
|Jun rain mm = 166.4
|Jul rain mm = 177.3
|Aug rain mm = 139.9
|Sep rain mm = 201.7
|Oct rain mm = 268.0
|Nov rain mm = 300.1
|Dec rain mm = 173.0
|rain colour = green
|year rain mm = 
|unit rain days =
|Jan rain days = 17
|Feb rain days = 12
|Mar rain days = 12
|Apr rain days = 15
|May rain days = 23
|Jun rain days = 23
|Jul rain days = 24
|Aug rain days = 23
|Sep rain days = 25
|Oct rain days = 28
|Nov rain days = 24
|Dec rain days = 22
|year rain days =
|Jan humidity = 73
|Feb humidity = 64
|Mar humidity = 62
|Apr humidity = 73
|May humidity = 83
|Jun humidity = 89
|Jul humidity = 91
|Aug humidity = 89
|Sep humidity = 89
|Oct humidity = 90
|Nov humidity = 89
|Dec humidity = 81
|source 1 = Instituto Meteorológico Nacional<ref>{{cite web
| url = https://www.imn.ac.cr/mapa
| title = Volcán Irazú - Promedios mensuales
| publisher = Instituto Meteorológico Nacional
| access-date = February 18, 2023
}}</ref>
}}

==Gallery==

<gallery>
File:Sunset from the Summit, Irazu Volcano, Costa Rica - Daniel Vargas.jpg|Sunset from the summit
File:Top View of Diego de la Haya, Irazu Volcano, Costa Rica - Daniel Vargas.jpg|Top view of Diego de la Haya
File:Sunset at Diego de la Haya Crater, Irazu Volcano, Costa Rica - Daniel Vargas.jpg|Sunset at Diego de la Haya crater
File:Crater Irazu volcano CRI 01 2020 1512.jpg|Main crater lagoon
File:Inside_Irazu_Volcano,_Costa_Rica_(Diego_de_la_Haya_Crater)_-_Daniel_Vargas.jpg|Inside Diego de la Haya
File:Extinct Crater, Irazu Volcano, Costa Rica - Daniel Vargas.jpg|Playa Hermosa extinct crater
File:Cráter Playa Hermosa 01.jpg|Playa Hermosa extinct crater
File:Crater Diego de la Haya Irazu volcano CRI 01 2020 3679.jpg|Diego de la Haya crater
File:Diego de la Haya Lagoon, Irazu Volcano, Costa Rica - Daniel Vargas.jpg|Diego de la Haya lagoon
File:Great Walls of the Main Crater, Irazu Volcano, Costa Rica - Daniel Vargas.jpg|Great crater wall
File:DirkvdM irazu 1.jpg|Distant wide view of Irazu volcano
File:The 1918 Irazú Volcano eruption in Costa Rica close to the city of Cartago.png|1918 eruption
File:Irazu3-9MGLeonard1963.jpg|1963 eruption from San José
File:Irazu3-16MGLeonard1963.jpg|1963 eruption

</gallery>

==See also==
{{Portal|Lakes|Volcanoes}}
* [[List of volcanoes in Costa Rica]]
* [[Irazú Volcano National Park]]

==References==
{{Reflist}}

==External links==
{{Commons category|Irazu Volcano}}
* [http://www.ovsicori.una.ac.cr/index.php?option=com_content&view=article&id=27&Itemid=25 Costa Rican Vulcanologic and Seismologic Observatory: Irazú] {{Webarchive|url=https://web.archive.org/web/20160304191443/http://www.ovsicori.una.ac.cr/index.php?option=com_content&view=article&id=27&Itemid=25 |date=2016-03-04 }}
* [https://web.archive.org/web/20050104224543/http://geoimages.berkeley.edu/wwp304/html/RyanGalt.html Virtual Reality Panorama of Volcán Irazú]
* [https://vulcan.wr.usgs.gov/Volcanoes/CostaRica/description_costa_rica_volcanoes.html Costa Rica Volcanoes and Volcanics, USGS]
* [http://www.guiascostarica.com/area55.htm Parque Nacional Volcán Irazú (in Spanish)]

{{Volcanoes of Costa Rica}}
{{Mountains of Costa Rica}}
{{Central American volcanoes}}
{{Authority control}}

{{DEFAULTSORT:Irazu Volcano}}
[[Category:Subduction volcanoes]]
[[Category:Active volcanoes]]
[[Category:Stratovolcanoes of Costa Rica]]
[[Category:Mountains of Costa Rica]]
[[Category:Volcanic crater lakes]]
[[Category:Geography of Cartago Province]]
[[Category:Pleistocene stratovolcanoes]]
[[Category:Holocene stratovolcanoes]]
[[Category:North American 3000 m summits]]