Editing Volcano (section)

==Volcanoes and humans==
[[File:Mauna Loa atmospheric transmission.png|thumb|Solar radiation graph 1958–2008, showing how the radiation is reduced after major volcanic eruptions]]
[[File:SO2 Galapagos 20051101.jpg|thumb|right|[[Sulfur dioxide]] concentration over the [[Sierra Negra (Galápagos)|Sierra Negra Volcano]], [[Galapagos Islands]], during an eruption in October 2005]]
Volcanic eruptions pose a significant threat to human civilization. However, volcanic activity has also provided humans with important resources.

===Hazards===
{{Main|Volcanic hazard}}
There are many different [[types of volcanic eruptions]] and associated activity: [[phreatic eruptions]] (steam-generated eruptions), explosive eruptions of high-[[silica]] lava (e.g., [[rhyolite]]), effusive eruptions of low-silica lava (e.g., [[basalt]]), [[sector collapse]]s, [[pyroclastic flow]]s, [[lahar]]s (debris flows) and [[Volcanic gas|volcanic gas emissions]]. These can pose a hazard to humans. Earthquakes, [[hot spring]]s, [[fumarole]]s, [[mud pot]]s and [[geyser]]s often accompany volcanic activity.

Volcanic gases can reach the stratosphere, where they form [[sulfuric acid]] aerosols that can reflect solar radiation and lower surface temperatures significantly.<ref>{{cite journal|last1=Miles|first1=M.G.|last2=Grainger|first2=R.G.|last3=Highwood|first3=E.J.|title=The significance of volcanic eruption strength and frequency for climate|journal=Quarterly Journal of the Royal Meteorological Society|year=2004|volume=130|issue=602|pages=2361–2376|doi=10.1256/qj.03.60|url=http://eodg.atm.ox.ac.uk/eodg/papers/2004Miles1.pdf|bibcode=2004QJRMS.130.2361M|s2cid=53005926}}

</ref> Sulfur dioxide from the eruption of [[Huaynaputina]] may have caused the [[Russian famine of 1601–1603]].<ref>{{cite web|author=University of California – Davis|title=Volcanic Eruption Of 1600 Caused Global Disruption|date=April 25, 2008|work=ScienceDaily|url=https://www.sciencedaily.com/releases/2008/04/080423135236.htm}}</ref> Chemical reactions of sulfate aerosols in the stratosphere can also damage the [[ozone layer]], and acids such as [[hydrogen chloride]] (HCl) and hydrogen fluoride (HF) can fall to the ground as [[acid rain]]. Excessive fluoride salts from eruptions have poisoned [[livestock]] in Iceland on multiple occasions.<ref>{{cite book|last=Thorarinsson|first=Sigurdur|author-link=Sigurdur Thorarinsson|others=trans. Jóhann Hannesson, Pétur Karlsson|title=Hekla, A Notorious Volcano|year=1970|publisher=Almenna bókafélagið|location=Reykjavík}}</ref>{{rp|pp=39–58}} [[Explosive eruption|Explosive volcanic eruptions]] release the greenhouse gas [[carbon dioxide]] and thus provide a deep source of [[carbon]] for [[biogeochemical cycle]]s.<ref>{{citation-attribution|1={{cite web|url=http://pubs.usgs.gov/of/1997/of97-262/of97-262.html|title=Impacts of Volcanic Gases on Climate, the Environment, and People|first1=Kenneth A.|last1=McGee|first2=Michael P.|last2=Doukas|first3=Richard|last3=Kessler|first4=Terrence M.|last4=Gerlach|date=May 1997|publisher=United States Geological Survey|access-date=August 9, 2014}} }}</ref>

Ash thrown into the air by eruptions can present a hazard to aircraft, especially [[jet aircraft]] where the particles can be melted by the high operating temperature; the melted particles then adhere to the [[turbine]] blades and alter their shape, disrupting the operation of the turbine. This can cause major disruptions to air travel.

[[File:Large eruptions.jpg|thumb|upright=1.3|Comparison of major United States prehistoric eruptions ([[VEI|VEI 7 and 8]]) with major historical volcanic eruptions in the 19th and 20th century (VEI 5, 6 and 7). From left to right: Yellowstone 2.1 Ma, Yellowstone 1.3 Ma, Long Valley 6.26 Ma, Yellowstone 0.64 Ma . 19th century eruptions: Tambora 1815, Krakatoa 1883. 20th century eruptions: Novarupta 1912, St. Helens 1980, Pinatubo 1991.]]

A [[volcanic winter]] is thought to have taken place around 70,000 years ago after the [[supereruption]] of [[Lake Toba]] on Sumatra island in Indonesia.<ref>{{cite web|title=Supervolcano eruption – in Sumatra – deforested India 73,000 years ago|url=https://www.sciencedaily.com/releases/2009/11/091123142739.htm|website=ScienceDaily|date=November 24, 2009}}</ref> This may have created a [[Toba catastrophe theory|population bottleneck]] that affected the genetic inheritance of all humans today.<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/2975862.stm|title=When humans faced extinction|publisher=BBC|date=June 9, 2003|access-date=January 5, 2007}}</ref> Volcanic eruptions may have contributed to major extinction events, such as the [[Ordovician-Silurian extinction events|End-Ordovician]], [[Permian-Triassic]], and [[Late Devonian extinction|Late Devonian]] [[mass extinction]]s.<ref>{{cite web|last1=O'Hanlon|first1=Larry|title=Yellowstone's Super Sister|url=http://www.discovery.com/convergence/supervolcano/others/others_07.html|website=Discovery Channel|archive-url=https://web.archive.org/web/20050314025022/http://dsc.discovery.com/convergence/supervolcano/others/others_07.html|archive-date=March 14, 2005|date=March 14, 2005}}</ref>

The 1815 eruption of [[Mount Tambora]] created global climate anomalies that became known as the "[[Year Without a Summer]]" because of the effect on North American and European weather.<ref>''[https://books.google.com/books?id=ipNcKc0Mv5IC&pg=PA155 Volcanoes in human history: the far-reaching effects of major eruptions]''. Jelle Zeilinga de Boer, Donald Theodore Sanders (2002). [[Princeton University Press]]. p. 155. {{ISBN|0-691-05081-3}}</ref> The freezing winter of 1740–41, which led to widespread [[Irish Famine (1740–1741)|famine]] in northern Europe, may also owe its origins to a volcanic eruption.<ref>{{cite web|last1=Ó Gráda|first1=Cormac|title=Famine: A Short History|url=http://press.princeton.edu/chapters/s8857.html|publisher=Princeton University Press|archive-url=https://web.archive.org/web/20160112061115/http://press.princeton.edu/chapters/s8857.html|archive-date=January 12, 2016|date=February 6, 2009}}</ref>

===Benefits===
{{See also|Volcanogenic massive sulfide ore deposit|Geothermal power}}
Although volcanic eruptions pose considerable hazards to humans, past volcanic activity has created important economic resources. Tuff formed from volcanic ash is a relatively soft rock, and it has been used for construction since ancient times.<ref name="marcari-etal-2007">Marcari, G., G. Fabbrocino, and G. Manfredi. "Shear seismic capacity of tuff masonry panels in heritage constructions." Structural Studies, Repairs and Maintenance of Heritage Architecture X 95 (2007): 73.</ref><ref name="dolan-etal-2019">{{cite journal|last1=Dolan|first1=S.G.|last2=Cates|first2=K.M.|last3=Conrad|first3=C.N.|last4=Copeland|first4=S.R.|title=Home Away from Home: Ancestral Pueblo Fieldhouses in the Northern Rio Grande|journal=Lanl-Ur|date=March 14, 2019|volume=19-21132|pages=96|url=https://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-19-21132|access-date=September 29, 2020}}</ref> The Romans often used tuff, which is abundant in Italy, for construction.<ref name="jackson-etal-2005">{{cite journal|last1=Jackson|first1=M. D.|last2=Marra|first2=F.|last3=Hay|first3=R. L.|last4=Cawood|first4=C.|last5=Winkler|first5=E. M.|title=The Judicious Selection and Preservation of Tuff and Travertine Building Stone in Ancient Rome*|journal=Archaeometry|year=2005|volume=47|issue=3|pages=485–510|doi=10.1111/j.1475-4754.2005.00215.x|doi-access=free|bibcode=2005Archa..47..485J }}</ref> The [[Rapa Nui]] people used tuff to make most of the ''[[moai]]'' statues in [[Easter Island]].<ref name="collins-2016-150-151">Richards, Colin. 2016. [https://books.google.com/books?id=FPQhDAAAQBAJ&dq=moai+construction&pg=PA149 "Making Moai: Reconsidering Concepts of Risk in the Construction of Megalithic Architecture in Rapa Nui (Easter Island)"] {{Webarchive|url=https://web.archive.org/web/20221114150457/https://books.google.com/books?hl=en&lr=&id=FPQhDAAAQBAJ&oi=fnd&pg=PA149&dq=moai+construction&ots=j1xHNuEeze&sig=G8ncDnByQt0qat7itwXSXpSPY4M#v=onepage&q=moai%20construction&f=false |date=November 14, 2022 }}. ''Rapa Nui–Easter Island: Cultural and Historical Perspectives'', pp.150-151</ref>

Volcanic ash and weathered basalt produce some of the most fertile soil in the world, rich in nutrients such as iron, magnesium, potassium, calcium, and phosphorus.<ref name="kiprop-2019">{{cite web|last1=Kiprop|first1=Joseph|date=January 18, 2019|title=Why Is Volcanic Soil Fertile?|url=https://www.worldatlas.com/articles/why-is-volcanic-soil-fertile.html|access-date=November 27, 2020|website=WorldAtlas.com}}</ref> Volcanic activity is responsible for emplacing valuable mineral resources, such as metal ores.<ref name="kiprop-2019" /> It is accompanied by high rates of heat flow from Earth's interior. These can be tapped as [[geothermal power]].<ref name="kiprop-2019" />

Tourism associated with volcanoes is also a worldwide industry.<ref name=Thomaidis2021>{{cite journal|last1=Thomaidis|first1=K|last2=Troll|first2=VR|last3=Deegan|first3=FM|last4=Freda|first4=C|last5=Corsaro|first5=RA|last6=Behncke|first6=B|last7=Rafailidis|first7=S|title=A message from the 'underground forge of the gods': History and current eruptions at Mt Etna|journal=Geology Today|year=2021|volume=37|issue=4|pages=141–9|doi=10.1111/gto.12362|bibcode=2021GeolT..37..141T|s2cid=238802288|url=https://www.earth-prints.org/bitstream/2122/15268/3/Geology_Today_Mt.Etna.pdf}}</ref>

=== Safety considerations ===
Many volcanoes near human settlements are heavily monitored with the aim of providing adequate advance warnings of imminent eruptions to nearby populations. Also, a better modern-day understanding of volcanology has led to some better informed governmental and public responses to unanticipated volcanic activities. While the science of volcanology may not yet be capable of predicting the exact times and dates of eruptions far into the future, on suitably monitored volcanoes the monitoring of ongoing volcanic indicators is often capable of predicting imminent eruptions with advance warnings minimally of hours, and usually of days prior to any eruptions.<ref>[https://www.nationalgeographic.com/environment/article/volcano-safety-tips Volcano Safety Tips] {{Webarchive|url=https://web.archive.org/web/20220725072141/https://www.nationalgeographic.com/environment/article/volcano-safety-tips |date=July 25, 2022 }} National Geographic. By Maya Wei-Haas. 2015. Downloaded June 24, 2022.</ref> The diversity of volcanoes and their complexities mean that eruption forecasts for the foreseeable future will be based on [[Probability theory|probability]], and the application of [[risk management]]. Even then, some eruptions will have no useful warning. An example of this occurred in March 2017, when a tourist group was witnessing a presumed to be predictable Mount Etna eruption and the flowing lava came in contact with a snow accumulation causing a situational phreatic explosion causing injury to ten persons.<ref name=Thomaidis2021/> Other types of significant eruptions are known to give useful warnings of only hours at the most by seismic monitoring.<ref name=Castro2009/> The recent demonstration of a magma chamber with repose times of tens of thousands of years, with potential for rapid recharge so potentially decreasing warning times, under the youngest volcano in central Europe,<ref name="Cserép2023"/> does not tell us if more careful monitoring will be useful.

Scientists are known to perceive risk, with its social elements, differently from local populations and those that undertake social risk assessments on their behalf, so that both disruptive false alarms and retrospective blame, when disasters occur, will continue to happen.<ref>{{cite journal|last1=Donovan|first1=A|last2=Eiser|first2=JR|last3=Sparks|first3=RS|title=Scientists' views about lay perceptions of volcanic hazard and risk|journal=Journal of Applied Volcanology|year=2014|volume=3|issue=1|pages=1–14|doi=10.1186/s13617-014-0015-5|bibcode=2014JApV....3...15D|doi-access=free}}</ref>{{rp|pp=1–3}}

Thus in many cases, while volcanic eruptions may still cause major property destruction, the periodic large-scale loss of human life that was once associated with many volcanic eruptions, has recently been significantly reduced in areas where volcanoes are adequately monitored. This life-saving ability is derived via such volcanic-activity monitoring programs, through the greater abilities of local officials to facilitate timely evacuations based upon the greater modern-day knowledge of volcanism that is now available, and upon improved communications technologies such as cell phones. Such operations tend to provide enough time for humans to escape at least with their lives before a pending eruption. One example of such a recent successful volcanic evacuation was the [[Mount Pinatubo]] evacuation of 1991. This evacuation is believed to have saved 20,000 lives.<ref>[https://www.livescience.com/14603-pinatubo-eruption-20-anniversary.html Pinatubo: Why the Biggest Volcanic Eruption Wasn't the Deadliest] {{Webarchive|url=https://web.archive.org/web/20220719034051/https://www.livescience.com/14603-pinatubo-eruption-20-anniversary.html |date=July 19, 2022 }} LiveScience. By Stephanie Pappas. June 15, 2011.  Downloaded July 25, 2022.</ref> In the case of [[Mount Etna]], a 2021 review found 77 deaths due to eruptions since 1536 but none since 1987.<ref name=Thomaidis2021/>

Citizens who may be concerned about their own exposure to risk from nearby volcanic activity should familiarize themselves with the types of, and quality of, volcano monitoring and public notification procedures being employed by governmental authorities in their areas.<ref>[https://www.courthousenews.com/about-to-blow-are-we-ready-for-the-next-volcanic-catastrophe/ About to blow: Are we ready for the next volcanic catastrophe?] {{Webarchive|url=https://web.archive.org/web/20220817224316/https://www.courthousenews.com/about-to-blow-are-we-ready-for-the-next-volcanic-catastrophe/ |date=August 17, 2022 }} Courthouse News Service. By Candace Cheung.  August 17, 2022. Downloaded August 17, 2022.</ref>