Editing Yellowstone Caldera (section)

==Hazards==
===Earthquakes===
[[File:Yellowstone_earthquakes_history.svg|thumb|upright=1.7|Incidence of earthquakes in Yellowstone National Park region (1973–2014)<ref>{{cite web|url=http://www.quake.utah.edu/EQCENTER/LISTINGS/OTHER/yellowregion.htm|title=Yellowstone National Park Earthquake listings|access-date=April 20, 2013}}</ref>]]
Volcanic and tectonic actions in the region cause between 1,000 and 2,000 measurable [[earthquake]]s annually. Most are relatively minor, measuring [[Moment magnitude scale|magnitude]] 3 or weaker. Occasionally, numerous earthquakes are detected in a relatively short period of time, an event known as an [[earthquake swarm]]. In 1985, more than 3,000 earthquakes were measured over a period of several months. More than 70 smaller swarms were detected between 1983 and 2008. The USGS states these swarms are likely caused by slips on pre-existing faults rather than by movements of magma or [[hydrothermal]] fluids.<ref>{{cite web|url=http://volcanoes.usgs.gov/yvo/publications/2004/apr04swarm.php|title=Yellowstone Earthquake Swarms|publisher=[[Yellowstone Volcano Observatory]]|access-date=January 1, 2009}}</ref><ref name="volcanoes.usgs.gov">{{cite web|url=http://volcanoes.usgs.gov/activity/archiveupdate.php?noticeid=5199|title=January 2010 Yellowstone Seismicity Summary|access-date=February 1, 2010}}</ref>

In December 2008, continuing into January 2009, more than 500 earthquakes were detected under the northwest end of Yellowstone Lake over a seven-day span, with the largest registering a magnitude of 3.9.<ref>{{Cite web|url=https://volcanoes.usgs.gov/observatories/yvo/|title=Yellowstone Volcano Observatory|publisher=United States Geological Survey|access-date=April 29, 2020}}</ref><ref>{{cite web|url=http://www.seis.utah.edu/helicorder/heli/yellowstone/Uuss.LKWY_SHZ_US.2008123100.gif|title=UUSS Webicorder (Seismogram) at Lake for December 31, 2008|access-date=January 1, 2009}}</ref> Another swarm started in January 2010, after the [[2010 Haiti earthquake|Haiti earthquake]] and before the [[2010 Chile earthquake|Chile earthquake]]. With 1,620 small earthquakes between January 17, 2010, and February 1, 2010, this swarm was the second-largest ever recorded in the Yellowstone Caldera. The largest of these shocks was a magnitude 3.8 that occurred on January 21, 2010.<ref name="volcanoes.usgs.gov"/><ref>{{cite news|url=https://www.nytimes.com/2010/02/01/science/01yellowstone.html?partner=rss&emc=rss|title=Hundreds of Quakes Are Rattling Yellowstone|access-date=January 23, 2014 | work=The New York Times | first=Kirk | last=Johnson | date=January 31, 2010}}</ref> This swarm subsided to background levels by February 21. On March 30, 2014, at 6:34 AM [[Mountain Standard Time|MST]], a magnitude 4.8 earthquake struck Yellowstone, the largest recorded there since February 1980.<ref>{{cite news|last=Zuckerman|first=Laura|title=Yellowstone National Park rattled by largest earthquake in 34 years|url=https://www.reuters.com/article/us-usa-earthquake-yellowstone-idUSBREA2U01920140331|agency=Reuters|access-date=March 31, 2014}}<br/>{{cite news |last=Gedeon |first=Jacqueline |date=March 31, 2014 |title=4.8 magnitude earthquake hits Yellowstone National Park |url=http://nbcmontana.com/news/local/4-8-magnitude-earthquake-hits-yellowstone-national-park |work=KECI |location=Montana |access-date=April 4, 2018 }}</ref> In February 2018, more than 300 earthquakes occurred, with the largest being a magnitude 2.9.<ref>{{cite news |last=Zachos |first=Elaina |date=February 21, 2018 |title=Earthquake Swarms Are Shaking Yellowstone's Supervolcano. Here's What That Means. |url=https://news.nationalgeographic.com/2018/02/yellowstone-national-park-supervolcano-earthquake-swarms-spd/ |archive-url=https://web.archive.org/web/20180222033956/https://news.nationalgeographic.com/2018/02/yellowstone-national-park-supervolcano-earthquake-swarms-spd/ |url-status=dead |archive-date=February 22, 2018 |work=National Geographic |access-date=April 4, 2018 }}<br/>{{cite magazine |last=Bartels |first=Meghan |date=February 20, 2018 |title=Yellowstone Supervolcano Earthquake Swarm Hits 200 Shakes in Less Than Two Weeks |url=http://www.newsweek.com/yellowstone-supervolcano-earthquake-swarm-hits-200-shakes-less-two-weeks-812813 |magazine=Newsweek |access-date=April 4, 2018 }}</ref>

===Volcanoes===
[[File:Yellowstone Caldera.svg|thumb|upright=1.7|Diagram of the Yellowstone Caldera]]
The Lava Creek eruption of the Yellowstone Caldera, which occurred 640,000 years ago,<ref>{{cite web| title = Undine Falls, Lava Creek, Yellowstone National Park| publisher = United States Geological Survey| url = http://volcanoes.usgs.gov/yvo/images/20010519-082_caption.html| access-date = January 2, 2009}}</ref> ejected approximately {{convert|1000|km3|mi3}} of rock, dust and [[volcanic ash]] into the atmosphere. It was Yellowstone's third and most recent caldera-forming eruption.

Geologists closely monitor the elevation of the [[Yellowstone Plateau]], which has been rising as quickly as {{convert|150|mm|in}} per year, as an indirect measurement of changes in magma chamber pressure.<ref>{{cite web |author=Timmer |first=John |date=November 8, 2007 |title=Yellowstone recharges |url=https://arstechnica.com/journals/science.ars/2007/11/08/yellowstone-recharges |access-date=November 8, 2007 |work=arstechnica.com}}</ref><ref>{{cite press release |last1=Smith |first1=Robert B. |first2=Wu-Lung |last2=Chang |first3=Lee |last3=Siegel |title=Yellowstone rising: Volcano inflating with molten rock at record rate |publisher=University of Utah Public Relations |via=EurekAlert! (American Association for the Advancement of Science) |date=November 8, 2007 |url=http://eurekalert.org/pub_releases/2007-11/uou-yr103007.php|url-access=<!--WP:URLACCESS--> }}</ref><ref>{{cite journal |last1=Chang |first1=W.-L. |last2=Smith |first2=R. B. |last3=Wicks |first3=C. |last4=Farrell |first4=J. M. |last5=Puskas |first5=C. M. |title=Accelerated Uplift and Magmatic Intrusion of the Yellowstone Caldera, 2004 to 2006 |journal=Science |date=November 9, 2007 |volume=318 |issue=5852 |pages=952–956 |doi=10.1126/science.1146842|pmid=17991858 |bibcode=2007Sci...318..952C |s2cid=22478071 }}</ref>

The upward movement of the Yellowstone caldera floor between 2004 and 2008—almost {{convert|75|mm|in}} each year—was more than three times greater than ever observed since such measurements began in 1923.<ref>{{Cite web |title=Molten Rock Fills Yellowstone Volcano at Record Rate |url=https://www.newswise.com/articles/molten-rock-fills-yellowstone-volcano-at-record-rate |access-date=April 15, 2024 |website=newswise.com |language=en}}</ref> From 2004 to 2008, the land surface within the caldera moved upward as much as {{convert|8|in|cm}} at the White Lake GPS station.<ref>{{cite web| title = Recent ups and downs of the Yellowstone Caldera | work = [[Yellowstone Volcano Observatory]] | publisher = United States Geological Survey | date = September 28, 2008 | url = http://volcanoes.usgs.gov/yvo/publications/2007/upsanddowns.php | access-date = December 31, 2008}}</ref><ref>{{Cite journal |last1=Smith |first1=Robert B. |last2=Jordan |first2=Michael |last3=Steinberger |first3=Bernhard |last4=Puskas |first4=Christine M. |last5=Farrell |first5=Jamie |last6=Waite |first6=Gregory P. |last7=Husen |first7=Stephan |last8=Chang |first8=Wu-Lung |last9=O'Connell |first9=Richard |date=November 20, 2009 |title=Geodynamics of the Yellowstone hotspot and mantle plume: Seismic and GPS imaging, kinematics and mantle flow |journal=Journal of Volcanology and Geothermal Research |volume=188 |issue=1–3 |pages=26–56 |doi=10.1016/j.jvolgeores.2009.08.020 |url=http://www.uusatrg.utah.edu/PAPERS/smith_jvgr2009complete.pdf |bibcode=2009JVGR..188...26S }}</ref> In January 2010, the USGS stated that "uplift of the Yellowstone Caldera has slowed significantly"<ref>[http://volcano.wr.usgs.gov/yvostatus.php Current Alerts for U.S. Volcanoes]. volcano.wr.usgs.gov</ref> and that uplift continues but at a slower pace.<ref>[https://web.archive.org/web/20090405033306/http://pboweb.unavco.org/shared/scripts/stations/?checkkey=WLWY&sec=timeseries_plots&timeseries=raw GPS Station: WLWY – Data Products – Time Series Plots]. unavco.org</ref> USGS, University of Utah and National Park Service scientists with the [[Yellowstone Volcano Observatory]] maintain that they "see no evidence that another such cataclysmic eruption will occur at Yellowstone in the foreseeable future. Recurrence intervals of these events are neither regular nor predictable." This conclusion was reiterated in December 2013 in the aftermath of the publication of a study by University of Utah scientists finding that the "size of the magma body beneath Yellowstone is significantly larger than had been thought". The Yellowstone Volcano Observatory issued a statement on its website stating:
<blockquote>
Although fascinating, the new findings do not imply increased geologic hazards at Yellowstone, and certainly do not increase the chances of a "supereruption" in the near future. Contrary to some media reports, Yellowstone is not "overdue" for a supereruption.<ref>{{cite press release |date= December 19, 2013 |title= Monitoring Upgrades Result in New Insight into Yellowstone's Magma System |url= http://volcanoes.usgs.gov/observatories/yvo/yvo_news_archive.html |publisher= [[Yellowstone Volcano Observatory]] (USGS) |access-date= January 2, 2014 |archive-date= March 4, 2016 |archive-url= https://web.archive.org/web/20160304093639/http://volcanoes.usgs.gov/observatories/yvo/yvo_news_archive.html |url-status= dead |url-access= <!--WP:URLACCESS--> }}</ref>
</blockquote>
Media reports were more hyperbolic in their coverage.<ref>{{cite web |last=Burnett |first=Jim |date=January 1, 2014 |title= Reactions To Yellowstone Supervolcano Study Ranged From Hysteria To Ho-Hum |url=http://www.nationalparkstraveler.com/2014/01/reactions-yellowstone-supervolcano-study-ranged-hysteria-ho-hum24449 |website=National Parks Traveller |access-date=January 2, 2014 }}</ref>

A study published in ''GSA Today'', the monthly news and science magazine of the [[Geological Society of America]], identified three fault zones where future eruptions are most likely to be centered.<ref name="NG">{{cite magazine |author=Lovett |first=Richard A. |date=September 20, 2012 |title=Yellowstone Supervolcano Discovery—Where Will It Erupt? |url=https://www.nationalgeographic.com/science/article/120920-yellowstone-supervolcano-prediction-volcanoes-science-environment |url-status=dead |archive-url=https://web.archive.org/web/20210628130602/https://www.nationalgeographic.com/science/article/120920-yellowstone-supervolcano-prediction-volcanoes-science-environment |archive-date=June 28, 2021 |magazine=National Geographic}}</ref> Two of those areas are associated with lava flows aged 174,000–70,000 years ago, and the third is a focus of present-day [[seismicity]].<ref name=NG />

In 2017, [[NASA]] conducted a study to determine the feasibility of preventing the volcano from erupting. The results suggested that cooling the magma chamber by 35 percent would be enough to forestall such an incident. NASA proposed introducing water at high pressure 10 kilometers underground. The circulating water would release heat at the surface, possibly in a way that could be used as a [[geothermal power]] source. If enacted, the plan would cost about $3.46 billion. Brian Wilcox of the [[Jet Propulsion Laboratory]] observes that such a project could incidentally trigger an eruption if the top of the chamber is drilled into.<ref>{{Cite web|url=https://www.bbc.com/future/article/20170817-nasas-ambitious-plan-to-save-earth-from-a-supervolcano|title=Nasa's ambitious plan to save Earth from a supervolcano|first=David|last=Cox|publisher=BBC|access-date=April 29, 2020}}</ref><ref>{{Cite web|url=https://www.discovermagazine.com/planet-earth/no-nasa-isnt-going-to-drill-to-stop-yellowstone-from-erupting|title=No, NASA Isn't Going to Drill to Stop Yellowstone from Erupting|website=Discover Magazine|access-date=April 29, 2020}}</ref>

According to analysis of [[Seismic wave|earthquake data]] in 2013, the magma chamber is {{convert|80|km|abbr=on}} long and {{convert|20|km|abbr=on}} wide. It also has {{convert|4000|km3|abbr=on}} underground volume, of which 6–8% is filled with molten rock. This is about 2.5 times bigger than scientists had previously imagined; however, scientists believe that the proportion of molten rock in the chamber is too low to allow for another supereruption.<ref>{{cite journal |last1=Witze |first1=Alexandra |year=2013 |title=Large magma reservoir gets bigger |journal=Nature |doi=10.1038/nature.2013.14036 |s2cid=130449188}}</ref><ref>{{cite web |title=USGS: Volcano Hazards Program – Yellowstone Volcano Observatory Featured Articles Archive |url=http://volcanoes.usgs.gov/observatories/yvo/yvo_news_archive.html |url-status=dead |archive-url=https://web.archive.org/web/20160304093639/http://volcanoes.usgs.gov/observatories/yvo/yvo_news_archive.html |archive-date=March 4, 2016 |access-date=April 4, 2014}}</ref><ref>{{cite web |title=Discovery of Ancient Super-eruptions Suggests the Yellowstone Hotspot May Be Waning (USGS Release Date: JUNE 29, 2020) |url=https://www.usgs.gov/center-news/discovery-ancient-super-eruptions-suggests-yellowstone-hotspot-may-be-waning?qt-news_science_products=4#qt-news_science_products |access-date=February 16, 2021}}</ref>

In October 2017, research from [[Arizona State University]] indicated prior to Yellowstone's last supereruption, magma surged into the magma chamber in two large influxes. An analysis of crystals from Yellowstone's lava showed that prior to the last supereruption, the magma chamber underwent a rapid increase in temperature and change in composition. The analysis indicated that Yellowstone's magma reservoir can reach eruptive capacity and trigger a super-eruption within just decades, not centuries as volcanologists had originally thought.<ref name="may erupt sooner">{{cite web |author=Aceves |first=Ana |date=October 12, 2017 |title=Yellowstone Supervolcano May Erupt Sooner Than Anticipated |url=https://www.pbs.org/wgbh/nova/article/yellowstone-supervolcano-may-erupt-sooner-than-anticipated/ |access-date=March 12, 2021 |publisher=PBS}}</ref><ref name="seek clues">{{cite web |author=Diebel |first=Matthew |date=October 16, 2017 |title=Scientists seek clues to what triggered past Yellowstone 'supervolcano' eruptions |url=https://www.usatoday.com/story/news/nation/2017/10/12/yellowstone-supervolcano-research-finds-what-triggered-eruption/757337001/ |access-date=March 12, 2021 |work=USA Today}}</ref>

===Hydrothermal explosions===
{{Further|Hydrothermal explosion}}
[[Image:HotspotsSRP update2013.JPG|thumb|upright=1.4|Path of the Yellowstone hotspot over the past 16 million years]]

The volcanic eruptions, as well as the continuing geothermal activity, are a result of a great [[mantle plume|plume]] of magma located below the caldera's surface. The magma in this plume contains gases that are kept dissolved by the immense pressure under which the magma is contained. If the pressure is released to a sufficient degree by some geological shift, then some of the gases bubble out and cause the magma to expand. This can cause a chain reaction. If the expansion results in further relief of pressure, for example, by blowing crust material off the top of the chamber, the result is a very large gas explosion.{{Citation needed|date=September 2021}}

Studies and analysis may indicate that the greater hazard comes from hydrothermal activity which occurs independently of volcanic activity.{{citation needed|date=September 2021}} Over 20 large craters have been produced in the past 14,000 years, resulting in such features as Mary Bay, [[Turbid Lake]], and Indian Pond, which was created in an eruption about 1300 BC.{{citation needed|date=September 2021}}

In a 2003 report, USGS researchers proposed that an earthquake may have displaced more than {{convert|77|Mcuft|m3 gal|abbr=}} of water in Yellowstone Lake, creating colossal waves that unsealed a capped geothermal system and led to the hydrothermal explosion that formed Mary Bay.<ref>{{cite web| title = Frequently asked questions about recent findings at Yellowstone Lake| work = Yellowstone Volcano Observatory| publisher = United States Geological Survey| date = September 11, 2008| url = http://volcanoes.usgs.gov/yvo/publications/2003/LakeQA.php| access-date = December 31, 2008}}</ref><ref>{{cite news| title = Tsunami linked to Yellowstone crater| newspaper = [[USA Today]]| date = January 14, 2008| url = https://www.usatoday.com/tech/science/2008-01-14-tsunami-yellowstone_N.htm| access-date = December 31, 2008}}</ref>

Further research shows that very distant earthquakes reach and have effects upon the activities at Yellowstone, such as the 1992 7.3 magnitude [[1992 Landers earthquake|Landers earthquake]] in [[California]]'s [[Mojave Desert]] that triggered a swarm of quakes from more than {{convert|800|mi|km}} away, and the 2002 7.9 magnitude [[2002 Denali earthquake|Denali fault earthquake]] {{convert|2000|mi|km}} away in [[Alaska]] that altered the activity of many geysers and hot springs for several months afterward.<ref>{{cite news| title = Quake in Alaska Changed Yellowstone Geysers| publisher = [[University of Utah]]| date = May 27, 2004| url = http://unews.utah.edu/p/?r=030306-10| access-date = December 31, 2008}}</ref>

In 2016, the USGS announced plans to map the subterranean systems responsible for feeding the area's hydrothermal activity. According to the researchers, these maps could help predict when another eruption occurs.<ref>{{cite web|title=We're About to Find Out What's Rumbling Below The Yellowstone Supervolcano|url=http://www.sciencealert.com/we-re-about-to-find-out-what-s-rumbling-below-the-yellowstone-supervolcano|website=Science Alert|date=November 16, 2016 |access-date=May 22, 2017}}</ref>