Editing Yellowstone Caldera (section)

===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>