Editing Volcanism (section)

====Phreatic eruption====
A [[phreatic eruption]] can occur when hot water under pressure is depressurised. Depressurisation reduces the boiling point of the water, so when depressurised the water suddenly boils.<ref name="ESKP">{{Cite journal |title=Dangerous water vapor: phreatic eruptions |url=https://www.eskp.de/en/basic-knowledge/natural-hazards/dangerous-water-vapour-phreatic-eruptions-935881/ |last=Strehlow |first=K. |journal=Earth Science Knowledge Platform |date=2016-11-22 |doi=10.2312/eskp.051 |access-date=2024-03-17}}</ref> Or it may happen when groundwater is suddenly heated, flashing to steam suddenly.<ref name="USGS">{{cite web |title=VHP Photo Glossary: Phreatic eruption |url=http://volcanoes.usgs.gov/images/pglossary/HydroVolcEruption.php |access-date=13 November 2010 |work=Volcano Hazards Program |publisher=U.S. Geological Survey}}</ref>
When water turns into steam in a phreatic eruption, it expands at supersonic speeds, up to 1,700 times its original volume. This can be enough to shatter solid rock, and hurl rock fragments hundreds of metres.<ref>{{Cite web |last=Cronin |first=Shane |date=December 9, 2019 |title=Steam-driven volcanic eruptions difficult to predict, still poorly understood |url=https://www.upi.com/Science_News/2019/12/09/Steam-driven-volcanic-eruptions-difficult-to-predict-poorly-understood/5221575896208/ |website=UPI.com |access-date=2024-03-17}}</ref>