Editing Natural disaster (section)

===Volcanic eruptions===
{{see also|Types of volcanic eruptions|List of largest volcanic eruptions}}
[[File:007_Volcano_eruption_of_Litli-Hrútur_in_Iceland_in_2023_Video_by_Giles_Laurent.webm|thumb|Video of lava agitating and bubbling in the volcano eruption of Litli-Hrútur, 2023]]
[[Volcano]]es can cause widespread destruction and consequent disaster in several ways. One hazard is the [[Types of volcanic eruptions|volcanic eruption]] itself, with the force of the explosion and falling rocks able to cause harm. [[Lava]] may also be released during the eruption of a volcano; as it leaves the volcano, it can destroy buildings, plants and animals due to its extreme heat. In addition, [[volcanic ash]] may form a cloud (generally after cooling) and settle thickly in nearby locations. When mixed with water, this forms a concrete-like material. In sufficient quantities, ash may cause roofs to collapse under its weight. Even small quantities will harm humans if inhaled – it has the consistency of ground glass and therefore causes laceration to the throat and lungs. Volcanic ash can also cause abrasion damage to moving machinery such as engines. The main killer of humans in the immediate surroundings of a volcanic eruption is [[pyroclastic flows]], consisting of a cloud of hot ash which builds up in the air above the volcano and rushes down the slopes when the eruption no longer supports the lifting of the gases. It is believed that [[Pompeii]] was destroyed by a pyroclastic flow. A [[lahar]] is a volcanic mudflow or landslide. The 1953 [[Tangiwai disaster]] was caused by a lahar, as was the 1985 [[Armero tragedy]] in which the town of Armero was buried and an estimated 23,000 people were killed.{{Citation needed|date=December 2020}}

Volcanoes rated at 8 (the highest level) on the [[volcanic explosivity index]] are known as [[supervolcano]]es. According to the [[Toba catastrophe theory]], 75,000 to 80,000 years ago, a supervolcanic eruption at what is now [[Lake Toba]] in [[Sumatra]] reduced the human population to 10,000 or even 1,000 breeding pairs, creating a bottleneck in human evolution,<ref>{{cite news |last1=Gibbons |first1=Ann |title=Human Ancestors Were an Endangered Species |url=https://www.science.org/content/article/human-ancestors-were-endangered-species |work=Science |publisher=AAAS |date=19 January 2010 |access-date=29 December 2020 |archive-date=8 December 2020 |archive-url=https://web.archive.org/web/20201208042514/https://www.sciencemag.org/news/2010/01/human-ancestors-were-endangered-species |url-status=live }}</ref> and killed three-quarters of all plant life in the northern hemisphere. However, there is considerable debate regarding the veracity of this theory. The main danger from a supervolcano is the immense cloud of ash, which has a disastrous global effect on climate and temperature for many years.