Supervolcano

For other uses, see Supervolcano (disambiguation).

World map of known VEI 7 and VEI 8 volcanoes
  VEI 8 (supervolcanoes)
  VEI 7

A supervolcano is a volcano that has had an eruption with a volcanic explosivity index (VEI) of 8,[1] the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers (240 cubic miles).[2]

Location of Yellowstone hotspot over time. Numbers indicate millions of years before the present.
Satellite image of Lake Toba, the site of a VEI 8 eruption c. 75,000 years ago
Cross-section through Long Valley Caldera

Supervolcanoes occur when magma in the mantle rises into the crust but is unable to break through it. Pressure builds in a large and growing magma pool until the crust is unable to contain the pressure and ruptures. This can occur at hotspots (for example, Yellowstone Caldera) or at subduction zones (for example, Toba).[3][4]

Large-volume supervolcanic eruptions are also often associated with large igneous provinces, which can cover huge areas with lava and volcanic ash. These can cause long-lasting climate change (such as the triggering of a small ice age) and threaten species with extinction. The Oruanui eruption of New Zealand's Taupō Volcano (about 25,600 years ago) was the world's most recent VEI-8 eruption.[5]

  1. ^ de Silva, Shanaka (2008). "Arc magmatism, calderas, and supervolcanos". Geology. 36 (8): 671. Bibcode:2008Geo....36..671D. doi:10.1130/focus082008.1.
  2. ^ "Questions About Supervolcanoes". Volcanic Hazards Program. USGS Yellowstone Volcano Observatory. 21 August 2015. Archived from the original on 3 July 2017. Retrieved 22 August 2017.
  3. ^ Wotzlaw, Jörn-Frederik; Bindeman, Ilya N.; Watts, Kathryn E.; Schmitt, Axel K.; Caricchi, Luca; Schaltegger, Urs (September 2014). "Linking rapid magma reservoir assembly and eruption trigger mechanisms at evolved Yellowstone-type supervolcanoes". Geology. 42 (9): 807–810. Bibcode:2014Geo....42..807W. doi:10.1130/g35979.1. ISSN 1943-2682.
  4. ^ Budd, David A.; Troll, Valentin R.; Deegan, Frances M.; Jolis, Ester M.; Smith, Victoria C.; Whitehouse, Martin J.; Harris, Chris; Freda, Carmela; Hilton, David R.; Halldórsson, Sæmundur A.; Bindeman, Ilya N. (25 January 2017). "Magma reservoir dynamics at Toba caldera, Indonesia, recorded by oxygen isotope zoning in quartz". Scientific Reports. 7 (1): 40624. Bibcode:2017NatSR...740624B. doi:10.1038/srep40624. ISSN 2045-2322. PMC 5264179. PMID 28120860.
  5. ^ Wilson, C. J. N. (2001). "The 26.5ka Oruanui eruption, New Zealand: An introduction and overview". Journal of Volcanology and Geothermal Research. 112 (1–4): 133–174. Bibcode:2001JVGR..112..133W. doi:10.1016/S0377-0273(01)00239-6.