<P> In a volcanic eruption, lava, volcanic bombs and ash, and various gases are expelled from a volcanic vent or fissure . While many eruptions only pose dangers to the immediately surrounding area, Earth's largest eruptions can have a major regional or even global impact, with some affecting the climate and contributing to mass extinctions . Volcanic eruptions can generally be characterized as either explosive eruptions, sudden ejections of rock and ash, or effusive eruptions, relatively gentle outpourings of lava . A separate list is given below for each type . </P> <P> There have probably been many such eruptions during Earth's history beyond those shown in these lists . However erosion and plate tectonics have taken their toll, and many eruptions have not left enough evidence for geologists to establish their size . Even for the eruptions listed here, estimates of the volume erupted can be subject to considerable uncertainty . </P> <P> In explosive eruptions, the eruption of magma is driven by the rapid release of pressure, often involving the explosion of gas previously dissolved within the material . The most famous and destructive historical eruptions are mainly of this type . An eruptive phase can consist of a single eruption, or a sequence of several eruptions spread over several days, weeks or months . Explosive eruptions usually involve thick, highly viscous, silicic or felsic magma, high in volatiles like water vapor and carbon dioxide . Pyroclastic materials are the primary product, typically in the form of tuff . Eruptions the size of that at Lake Toba 74,000 years ago, at least 2,800 cubic kilometres (670 cu mi), or the Yellowstone eruption 620,000 years ago, around 1,000 cubic kilometres (240 cu mi), occur worldwide every 50,000 to 100,000 years . </P> <Table> <Tr> <Th> Volcano--eruption </Th> <Th> Age (Millions of years) </Th> <Th> Location </Th> <Th> Volume (km) </Th> <Th> Notes </Th> <Th> Refs </Th> </Tr> <Tr> <Td> Guarapuava--Tamarana--Sarusas </Td> <Td> 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 8,600 </Td> <Td> Existence as a single volcano is controversial . Possibly a volcano chain . </Td> <Td> </Td> </Tr> <Tr> <Td> Santa Maria--Fria </Td> <Td> ~ 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 7,800 </Td> <Td> Existence as a single volcano is controversial . Possibly a volcano chain . </Td> <Td> </Td> </Tr> <Tr> <Td> Guarapuava--Ventura </Td> <Td> ~ 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 7,600 </Td> <Td> Existence as a single volcano is controversial . Possibly a volcano chain . </Td> <Td> </Td> </Tr> <Tr> <Td> Sam Ignimbrite and Green Tuff </Td> <Td> 29.5 </Td> <Td> Yemen </Td> <Td> 6,800 </Td> <Td> Volume includes 5550 km3 of distal tuffs . This estimate is uncertain to a factor of 2 or 3 . </Td> <Td> </Td> </Tr> <Tr> <Td> Goboboseb--Messum volcanic centre--Springbok quartz latite unit </Td> <Td> 132 </Td> <Td> Paraná and Etendeka traps, Brazil and Namibia </Td> <Td> 6,340 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Caxias do Sul--Grootberg </Td> <Td> ~ 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 5,650 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> La Garita Caldera--Fish Canyon Tuff </Td> <Td> 27.8 </Td> <Td> San Juan volcanic field, Colorado </Td> <Td> 5,000 </Td> <Td> Part of at least 20 large caldera - forming eruptions in the San Juan volcanic field and surrounding area that formed around 26 to 35 Ma . </Td> <Td> </Td> </Tr> <Tr> <Td> Jacui--Goboboseb II </Td> <Td> ~ 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 4,350 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Ourinhos--Khoraseb </Td> <Td> ~ 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 3,900 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Jabal Kura'a Ignimbrite </Td> <Td> 29.6 </Td> <Td> Yemen </Td> <Td> 3,800 </Td> <Td> Volume estimate is uncertain to a factor of 2 or 3 . </Td> <Td> </Td> </Tr> <Tr> <Td> Windows Butte tuff </Td> <Td> 31.4 </Td> <Td> William's Ridge, central Nevada </Td> <Td> 3,500 </Td> <Td> Part of the Mid-Tertiary ignimbrite flare - up </Td> <Td> </Td> </Tr> <Tr> <Td> Anita Garibaldi--Beacon </Td> <Td> ~ 132 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 3,450 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Indian Peak Caldera Complex--Wah Wah Springs tuff </Td> <Td> 29.5 </Td> <Td> Eastern Nevada / Western Utah </Td> <Td> 3,200 </Td> <Td> Indian Peak Caldera Complex total volume over 10,000 cubic km, Wah Wah Springs tuff being the largest </Td> <Td> </Td> </Tr> <Tr> <Td> Oxaya ignimbrites </Td> <Td> 19 </Td> <Td> Chile </Td> <Td> 3,000 </Td> <Td> Really a regional correlation of many ignimbrites originally thought to be distinct </Td> <Td> </Td> </Tr> <Tr> <Td> Lund Tuff </Td> <Td> 29 </Td> <Td> Great Basin, United States </Td> <Td> 3,000 </Td> <Td> Similar in composition to the Fish Canyon Tuff </Td> <Td> </Td> </Tr> <Tr> <Td> Lake Toba--Youngest Toba Tuff </Td> <Td> 0.073 </Td> <Td> Sunda Arc, Indonesia </Td> <Td> 2,800 </Td> <Td> Largest known eruption on earth in at least the last million years, possibly responsible for a population bottleneck of the human species (see Toba catastrophe theory) </Td> <Td> </Td> </Tr> <Tr> <Td> Pacana Caldera--Atana ignimbrite </Td> <Td> </Td> <Td> Chile </Td> <Td> 2,800 </Td> <Td> Forms a resurgent caldera . </Td> <Td> </Td> </Tr> <Tr> <Td> Iftar Alkalb--Tephra 4 W </Td> <Td> 29.5 </Td> <Td> Afro - Arabian </Td> <Td> 2,700 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Yellowstone Caldera--Huckleberry Ridge Tuff </Td> <Td> 2.059 </Td> <Td> Yellowstone hotspot </Td> <Td> 2,450 </Td> <Td> Largest Yellowstone eruption on record </Td> <Td> </Td> </Tr> <Tr> <Td> Whakamaru </Td> <Td> 0.254 </Td> <Td> Taupo Volcanic Zone, New Zealand </Td> <Td> 2,000 </Td> <Td> Largest in the Southern Hemisphere in the Late Quaternary </Td> <Td> </Td> </Tr> <Tr> <Td> Palmas BRA - 21--Wereldsend </Td> <Td> 29.5 </Td> <Td> Paraná and Etendeka traps </Td> <Td> 1,900 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Kilgore tuff </Td> <Td> 4.3 </Td> <Td> Near Kilgore, Idaho </Td> <Td> 1,800 </Td> <Td> Last of the eruptions from the Heise volcanic field </Td> <Td> </Td> </Tr> <Tr> <Td> Sana'a Ignimbrite--Tephra 2W63 </Td> <Td> 29.5 </Td> <Td> Afro - Arabian </Td> <Td> 1,600 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Millbrig eruptions--Bentonites </Td> <Td> 454 </Td> <Td> England, exposed in Northern Europe and Eastern US </Td> <Td> 1,509 </Td> <Td> One of the oldest large eruptions preserved </Td> <Td> </Td> </Tr> <Tr> <Td> Blacktail tuff </Td> <Td> 6.5 </Td> <Td> Blacktail, Idaho </Td> <Td> 1,500 </Td> <Td> First of several eruptions from the Heise volcanic field </Td> <Td> </Td> </Tr> <Tr> <Td> Emory Caldera--Kneeling Nun tuff </Td> <Td> 33 </Td> <Td> Southwestern New Mexico </Td> <Td> 1,310 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Timber Mountain tuff </Td> <Td> 11.6 </Td> <Td> Southwestern Nevada </Td> <Td> 1,200 </Td> <Td> Also includes a 900 cubic km tuff as a second member in the tuff </Td> <Td> </Td> </Tr> <Tr> <Td> Paintbrush tuff (Topopah Spring Member) </Td> <Td> 12.8 </Td> <Td> Southwestern Nevada </Td> <Td> 1,200 </Td> <Td> Related to a 1000 cubic km tuff (Tiva Canyon Member) as another member in the Paintbrush tuff </Td> <Td> </Td> </Tr> <Tr> <Td> Bachelor--Carpenter Ridge tuff </Td> <Td> 28 </Td> <Td> San Juan volcanic field </Td> <Td> 1,200 </Td> <Td> Part of at least 20 large caldera - forming eruptions in the San Juan volcanic field and surrounding area that formed around 26 to 35 Ma </Td> <Td> </Td> </Tr> <Tr> <Td> Bursum--Apache Springs Tuff </Td> <Td> 28.5 </Td> <Td> Southern New Mexico </Td> <Td> 1,200 </Td> <Td> Related to a 1050 cubic km tuff, the Bloodgood Canyon tuff </Td> <Td> </Td> </Tr> <Tr> <Td> Taupo Volcano--Oruanui eruption </Td> <Td> 0.027 </Td> <Td> Taupo Volcanic Zone, New Zealand </Td> <Td> 1,170 </Td> <Td> Most recent VEI 8 eruption </Td> <Td> </Td> </Tr> <Tr> <Td> Huaylillas Ignimbrite </Td> <Td> 15 </Td> <Td> Bolivia </Td> <Td> 1,100 </Td> <Td> Predates half of the uplift of the central Andes </Td> <Td> </Td> </Tr> <Tr> <Td> Bursum--Bloodgood Canyon tuff </Td> <Td> 28.5 </Td> <Td> Southern New Mexico </Td> <Td> 1,050 </Td> <Td> Related to a 1200 cubic km tuff, the Apache Springs tuff </Td> <Td> </Td> </Tr> <Tr> <Td> Yellowstone Caldera--Lava Creek Tuff </Td> <Td> 0.639 </Td> <Td> Yellowstone hotspot </Td> <Td> 1,000 </Td> <Td> Last large eruption in the Yellowstone National Park area </Td> <Td> </Td> </Tr> <Tr> <Td> Cerro Galán </Td> <Td> </Td> <Td> Catamarca Province, Argentina </Td> <Td> 1,000 </Td> <Td> Elliptical caldera is ~ 35 km wide </Td> <Td> </Td> </Tr> <Tr> <Td> Paintbrush tuff (Tiva Canyon Member) </Td> <Td> 12.7 </Td> <Td> Southwestern Nevada </Td> <Td> 1,000 </Td> <Td> Related to a 1200 cubic km tuff (Topopah Spring Member) as another member in the Paintbrush tuff </Td> <Td> </Td> </Tr> <Tr> <Td> San Juan--Sapinero Mesa Tuff </Td> <Td> 28 </Td> <Td> San Juan volcanic field </Td> <Td> 1,000 </Td> <Td> Part of at least 20 large caldera - forming eruptions in the San Juan volcanic field and surrounding area that formed around 26 to 35 Ma </Td> <Td> </Td> </Tr> <Tr> <Td> Uncompahgre--Dillon & Sapinero Mesa Tuffs </Td> <Td> 28.1 </Td> <Td> San Juan volcanic field </Td> <Td> 1,000 </Td> <Td> Part of at least 20 large caldera - forming eruptions in the San Juan volcanic field and surrounding area that formed around 26 to 35 Ma </Td> <Td> </Td> </Tr> <Tr> <Td> Platoro--Chiquito Peak tuff </Td> <Td> 28.2 </Td> <Td> San Juan volcanic field </Td> <Td> 1,000 </Td> <Td> Part of at least 20 large caldera - forming eruptions in the San Juan volcanic field and surrounding area that formed around 26 to 35 Ma </Td> <Td> </Td> </Tr> <Tr> <Td> Mount Princeton--Wall Mountain tuff </Td> <Td> 35.3 </Td> <Td> Thirtynine Mile volcanic area, Colorado </Td> <Td> 1,000 </Td> <Td> Helped cause the exceptional preservation at Florissant Fossil Beds National Monument </Td> <Td> </Td> </Tr> </Table>

Magma from a highly explosive volcano is very
find me the text answering this question