Portal:Volcanoes

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Sabancaya volcano erupting, Peru in 2017
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, 3,000 kilometers (1,900 mi) deep within Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide past one another.

Large eruptions can affect atmospheric temperature as ash and droplets of sulfuric acid obscure the Sun and cool Earth's troposphere. Historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines.

Other planets besides Earth have volcanoes. For example, volcanoes are very numerous on Venus. In 2009, a paper was published suggesting a new definition for the word 'volcano' that includes processes such as cryovolcanism. It suggested that a volcano be defined as 'an opening on a planet or moon's surface from which magma, as defined for that body, and/or magmatic gas is erupted.'

This article mainly covers volcanoes on Earth. See § Volcanoes on other celestial bodies and Cryovolcano for more information. (Full article...)

Surtsey, sixteen days after the onset of the eruption

Surtsey ("Surtr's island" in Icelandic, Icelandic pronunciation: [ˈsʏr̥(t)sˌeiː] ) is an uninhabited volcanic island located in the Vestmannaeyjar archipelago off the southern coast of Iceland. At Surtsey is the southernmost point of Iceland. It was formed in a volcanic eruption which began 130 metres (430 feet) below sea level, and reached the surface on 14 November 1963. The eruption lasted until 5 June 1967, when the island reached its maximum size of 2.7 km2 (1.0 sq mi). Since then, wave erosion has caused the island to steadily diminish in size: , its surface area was 1.3 km2 (0.50 sq mi). The most recent survey (2007) shows the island's maximum elevation at 155 m (509 ft) above sea level.

The new island was named after Surtr, a fire jötunn or giant from Norse mythology. It was intensively studied by volcanologists during its eruption, and afterwards by botanists and other biologists as life forms gradually colonised the originally barren island. The undersea vents that produced Surtsey are part of the Vestmannaeyjar submarine volcanic system, part of the fissure of the sea floor called the Mid-Atlantic Ridge. Vestmannaeyjar also produced the famous eruption of Eldfell on the island of Heimaey in 1973. The eruption that created Surtsey also created a few other small islands along this volcanic chain, such as Jólnir and other, unnamed peaks. Most of these eroded away fairly quickly. It is estimated that Surtsey will remain above sea level until at least the year 2100. (Full article...)

Did you know

Colour image of Io's trailing hemisphere, highlighting the large red ring around the volcano Pele on Io

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The following are images from various volcano-related articles on Wikipedia.

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Grand Prismatic Spring
Grand Prismatic Spring
Credit: Carsten Steger

Aerial view of Grand Prismatic Spring in Yellowstone National Park. The spring is approximately 250 ft (76 m) by 300 ft (91 m) in size. The deep azure blue water in the center is sterile, and surrounded by a huge mat of algae and bacteria. The orange color is from the carotenoids they produce.

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"No one told us we needed a gas mask."

— Tourist visiting the highly active Ambrym volcano, South West Pacific.


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Featured articles: 1980 eruption of Mount St. Helens  • 2007–2008 Nazko earthquakes  • Amchitka  • Armero tragedy  • Craters of the Moon National Monument and Preserve  • Cerro Azul (Chile volcano)  • David A. Johnston  • Enceladus (moon)  • Geology of the Lassen volcanic area  • Io (moon)  • Kamaʻehuakanaloa Seamount  • Mauna Kea  • Mauna Loa  • Metacomet Ridge  • Mono-Inyo Craters  • Mount Cayley volcanic field  • Mount St. Helens  • Mount Tambora  • Nevado del Ruiz  • Surtsey  • The Volcano (British Columbia)  • Triton (moon)  • Upper and Lower Table Rock  • Volcanism on Io  • Volcano (South Park)  • Yellowstone National Park

Featured lists: List of volcanoes in Indonesia  • List of volcanoes in the Hawaiian – Emperor seamount chain  • List of largest volcanic eruptions

Featured pictures: There are currently 43 volcano-related Featured pictures. A full gallery can be seen here.

Good articles: Abyssal plain  • Amak Volcano  • Anahim hotspot  • Axial Seamount  • Ben Nevis  • Bowie Seamount  • Crater Lake  • Davidson Seamount  • Ferdinandea  • Gareloi Volcano  • Geyser  • Glacier Peak  • Hawaii hotspot  • Hualālai  • Kohala (mountain)  • Lake Toba  • Minoan eruption  • Mount Adams (Washington)  • Mount Bailey  • Mount Baker  • Mount Cleveland (Alaska)  • Mount Edziza volcanic complex  • Mount Garibaldi  • Mount Hood  • Mount Kenya  • Mount Rainier  • Mount Redoubt  • Mount Tehama  • Mount Thielsen  • Mount Vesuvius  • Peter I Island  • Roxy Ann Peak  • Rùm  • Sakurajima  • Sangay  • Silverthrone Caldera  • Staffa  • Types of volcanic eruptions  • Volcanic ash  • Weh Island  • Wells Gray-Clearwater volcanic field  • Yamsay Mountain

Valued pictures: A gallery of volcano-related valued pictures can be seen here.

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  • Add the {{WikiProject Volcanoes}} message box to talk pages of articles within the scope of this project, including appropriate assessments, if needed.
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  • Expand volcano articles which are stubs, especially by adding photos and (most importantly) proper references.
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