Portal:Volcanoes
The Volcanoes portal
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. The process that forms volcanoes is called volcanism.
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, the Wells Gray-Clearwater volcanic field, and the 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 kilometres (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. Mars has significant volcanoes. 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...)
Selected article -
The Mount Cayley volcanic field (MCVF) is a remote volcanic zone on the South Coast of British Columbia, Canada, stretching 31 km (19 mi) from the Pemberton Icefield to the Squamish River. It forms a segment of the Garibaldi Volcanic Belt, the Canadian portion of the Cascade Volcanic Arc, which extends from Northern California to southwestern British Columbia. Most of the MCVF volcanoes were formed during periods of volcanism under sheets of glacial ice throughout the last glacial period. These subglacial eruptions formed steep, flat-topped volcanoes and subglacial lava domes, most of which have been entirely exposed by deglaciation. However, at least two volcanoes predate the last glacial period and both are highly eroded. The field gets its name from Mount Cayley, a volcanic peak located at the southern end of the Powder Mountain Icefield. This icefield covers much of the central portion of the volcanic field and is one of the several glacial fields in the Pacific Ranges of the Coast Mountains.
Eruptions along the length of the MCVF began between 1.6 and 5.3 million years ago. At least 23 eruptions have occurred throughout its eruptive history. This volcanic activity ranged from effusive to explosive, with magma compositions ranging from basaltic to rhyolitic. Because the MCVF has a high elevation and consists of a cluster of mostly high altitude, non-overlapping volcanoes, subglacial activity is likely to have occurred under less than 800 m (2,600 ft) of glacial ice. The style of this glaciation promoted meltwater escape during eruptions. The steep profile of the volcanic field and its subglacial landforms support this hypothesis. As a result, volcanic features in the MCVF that interacted with glacial ice lack rocks that display evidence of abundant water during eruption, such as hyaloclastite and pillow lava. (Full article...)
Did you know
- ... that the 60 million years old Carmelo Formation (pictured) is made out of thousands of layers of volcanic pebbles, sandstone and mudstone with fossils?
- ... that one of the activities that are possible at the Nevado de Toluca National Park is scuba diving in the two volcanic crater lakes?
- ... that the Popocatépetl volcano occasionally dumps ash on the municipality of Ozumba, Mexico?
- ... that in August 2001, the Galileo spacecraft flew through the sulfur dioxide gas plume of the Ionian volcano Thor?
- ... that the Garibaldi Volcanic Belt in southwestern British Columbia is the site of Canada's largest recorded Holocene explosive eruption 2,350 years ago at the Mount Meager massif?
- ... that most of the recent volcanism in New Zealand has been along the line of the Taupo Volcanic Zone and the Kermadec island arc?
- ... that the asphalt volcano is a rare submarine volcano composed of asphalt and erupting petroleum and methane instead of lava?
- ... that eruptions from Mahogany Mountain, a caldera volcano, produced rock formations in Leslie Gulch over 15 million years ago?
General images
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Satellite measurements of ash and aerosol emissions from Mount Pinatubo. (from Timeline of volcanism on Earth) -
Lava-flooded craters and large expanses of smooth volcanic plains on Mercury (from List of extraterrestrial volcanoes) -
A major eruption of Gran Canaria took place around 14 million years ago. (from Timeline of volcanism on Earth) -
TOMS sulfur dioxide from the June 15, 1991 eruption of Mount Pinatubo. (from Timeline of volcanism on Earth) -
Cross section diagram of Earth showing some settings for volcanism on the planet (from Volcanism) -
Phreatic explosion captured at the Main Crater of Taal Volcano in January 2020, from an installed IP camera of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) monitoring the volcano. (from Decade Volcanoes) -
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A gentle, or effusive, volcanic eruption, in which liquid material (lava) gently flows from a vent, in this case in south-eastern Hawai’i island (from Volcanism) -
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Diagram showing the scale of VEI correlation with total ejecta volume (from Types of volcanic eruptions) -
Sulfur dioxide emissions by volcanoes. Mount Pinatubo: 20 million tons of sulfur dioxide. (from Timeline of volcanism on Earth) -
Olympus Mons (Latin, "Mount Olympus"), located on the planet Mars, is the tallest known mountain in the Solar System. (from Volcanism) -
Eruption of mud at Dashgil mud volcano in Gobustan, Azerbaijan (from Volcanism) -
Colima Volcano eruption column, December 2016 (from Decade Volcanoes) -
Diagram of a Strombolian eruption. (key: 1. Ash plume 2. Lapilli 3. Volcanic ash rain 4. Lava fountain 5. Volcanic bomb 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Dike 10. Magma conduit 11. Magma chamber 12. Sill) Click for larger version. (from Types of volcanic eruptions) -
Diagram of a Hawaiian eruption. (key: 1. Ash plume 2. Lava fountain 3. Crater 4. Lava lake 5. Fumaroles 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version. (from Types of volcanic eruptions) -
Some features of volcanism found in Earth's crust (from Volcanism) -
Some of the eruptive structures formed during volcanic activity (counterclockwise): a Plinian eruption column, Hawaiian pahoehoe flows, and a lava arc from a Strombolian eruption (from Types of volcanic eruptions) -
Diagram of a Submarine eruption. (key: 1. Water vapor cloud 2. Water 3. Stratum 4. Lava flow 5. Magma conduit 6. Magma chamber 7. Dike 8. Pillow lava) Click to enlarge. (from Types of volcanic eruptions) -
An example of the lava arcs formed during Strombolian activity. This image is of Stromboli itself. (from Types of volcanic eruptions) -
Satellite animation of the initial ash plume and shockwave of the 2022 Hunga Tonga–Hunga Ha’apai eruption and tsunami. The massive explosive eruption was hundreds of times more powerful than the atomic bomb dropped on Hiroshima. (from Volcanism) -
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MLO transmission ratio - Solar radiation reduction due to volcanic eruptions (from Timeline of volcanism on Earth) -
The high initial temperatures of silicate lavas mean that they emit visible light before cooling. (from Volcanism) -
Diagrammatic representation of a plume on Enceladus (from Volcanism) -
Diagram of a phreatic eruption. (key: 1. Water vapor cloud 2. Magma conduit 3. Layers of lava and ash 4. Stratum 5. Water table 6. Explosion 7. Magma chamber) (from Types of volcanic eruptions) -
The lava spine that developed after the 1902 eruption of Mount Pelée (from Types of volcanic eruptions) -
Sarychev Peak: the sulphur dioxide cloud generated by the eruption on June 12, 2009 (in Dobson units). (from Timeline of volcanism on Earth) -
2016 eruption of Mount Sinabung (from Types of volcanic eruptions) -
Location of Mount Pinatubo, showing area over which ash from the 1991 eruption fell. (from Timeline of volcanism on Earth) -
Diagram of Peléan eruption. (key: 1. Ash plume 2. Volcanic ash rain 3. Lava dome 4. Volcanic bomb 5. Pyroclastic flow 6. Layers of lava and ash 7. Stratum 8. Magma conduit 9. Magma chamber 10. Dike) Click for larger version. (from Types of volcanic eruptions) -
The final eruptions in the creation of Banks Peninsula in New Zealand occurred about 9 million years ago. (from Timeline of volcanism on Earth) -
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Diagram of a Plinian eruption. (key: 1. Ash plume 2. Magma conduit 3. Volcanic ash rain 4. Layers of lava and ash 5. Stratum 6. Magma chamber) Click for larger version. (from Types of volcanic eruptions) -
VEI and ejecta volume correlation (from Timeline of volcanism on Earth)
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21 April 1990 eruptive column from Redoubt Volcano, as viewed to the west from the Kenai Peninsula (from Types of volcanic eruptions) -
Mount Lamington following the devastating 1951 eruption (from Types of volcanic eruptions) -
Diagram of a Vulcanian eruption. (key: 1. Ash plume 2. Lapilli 3. Lava fountain 4. Volcanic ash rain 5. Volcanic bomb 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version. (from Types of volcanic eruptions) -
A diagram of a Subglacial eruption. (key: 1. Water vapor cloud 2. Crater lake 3. Ice 4. Layers of lava and ash 5. Stratum 6. Pillow lava 7. Magma conduit 8. Magma chamber 9. Dike) Click for larger version. (from Types of volcanic eruptions) -
NASA, Global Dimming - El Chichon, VEI 5; Pinatubo, VEI 6. (from Timeline of volcanism on Earth) -
Lahar flows from the 1985 eruption of Nevado del Ruiz, which totally destroyed Armero in Colombia (from Types of volcanic eruptions) -
Diagram of a Surtseyan eruption. (key: 1. Water vapor cloud 2. Compressed ash 3. Crater 4. Water 5. Layers of lava and ash 6. Stratum 7. Magma conduit 8. Magma chamber 9. Dike) Click for larger version. (from Types of volcanic eruptions) -
Distribution of selected hotspots. The numbers in the figure are related to the listed hotspots on Hotspot (geology). (from Timeline of volcanism on Earth) -
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Selected biography -
Arturo Pineda Alcaraz (March 21, 1916 – March 10, 2001) was a Filipino volcanologist known for his work on geothermal energy. He received the 1982 Ramon Magsaysay Award for Government Service. (Full article...)
Selected picture
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Wildfire on the island of Hawaiʻi caused by pāhoehoe lava flowing on the coastal plain of Kīlauea. The new lava is moving across the old surface, which is covered with a roughly 1-inch (2.54 cm)-thick layer of moss. The burning moss generates the smoke visible in the image. This kind of fire cannot be easily prevented or suppressed.
Selected quote
"No one told us we needed a gas mask."
— Tourist visiting the highly active Ambrym volcano, South West Pacific.
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Featured work and other approved content
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.
What you can do
- Add the {{WikiProject Volcanoes}} message box to talk pages of articles within the scope of this project, including appropriate assessments, if needed.
- Add appropriate volcano type categories to articles, and verify the accuracy of any existing categories. See the section "Categorization" below.
- Add {{infobox mountain}} to articles if needed and missing, and add volcano-related fields to existing infoboxes if these are missing.
- Expand volcano articles which are stubs, especially by adding photos and (most importantly) proper references.
- Help improve articles related to Hawaiian and Canadian volcanism by joining the Hawaiian and Canadian workgroups.
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