Portal:Volcanoes
The Volcanoes portal
A volcano is commonly defined as a vent or fissure 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 resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions. 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 most likely arises from upwelling diapirs from the core–mantle boundary called mantle plumes, 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism or intraplate volcanism, in which the plume may cause thinning of the crust and result in a volcanic island chain due to the continuous movement of the tectonic plate, of which the Hawaiian hotspot is an example. Volcanoes are usually not created at transform tectonic boundaries where two tectonic plates slide past one another.
Volcanoes, based on their frequency of eruption or volcanism, are referred to as either active or extinct. Active volcanoes have a history of volcanism and are likely to erupt again while extinct ones are not capable of eruption at all as they have no magma source. “Dormant” volcanoes have not erupted in a long time- generally accepted as since the start of the Holocene, about 12000 years ago- but may erupt again. These categories aren't entirely uniform; they may overlap for certain examples.
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 kilometres (19 miles) 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 metres (2,600 feet) 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 volcanic chain (pictured) responsible for creating the island of Hawaii extends all the way to the Kuril–Kamchatka Trench, at the border of Russia?
- ... that Nintoku Seamount, an underwater volcano in the Hawaiian–Emperor seamount chain, is over 56.2 million years old?
- ... that volcanoes in the Puyehue Volcano complex may have produced some of the most primitive magmas in the Andes?
- ... that Pilot Rock is one of the oldest volcanic formations in the Cascade Range?
- ... that one of a series of hotels called the Volcano House, built at the edge of Kīlauea volcano since 1846, burned to the ground from a kitchen fire?
- ... that the eruption of Amak Volcano in about 2550 BCE was confirmed by tephrochronology?
- ... that the Bobrof Volcano is an uninhabited island in the Andreanof Islands, part of Alaska's Aleutian archipelago?
- ... that the closest transportation to Davidof Volcano is 199 miles (320 km) away in Adak, Alaska?
General images
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Some features of volcanism found in Earth's crust (from Volcanism) -
Sulfur dioxide emissions by volcanoes. Mount Pinatubo: 20 million tons of sulfur dioxide. (from Timeline of volcanism on Earth) -
MLO transmission ratio - Solar radiation reduction due to volcanic eruptions (from Timeline of volcanism on Earth) -
2016 eruption of Mount Sinabung (from Volcanic eruption) -
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 Volcanic eruption) -
Mount Lamington following the devastating 1951 eruption (from Volcanic eruption) -
NASA, Global Dimming - El Chichon, VEI 5; Pinatubo, VEI 6. (from Timeline of volcanism on Earth) -
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) -
Eruption of mud at Dashgil mud volcano in Gobustan, Azerbaijan (from Volcanism) -
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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 Volcanic eruption) -
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Location of Mount Pinatubo, showing area over which ash from the 1991 eruption fell. (from Timeline of volcanism on Earth) -
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 Volcanic eruption) -
Colima Volcano eruption column, December 2016 (from Decade Volcanoes) -
Diagrammatic representation of a plume on Enceladus (from Volcanism) -
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21 April 1990 eruptive column from Redoubt Volcano, as viewed to the west from the Kenai Peninsula (from Volcanic eruption) -
Sarychev Peak: the sulphur dioxide cloud generated by the eruption on June 12, 2009 (in Dobson units). (from Timeline of volcanism on Earth) -
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A major eruption of Gran Canaria took place around 14 million years ago. (from Timeline of volcanism on Earth) -
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 Volcanic eruption) -
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 Volcanic eruption) -
The final eruptions in the creation of Banks Peninsula in New Zealand occurred about 9 million years ago. (from Timeline of volcanism on Earth) -
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 Volcanic eruption) -
Satellite measurements of ash and aerosol emissions from Mount Pinatubo. (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 Volcanic eruption) -
Distribution of selected hotspots. The numbers in the figure are related to the listed hotspots on Hotspot (geology). (from Timeline of volcanism on Earth) -
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 Volcanic eruption) -
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 Volcanic eruption) -
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 Volcanic eruption) -
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An example of the lava arcs formed during Strombolian activity. This image is of Stromboli itself. (from Volcanic eruption) -
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) -
Lahar flows from the 1985 eruption of Nevado del Ruiz, which totally destroyed Armero in Colombia (from Volcanic eruption) -
Lava-flooded craters and large expanses of smooth volcanic plains on Mercury (from List of extraterrestrial volcanoes) -
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) -
Olympus Mons (Latin, "Mount Olympus"), located on the planet Mars, is the tallest known mountain in the Solar System. (from Volcanism) -
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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) -
The high initial temperatures of silicate lavas mean that they emit visible light before cooling. (from Volcanism) -
VEI and ejecta volume correlation (from Timeline of volcanism on Earth)
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Selected biography -
William Henry Mathews (1919–2003) was a Canadian geologist, volcanologist, engineer, and professor. He is considered a pioneer in the study of subglacial eruptions and volcano-ice interactions in North America. Many of his publications continue to be regarded as classics in their field. (Full article...)
Selected picture
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Aerial view of Mount Kilimanjaro, the highest peak in Africa and the fourth highest of the Seven Summits. The volcano consists of three distinctive volcanic cones; of which the Kibo cone, pictured, is highest.
Selected quote
"We'll just look at you. If you looked scared then we'll panic."
— Discovery channel crew, talking to volcanologist John Seach during filming at Yasur Volcano, 2000.
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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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