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.
On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most 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 in the 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 the Earth's troposphere. Historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines. (Full article...)
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Mauna Loa (/ˌmɔːnə ˈloʊ.ə/ or /ˌmaʊnə ˈloʊ.ə/; Hawaiian: [ˈmɐwnə ˈlowə]; English: Long Mountain) is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean. The largest subaerial volcano (as opposed to subaqueous volcanoes) in both mass and volume, Mauna Loa has historically been considered the largest volcano on Earth, dwarfed only by Tamu Massif. It is an active shield volcano with relatively gentle slopes, with a volume estimated at 18,000 cubic miles (75,000 km3), although its peak is about 125 feet (38 m) lower than that of its neighbor, Mauna Kea. Lava eruptions from Mauna Loa are silica-poor and very fluid, and they tend to be non-explosive.
Mauna Loa has probably been erupting for at least 700,000 years, and may have emerged above sea level about 400,000 years ago. The oldest-known dated rocks are not older than 200,000 years. The volcano's magma comes from the Hawaii hotspot, which has been responsible for the creation of the Hawaiian island chain over tens of millions of years. The slow drift of the Pacific Plate will eventually carry Mauna Loa away from the hotspot within 500,000 to one million years from now, at which point it will become extinct. (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
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)
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 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)
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)
Diagram showing the scale of VEI correlation with total ejecta volume (from Types of volcanic eruptions)
Tavurvur in Papua New Guinea erupting (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)
Herðubreið, a tuya in Iceland (from Types of volcanic eruptions)
NASA, Global Dimming - El Chichon, VEI 5; Pinatubo, VEI 6. (from Timeline of volcanism on Earth)
Sulfur dioxide emissions by volcanoes. Mount Pinatubo: 20 million tons of sulfur dioxide. (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 Types of volcanic eruptions)
Teide, Tenerife (Spain). (from Decade Volcanoes)
Location of Mount Pinatubo, showing area over which ash from the 1991 eruption fell. (from Timeline of volcanism on Earth)
Lava-flooded craters and large expanses of smooth volcanic plains on Mercury (from List of extraterrestrial volcanoes)
Phreatic explosion captured at the Main Crater of Taal Volcano. Photo taken from the installed IP camera of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) monitoring the volcano. (from Decade Volcanoes)
Mount Lamington following the devastating 1951 eruption (from Types of volcanic eruptions)
TOMS sulfur dioxide from the June 15, 1991 eruption of Mount Pinatubo. (from Timeline of volcanism on Earth)
Satellite measurements of ash and aerosol emissions from Mount Pinatubo. (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 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)
21 April 1990 eruptive column from Redoubt Volcano, as viewed to the west from the Kenai Peninsula (from Types of volcanic eruptions)
Ropey pahoehoe lava from Kilauea, Hawaiʻi (from Types of volcanic eruptions)
Plate tectonics map with volcano locations indicated with red circles (from Volcanism)
The final eruptions in the creation of Banks Peninsula in New Zealand occurred about 9 million years ago. (from Timeline of volcanism on Earth)
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)
Galeras, Nariño, (Colombia). (from Decade Volcanoes)
Building destroyed by eruptions at Mount Unzen, Japan (from Decade Volcanoes)
A major eruption of Gran Canaria took place around 14 million years ago. (from Timeline of volcanism on Earth)
Pyroclastic flows at Mayon Volcano, Philippines, 1984 (from Types of volcanic eruptions)
MLO transmission ratio - Solar radiation reduction due to volcanic eruptions (from Timeline of volcanism on Earth)
VEI and ejecta volume correlation (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 Types of volcanic eruptions)
Lahar flows from the 1985 eruption of Nevado del Ruiz, which totally destroyed Armero in Colombia (from Types of volcanic eruptions)
Colima Volcano eruption column, December 2016 (from Decade Volcanoes)
Cross-section through a stratovolcano (vertical scale is exaggerated):(from Volcanism)- Large magma chamber
- Bedrock
- Conduit (pipe)
- Base
- Sill
- Dike
- Layers of ash emitted by the volcano
- Flank
- Layers of lava emitted by the volcano
- Throat
- Parasitic cone
- Lava flow
- Vent
- Crater
- Ash cloud
Sarychev Peak: the sulphur dioxide cloud generated by the eruption on June 12, 2009 (in Dobson units). (from Timeline of volcanism on Earth)
Distribution of selected hotspots. The numbers in the figure are related to the listed hotspots on Hotspot (geology). (from Timeline of volcanism on Earth)
An example of the lava arcs formed during Strombolian activity. This image is of Stromboli itself. (from Types of volcanic eruptions)
The lava spine that developed after the 1902 eruption of Mount Pelée (from Types of volcanic eruptions)
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"This ground is hot enough to cook the Sunday roast!"
— John Seach, remarking on his boots melting whilst on the slope of Lopevi Volcano, 2000
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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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