The Volcanoes Portal

A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

Volcanoes are generally found where tectonic plates are pulled apart or come together. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by "divergent tectonic plates" pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by "convergent tectonic plates" coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.

Volcanoes can be caused by "mantle plumes". These so-called "hotspots" , for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.

Selected article

The Metacomet Ridge of southern New England is a narrow and steep fault-block mountain ridge known for its extensive cliff faces, scenic vistas, microclimate ecosystems, and communities of plants considered rare or endangered. An important recreation resource located within 10 miles (16 km) of a population corridor of over 2.5 million people, the ridge is home to four long distance hiking trails and over a dozen parks and recreation areas including several state and nationally recognized historic sites. Because of its natural, historic, and recreational value, the ridge has been the focus of ongoing conservation efforts involving municipal, state, and national agencies as well as nearly two dozen non-profit organizations. The Metacomet Ridge extends from New Haven and Branford, Connecticut on Long Island Sound, through the Connecticut River Valley region of Massachusetts, to northern Franklin County, 2 miles (3.2 km), short of the Vermont and New Hampshire borders, a distance of 100 miles (160 km). Younger and geologically distinct from the nearby Appalachian Mountains and surrounding uplands, the Metacomet Ridge is composed of volcanic basalt, also known as traprock, and sedimentary rock in faulted and tilted layers many hundreds of feet thick. In most, but not all cases, the basalt layers are dominant, prevalent, and exposed.

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Selected biography

Howel Williams (1898-1980) was a noted American geologist and volcanologist. He was born of Welsh parents in Liverpool, England, on October 12, 1898. He received a BA in geography in 1923 and an MA in archaeology in 1924 from Liverpool University. He studied geology at the Imperial College of Science and Technology in London. In 1926 he moved to the University of California at Berkeley in 1926. In 1928 he was awarded the degree of D.Sc. from the University of Liverpool and published his first papers on the geology of various California volcanic regions.

He published many studies on the volcanoes of California, but is most noted for his "The Geology of Crater Lake National Park" in which he recognized the nature of the collapse of the crater and extended the work to develop the principles of volcanic caldera formation. He did extensive early work on the geology of Central America (often sketch-mapping from the windows of second-class buses), and of the Galapagos Islands. In Latin America, Williams put to good use his early background in archeology. For instance, he used petrographic techniques to trace the origin of stone used in the giant Olmec sculptures of La Venta, Tabasco Mexico.

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Did you know

• ...that the 1980 Mount St. Helens eruption (pictured) in Washington was the first major volcanic eruption to occur in the U.S. since the 1915 eruption of Lassen Peak in California?
• ...that the evolution of Hawaiian volcanoes ends with the Guyot Stage, and that most, if not all, the volcanoes west of Kure Atoll are guyots?
• ...that the Irazú Volcano in Costa Rica erupted violently in 1963, on the day U.S. President John F. Kennedy arrived in the country for a state visit?
• ...that Ferdinandea was a volcanic island near Sicily which was claimed by four countries when it appeared in 1831, but was destroyed by erosion less than a year later?
• ...that the Iceland hotspot is partly responsible for the frequent volcanic eruptions and geothermal activity experienced in Iceland?
• ...that the only active volcano in South Asia is on Barren Island, one of India's Andaman Islands?
• ...that Imbabura is an inactive stratovolcano in northern Ecuador which is revered in local folklore as a protective parent?
• ..that one submarine volcano located in Banda Sea of Indonesia is called the Emperor of China?

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Volcanoes news

News moniter

• 2 January 2009: Lava flows from Mount Nyamuragira threaten endangered chimpanzees in Virunga National Park and settlements south of the volcano.
• Thursday 24th December 2009: Activity continues to build up at Mayon Volcano, Philippines, following evacuation and the raising of the threat level to 4 out of 5.
• Sunday 20th December 2009: Gas released from Ambrym Volcano, Vanuatu, gives rise to vog in the region.
• Saturday 19th December 2009: A swarm of over 30 earthquakes occurs at Mount Etna, Italy, the largest of which is magnitude 4.6.
• 17th December 2009: Explosive eruption at Bezymianny Volcano, Kamchatka, Russia.

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Selected picture

Credit: Galileo spacecraft, NASA

False-color mosaic of the moon, constructed from a series of 53 images taken by Galileo spacecraft. Volcanic rock is shown as blue to orange shades.

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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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Collaboration of the Month

The current Collaboration of the month is Mount Shasta.

Every month a different volcano-related topic, stub or non-existent article may be picked. Please improve the article any way you can.

WikiProjects

• WikiProject Volcanoes
• WikiProject Seamounts
• WikiProject Mountains

Categories

Volcanoes topics

Core topics: Volcano  • Volcanology  • Igneous petrology  • Lava  • Magma  • Decade Volcanoes  • List of volcanoes  • Plate tectonics  • Hotspot

Types of volcanoes: Fissure vent  • Shield volcano  • Lava dome  • Cinder cone  • Stratovolcano  • Supervolcano  • Submarine volcano  • Subglacial volcano  • Mud volcano

Types of eruptions: Strombolian  • Vulcanian  • Peléan  • Hawaiian  • Surtseyan  • Plinian  • Submarine  • Subglacial  • Phreatic

What you can do

• Add the WikiProject Volcanoes message box {{Volcano}} to talk pages of articles within the scope of this project, including appropriate assessments if needed.
• Ensure that all mountains and islands which are volcanoes are properly noted as such in the article text, with proper references.
• Assess all articles within the scope of the project.
• 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.
  Use the {{convert}} template to ensure accurate conversion of elevations, distances, areas, and volumes.
• Expand volcano articles which are stubs, especially by adding photos and (most importantly) proper references.
• Expand the list of volcanoes, it is underpopulated in many areas.
• Bring more volcano articles to Good Article and Featured Article status, including Mount Baker, Mount Vesuvius, Mount Garibaldi, Mount Pelee, Mount Meager, Mount Cayley, Anahim hotspot, Mount Rainier and Mount Edziza volcanic complex.
• Help improve articles related to Hawaiian and Canadian volcanism by joining the Hawaiian and Canadian workgroups.

Featured work

Featured articles: 1980 eruption of Mount St. Helens  • Amchitka  • Craters of the Moon National Monument and Preserve  • Eldfell  • Enceladus (moon)  • Geology of the Lassen volcanic area  • Io (moon)  • Loihi Seamount  • Mauna Loa  • Metacomet Ridge  • Mount Pinatubo  • Mount St. Helens  • Mount Tambora  • Nevado del Ruiz  • Surtsey  • Triton (moon)  • Volcanism on Io  • Volcano (South Park)  • Yellowstone National Park

Featured lists: List of volcanoes in Indonesia

Good articles: Amak Volcano  • Anahim hotspot  • Ben Nevis  • Bowie Seamount  • Cerro Azul (Chile volcano)  • Crater Lake  • Ferdinandea  • Gareloi Volcano  • Geyser  • Glacier Peak  • Hawaii hotspot  • Lake Toba  • Minoan eruption  • Mount Adams (Washington)  • Mount Edziza volcanic complex  • Mount Garibaldi  • Mount Hood  • Mount Kenya  • Mount Rainier  • Mount Redoubt  • Roxy Ann Peak  • Rùm  • Mount Thielsen  • Mount Vesuvius  • Sakurajima  • Silverthrone Caldera  • Staffa  • Volcanic ash  • Weh Island  • Wells Gray-Clearwater volcanic field

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