Related topics: volcano

Oral traditions and volcanic eruptions in Australia

In Australia, the onset of human occupation (about 65,000 years?) and dispersion across the continent are the subjects of intense debate and are critical to understanding global human migration routes. A lack of ceramic artifacts ...

Philippine volcano trembles more, spews lava half-mile high

A volcano near the Philippine capital spewed lava into the sky and trembled constantly Tuesday, possibly portending a bigger and more dangerous eruption, as tens of thousands of people fled villages darkened and blanketed ...

Formation of a huge underwater volcano offshore the Comoros

A new submarine volcano was formed off the island of Mayotte in the Indian Ocean in 2018. This was shown by an oceanographic campaign in May 2019. Now, an international team led by the scientist Simone Cesca from the German ...

Survey reveals low awareness of volcanic hazards in Australia

Heather Handley pointed out two large photos on her poster at AGU Fall Meeting last week: a bouncing kangaroo and a dreamy beach scene, two things commonly associated with Australia, where Handley is an associate professor ...

Why were tourists allowed on White Island?

The official death toll remains at five, and eight people are still missing, presumed to have died in yesterday's volcanic eruption at Whakaari/White Island.

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Volcano

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. The word volcano is derived from the name of Vulcano island off Sicily. In turn, it was named after Vulcan, the Roman god of fire.

Volcanoes are generally found where tectonic plates are diverging or converging. 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.

This text uses material from Wikipedia, licensed under CC BY-SA