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Volcano

en.wikipedia.org/wiki/Volcano

A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava ... Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. ...

What causes a volcano to erupt and how do scientists predict ...

www.scientificamerican.com/article/what-causes-a-volcano-to/

Nov 29, 1999 ... When a part of the earth's upper mantle or lower crust melts, magma forms. A volcano is essentially an opening or a vent through which this ...

What causes a volcano erupt?

www.vtaide.com/png/George/volcanoes.htm

A volcano begins as melted rock (magma) which rises from deep inside the earth toward the surface. As the gas-filled magma rises ...

BBC - GCSE Bitesize: Key facts

www.bbc.co.uk/schools/gcsebitesize/geography/natural_hazards/volcanoes_rev1.shtml

Volcanoes form when magma reaches the Earth's surface, causing eruptions of lava and ash. They occur at destructive (compressional) and constructive ...

What Causes Volcanoes? Why do Volcanoes Erupt? - WorldAtlas.com

www.worldatlas.com/articles/what-causes-volcanoes-why-do-volcanoes-erupt-where-are-volcanoes-found.html

Jun 30, 2016 ... A volcano is a geological feature of the earth where an opening allows magma to escape from the mantle of the planet.

www.ask.com/youtube?q=What Causes A Volcano Eruption&v=ShOFQ2h2fws
Jun 19, 2014 ... Volcanoes form when magma from the earth's interior is able to make its way to the surface, via a vent. This is usually associated with plate ...

What causes Volcanoes? - Geoscience Australia

www.ga.gov.au/scientific-topics/hazards/volcano/basics/causes

Where plates move away from each other at spreading or divergent plate margins, volcanic eruptions are gentle extrusions of basaltic lava. Most of these occur ...

Volcanic Eruptions: What Causes Volcanoes to Erupt - Buzzle

www.buzzle.com/articles/volcanic-eruptions-what-causes-volcanoes-to-erupt.html

Aug 5, 2016 ... ... an enormous volcanic eruption. But, have you ever wondered what causes a volcano to erupt? If you have, this article has the answer for you.

How Do Volcanoes Erupt? - Universe Today

www.universetoday.com/31124/how-volcanoes-erupt/

May 26, 2016 ... Volcanic eruptions are driven by a combination of mechanisms, which include pressure and heat in the Earth's mantle, as well as tectonic ...

Volcanoes - Weather Wiz Kids weather information for kids

www.weatherwizkids.com/weather-volcano.htm

Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Volcano eruptions have been known to knock down ...

Answer
Several factors trigger volcanic eruptions, including the buoyancy of magma, a build-up of pressure from the gases in the magma and an injection of new magma into a full magma chamber.
When a part of the earth's upper mantle or lower crust melts, magma forms. A volcano is essentially an opening or a vent through which this magma and the dissolved gases it contains are discharged.
More Info

What Causes A Volcanic Eruption? | IFLScience

www.iflscience.com

Jan 6, 2016 ... A team of volcanologists led by the University of Liverpool have released a perhaps controversial Nature study on the causes of volcanic ...

What causes volcanic eruptions? | Reference.com

www.reference.com

Volcanic eruptions occur when magma builds up beneath the Earth's crust and forces its way to the surface. Natural vents in the crust allow magma passage to ...

Why are there volcanoes? Why do they erupt? | Volcano World ...

volcano.oregonstate.edu

Volcanoes erupt because of density and pressure. The lower density of the magma relative to the surrounding rocks causes it to rise (like air bubbles in syrup).