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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 ...

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

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

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 ...

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

volcano.oregonstate.edu/why-are-there-volcanoes

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).

What makes a volcano erupt? | Reference.com

www.reference.com/science/volcano-erupt-4c02278a54b905b5

Volcanoes erupt due to pressure that the weight of the rocks puts on the magma and forces it to the surface out any available vent or exit provided to it.

USGS FAQs - Volcanoes General - How Do Volcanoes Erupt?

www2.usgs.gov/faq/categories/9819/2729

Some volcanic eruptions are explosive and other are not. How explosive an eruption is depends on how runny or sticky the magma is. If magma is thin and ...

www.ask.com/youtube?q=What Makes A Volcano Erupt&v=-kQwudeT3ww
Jun 29, 2013 ... A quick and fun cartoon lesson about volcanoes. Great for teachers and students- hope you guys enjoy! Be sure to subscribe if you like it, there ...

What Makes A Volcano Erupt? - Catalogs.com

www.catalogs.com/info/earth-science/what-makes-a-volcano-erupt.html

There are few geological events that are as dramatic as a volcanic eruption except maybe a hurricane, tornado or a tsunami. Each is drama.

Just Ask: What Makes Volcanoes Erupt? | PBS NewsHour

www.pbs.org/newshour/rundown/why-does-the-earth-have-volcanoes-and-what-makes-them-erupt/

Nov 30, 2010 ... It's time for our weekly Just Ask feature, where the experts tackle your questions on science and technology. John Eichelberger, a volcano ...

Why do volcanoes erupt? What creates eruptions? - eSchooltoday

eschooltoday.com/volcanoes/how-do-volcanoes-erupt.html

Find out what the earth make-up is, and how extreme pressure build up inside the earth forces molten matter to be expelled out to the surface, causing a volcanic ...

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, ... What is it exactly that makes molten rock rise from the Earth's interior and ...

Answers
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.