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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).

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 ...

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 ...

How It Happens | Volcanic Eruptions - Video - NYTimes.com

www.nytimes.com/video/science/100000003431211/how-it-happens-volcanic-eruptions.html

Jan 5, 2015 ... The eruption of a volcano can be one of the planet's most destructive events — spewing huge amounts of rock, gas and ash that can kill people.

Volcanoes - Weather Wiz Kids weather information for kids

www.weatherwizkids.com/weather-volcano.htm

An extinct volcano is one which has erupted thousands of years ago and there's no possibility of eruption. Why do volcanoes erupt? The Earth's crust is made up  ...

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 ...

www.ask.com/youtube?q=Why Do Volcanoes Erupt&v=-kQwudeT3ww
Jun 29, 2013 ... A quick and fun cartoon lesson about volcanoes. Great for teachers and students- hope you ... USGS - How do volcanos erupt? - Duration: 3:13.

BBC - GCSE Bitesize: Key facts

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

A secondary school revision resource for GCSE Geography covering key facts about volcanoes and volcanic eruptions.

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 ...

Explainer: Why volcanoes erupt - ABC News (Australian ...

www.abc.net.au/news/2015-08-06/volcanoes-explainer-why-they-erupt/6676400

Aug 5, 2015 ... Some people believe volcanic eruptions are caused by fate. Others believe a volcanic eruption is a sign that a mountain is upset because ...

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.
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Explainer: why volcanoes erupt - The Conversation

theconversation.com

Aug 4, 2015 ... What happens beneath the surface before a volcano erupts? ... Some people believe volcanic eruptions are caused by fate. .... for fewer children · What do the Clinton charities actually do and where does their money go?

Why do volcanoes erupt? What creates eruptions? - eSchooltoday

eschooltoday.com

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 ...

Why do volcanoes erupt? | Reference.com

www.reference.com

Hot melted rocks collect under the Earth's surface and when the pressure becomes too hard, the Earth's skin breaks, and a volcano erupts. The melted rock  ...