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What causes a volcano erupt?


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

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


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


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 ...

What makes a volcano erupt? | Reference.com


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.

How Do Scientists Know a Volcano Is About to Erupt? - Live Science


Oct 25, 2010 ... Mount Merapi is expected to erupt at any moment, and Indonesian officials ... " Rising magma causes solid rock to break, sending earthquake ...

Facts about Volcanoes for Kids - Primary Homework Help


We currently know of 80 or more which are under the oceans. ... volcano What causes volcanoes to erupt? The Earth's crust is made up of huge slabs called ...

Why do volcanoes erupt? What creates eruptions? - eSchooltoday


... forces molten matter to be expelled out to the surface, causing a volcanic eruption. ... Did you know? ... The mantle is made up of molten material and gases.

Volcanoes - Weather Wiz Kids weather information for kids


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

What Causes A Volcanic Eruption? | IFLScience


Jan 6, 2016 ... What causes the world's explosive volcanic eruptions, like the 1980s ... gas bubbles form from the magma in a process known as vesiculation, ...

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


Jan 5, 2015 ... The eruption of a volcano can be one of the planet's most destructive events — spewing huge amounts ... How It Happens | Man-Made Quakes.