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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).

USGS FAQs - Volcanoes General - How Do Volcanoes Erupt?


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 ...

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.

How do cinder-cone volcanoes erupt? | Reference.com


Cinder-cone volcanoes, properly called scoria volcanoes, erupt when expanding gas bubbles drive lava to the volcano's surface. Because of this pressure, the ...

Cinder cone - Wikipedia


A cinder cone or scoria cone is a steep conical hill of loose pyroclastic fragments, such as either volcanic clinkers, cinders, volcanic ash, or scoria that has been built around a volcanic vent. Th...

Cinder Cone Volcanoes - Extreme Science


Eruptions from cinder cones are pretty small potatoes, as far as volcanic eruptions go. They tend to be small, hill-sized volcanoes that range in height from tens ...

How often do volcanoes erupt? | Volcano World | Oregon State ...


Eruptions. Well that depends on the volcano . Some volcanoes erupt very often ( and some like Kilauea almost never stop). On the other hand, some volcanoes ...

Types of volcanic eruptions - Wikipedia


Several types of volcanic eruptions—during which lava, tephra and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by ...

What happens when a volcano erupts? | Reference.com


Volcanoes erupt to release pressure built up in the magma chamber by expelling the magma as lava. Along with lava, a volcanic eruption releases ash and ...

Popular Q&A
Q: Why does a volcano erupt? - Quora
A: First you need to know a little bit about plate tectonics and I'm going to assume some knowledge anyway so you should do some reading on that and ask more ... Read More »
Source: www.quora.com
Q: Do volcanoes erupt only once? - Quora
A: The majority of volcanoes are the focus for magma flow and thus erupt multiple times. There are many examples, eg, Kiluaea, Mt St Helens, ... Read More »
Source: www.quora.com
Q: Why does volcanoes occur at mountainous regions? - Quora
A: It might seem so, but actually the opposite is the real reason, most volcanoes actually form the mountains. Age long eruptions gather at one point forms the ... Read More »
Source: www.quora.com
Q: What are possible causes for a volcano to erupt - Quora
A: Rising pressure in the earth's crust, especially in plate collision zones. Krakatoa was a good ... How / why does pressure build in a volcano causing an ex... Read More »
Source: www.quora.com
Q: Is the volcanic eruption in Pompeii (2014) realistic? - Quora
A: I haven't gone to see the movie, I could tell from the trailer I would make me beat my ... the movie, I could tell from the trailer I would make me beat my... Read More »
Source: www.quora.com