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www.reference.com/article/volcanism-a416421f7f70bd4e

Volcanism is the eruption of magma to the surface of a planet. Molten rock wells up through a vent in the planet's mantle, spewing lava, gases and volcanic material into the surrounding area. Over time, this material hardens and accumulates, creating cone-shaped volcano...

www.reference.com/article/resources-recent-volcano-eruptions-797a0bd7b7906b16

VolcanoDiscovery.com is a website created and maintained by an international group of scientists and volcanologists that provides up-to-date information on current volcanic eruptions around the world. The Smithsonian's Global Volcanism Program also publishes regular eru...

www.reference.com/article/abundant-gas-released-during-volcanic-eruption-3d61cb7ec20fceba

While it may vary by volcano, the most abundant gas released during volcanic activity on average is water vapor. This is followed closely by carbon dioxide and sulfur oxide.

www.reference.com/article/volcanoes-erupt-62f6187dc3def972

Volcanic eruptions can either be effusive or explosive. An effusive volcanic eruption occurs when the lava pours out onto the ground from the volcano's vent. When the molten rock or magma is thin and runny, gases can easily escape and the lava flows freely and travels f...

www.reference.com/article/causes-volcanoes-erupt-18ca4578e393ea33

A volcanic eruption is caused by the injection of magma into a full magma chamber, the buoyancy of magma and the pressure exerted by the gases in the magma. The volcano simply acts as an opening through which magma and dissolved gases are discharged.

www.reference.com/article/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. The magma is in a reservoir like area under the surface and the pressure from the rocks causes the less dense magma...

www.reference.com/science/did-first-volcano-erupt-378d397f5e7f417b

The first volcano erupted approximately 4.5 billion years ago. This is when the earth first came into existence, and long before the first humans walked the earth, according to Scholastic, Inc.

www.reference.com/article/happens-volcano-erupts-b099f9c1fd7e5615

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 greenhouse gases such as sulfur dioxide and carbon dioxide.

www.reference.com/article/volcanoes-erupt-e8b4b9b0b15f4f66

Some volcanoes erupt often and some are inactive for long periods of time. The amount of time between volcanic eruptions depends on the volcano itself, according to the Department of Geosciences at Oregon State University.

www.reference.com/article/volcano-called-erupts-regularly-d9e37db6afee3795

A volcano that has recently erupted and may erupt again soon is categorized as an active volcano. Dormant and extinct are also categories of volcanoes.