What Is A Volcano?

What is a Volcano?

A volcano is a landform (usually a mountain) where molten rock erupts through the surface of the planet.

In simple terms a volcano is a mountain that opens downward to a pool of molten rock (magma) below the surface of the earth. It is a hole in the Earth from which molten rock and gas erupt.

Did you know?

The name "volcano" has its origin from the name of Vulcan, a god of fire in Roman mythology.

As pressure in the molten rock builds up it needs to escape somewhere. So it forces its way up “fissures” which are narrow cracks in the earths crust. Once the magma erupts through the earth’s surface it’s called lava.

What is the difference between lava and Magma?

Magma is liquid rock inside a volcano.

Lava is liquid rock (magma) that flows out of a volcano. Fresh lava ranges from 1,300° to 2,200° F (700° to 1,200° C) in temperature and glows red hot to white hot as it flows.

What causes volcanoes to erupt?

The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move.

Between the Earth's crust and the mantle is a substance called magma which is made of rock and gases.

When two plates collide, one section slides on top of the other, the one beneath is pushed down. Magma is squeezed up between two plates.

The image below shows the different parts of a volcano.

Definitions

Magma - Molten rock beneath Earth's surface.

Parasitic Cone - A small cone-shaped volcano formed by an accumulation of volcanic debris.

Sill - A flat piece of rock formed when magma hardens in a crack in a volcano.

Vent - An opening in Earth's surface through which volcanic materials escape.

Flank - The side of a volcano.

Lava - Molten rock that erupts from a volcano that solidifies as it cools.

Crater - Mouth of a volcano - surrounds a volcanic vent.

Conduit - An underground passage magma travels through.

Summit - Highest point; apex

Throat - Entrance of a volcano. The part of the conduit that ejects lava and volcanic ash.

Ash - Fragments of lava or rock smaller than 2 mm in size that are blasted into the air by volcanic explosions.

Ash Cloud - A cloud of ash formed by volcanic explosions.

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