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A volcano is a land-form ( 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) bellow the surface of the earth. It is a hole in the Earth from which molten rock and gas erupt.
The earth crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. This plates sometimes move.
Between the earth crust and the mantel is a substance called magma which is made off rock and gasses.
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.
Driven by buoyancy and gas pressure the molten rock, which is lighter than the surrounding solid rock, forces its way upward and ultimately breaks through. Cloud of ash is formed by fragments of lava or rock smaller than 2 mm in size that are blasted into the air by volcanic explosions.
If the magma is thick and sticky , the gas can not escape, so it builds up and up until it explodes sending out huge clouds of burning gas and rock.
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 earths surface its called lava.
Eruption- process by which solid, liquid, and gaseous materials are ejected into the earth's atmosphere and onto the earth's surface by volcanic activity.
Volcanoes can have a serious effect on the lands and people around them when they erupt.
Lava Flow- An outpouring of lava into the land surface from a vent or fissure.
Lava is molten rock that spews from an erupting volcano. It is extremely hot. reaching temperatures as high as 1.300 to 2.000 degrees Fahrenheit.
In volcanic eruption, lava is in liquid form. When it solidifies, it forms igneous rock. However it can take quite a long time to cool, traveling great distances before becomes solid.
The name "volcano" has its origin from the name of Vulcan, a god of fire in Roman mythology.
There are three kinds of volcanoes