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VOLCANOES!!!.

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Presentation on theme: "VOLCANOES!!!."— Presentation transcript:

1 VOLCANOES!!!

2 What is a Volcano? 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 is stored.

3 Eruption An eruption simply takes place when the magma stored in the reservoir reaches sufficient pressure to overcome the resistance of the rock that forms the roof of the magma chamber. Many things can cause this change in pressure to occur including earthquakes, plate movement in the Earth, melting glaciers, changes in tide and rainfall.

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6 Magma Chamber A magma chamber is a large underground pool of molten rock sitting underneath the Earth's crust. This magma is less dense than the surrounding mantle and so it seeps up to the surface through cracks and flaws in the crust. When it reaches the surface, it results in a volcanic eruption.

7 Ash Cloud Volcanic ash consists of small pieces of compressed rock and glass created during volcanic eruptions. These fragments are so small, and heated to such a temperature that they can be carried in the air for many miles.

8 Lava Lava is the rock expelled from a volcano during an eruption. When it first comes out, the lava can have a temperature higher than 700 degrees C. It then flows downhill from the eruption point until it cools and hardens

9 Main Vent A volcano's main vent is the point in the Earth's crust where hot magma has reached the surface. The familiar cone-shaped volcano builds up as ash, rock and lava ejected during eruptions fall back to Earth around the vent

10 Did you know? The name "volcano" has its origin from the name of Vulcan, a god of fire in Roman mythology.

11 The End


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