Volcano Facts:
–What is a Volcano?
Volcanoes are holes in the Earth from which molten rock, gas and ash erupt. Magma is the name for molten rock mixed up with gas and sometimes gas bubbles, whilst it is still under the ground. Lava is the name for when it breaks through the Earth’s surface, and you probably know this already, but lava is seriously hot. When we talk about erupt it means to burst out in a rather dramatic way!
The Earth’s surface, called the crust, is made up of huge slabs called plates. They fit together like a jigsaw puzzle. When these plates move and crash against each other the one that slides underneath is pushed down and magma squeezes up between them and rises to the surface of the earth. This then makes bubbles of gas which can cause pressure to build up and eventually explode
–What causes Volcanoes?
Volcanoes happen when magma rises to the surface of the earth, which causes bubbles of gas to appear in it. This gas can cause pressure to build up in the mountain, and it eventually explodes. When the magma bursts out of the earth, it is called lava.
–How are Volcanoes Formed?
Way deep down in the Earth, in the Earth’s upper mantle, you’ll find magma, debris and gases. When magma works itself up through the Earth’s surface it erupts through a vent to create lava flows and ash deposits. It is one of nature’s unbelievable natural events.
–Why do Volcanoes Erupt?
The Earth’s crust is made up of huge slabs, and these are called plates. Think of them like a massive big jigsaw puzzle where the pieces all fit together. Sometimes these plates move. This causes friction. When there is friction then this causes earthquakes and volcanic eruptions of the plates. This theory is called plate tectonics.
Type of Volcano
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Shape
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Height
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Slope
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Cinder Cone, AKA Scoria Cone
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Symmetrical cone
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Up to 1,200 feet (370 meters)
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30-40 degrees
|
Shield
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Tall and broad
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Up to over 30,000 feet (9,000 meters)
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Roughly 10 degrees near the base and 5 degrees near the top
|
Composite, AKA Strato
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Tall, steep, and symmetrical
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Up to 8,000 feet (2,400 meters)
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Roughly 6 degrees near the base and roughly 30 degrees near the top
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Lava Dome
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Dome
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Up to 330 feet (100 meters)
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25-30 degrees
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