How are Volcanoes Formed
Posted on May 9, 2009 in Science/MechanicsVolcanoes are formed when their are cracks in the earth’s plates. The cracks up large areas in the earth where hot molten rock called lava can flow out of. One of the most popular places on earth that this happens is the Pacific Ring of Fire. 68% of all the Earth’s volcanoes are in the Pacific Ring of Fire.
Getting back to how do volcanoes form, the flowing lava builds layers onto itself and cools in the earths atmosphere. This is a long and slow process as the layers harden and build onto each other. If two plates collide and one plate is forced beneath the other, the enormous friction turns the first plate into hot molten rock and it rises up.
Hotspots are another way volcanoes form. A hot spot is basically a spot in the middle of one of the Earth’s plates and it does not move. The hot lava spews from the earth to the surface to form a volcano.
This is causes by a large amount of magma below the Earth’s surface. Once the magma is revealed through the volcano, the volcano can become extinct. Any volcano that have been inactive for more than 10,000 years is considered extinct.
Their are three main types of volcanoes: shield volcano, composite volcano and caldera volcano. Shield volcanoes have a flat dome-like shape created by layers of lava flowing over the surface and cooling down. Composite volcano’s are alternating layers of rocks and lava. Caldera volcano’s form when huge amounts of lava spews out of sub-surface magma chambers, and that is how volcanoes are formed.
