Introduction ~ About Volcanoes

                Volcanoes are openings in the surface of the Earth where lava and gases can escape. Volcanoes are caused by the Earth's tectonic  plate boundaries The Earth's crust is its thinnest layer and is broken into plates. The plates lie above the hot mantle. Huge amounts of molten rock are in the mantle, causing the plates to move slowly. Many occur at the plate boundaries because the plates usually shift there. Scientists measure volcanoes by mapping. It helps to keep track of how fast the lava flow of a volcano is going towards an area where people live. Scientists map with a portable GPS (Global Positioning System) receivers. These devices receive the radio waves from GPS satellites to determine the position of the receiver on Earth's surface. Portable receivers record positions within 15 feet, which is well suited for lava flow maps. Scientists walk around the map flow's edges as near as possible, noting its characteristics and position. With GPS receivers the position is recorded by pushing a button and the data is recorded in the computerized memory of the device. The scientists download the coordinates and connect the dots. The result is an outline of the lava flow.


TYPES OF VOLCANOES
Subduction volcano - When the plates move toward each other and collide. It happens on destructive plate margins. One plate is more heavier than the other and is forced to subduct under the other, into the mantle, where it heats up and melts. It erupts under great pressure.The area where the two crusts are in contact is called the subduction zone.

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This is a subduction volcano. As you can see in the picture,these volcanoes are formed when the tectonic plates slide under one another and the volcanoe is formed and magma from one of the many layers of the earth rises which cause big or small eruptions.


Rift volcano- When the plates move apart from each other. Magma rises through the gap between the separating plates. Rift volcanoes erupt more gently, with lava oozing out of the small openings as opposed to a huge explosion with lava and ash filling the air.
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                                                                                                                This is a rift volcano


Hot Spot volcanoes-  Hot spot volcanoes are formed when plumes of magma force their way to/through the mantle. As the plates move, the volcano is carried away and becomes extinct.
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Volcanoes are formed all over the world. They are formed mostly near the plate boundaries because that is where the tectonic planes shift, causing things like volcanoes, earthquakes, and land movements which can lead to things like tsunamis, mudslides, or floods!

 
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