The Process
Volcano Layers
Underneath of the earth there are many different layers. Each layer is a little different and serves a different purpose. The top layer that we see is called the earth's crust. Above the crust on a volcano you can see the volcano's core and the Tephra (ashes). Below the earths crust is a series of 16 Strata's. Strata's are plates and they float on top of the middle of the earth (the mantel). The mantel's temperature is so hot all of the rocks exist in a melted form. The rocks in between the middle and the crust are still solid, but moldable.
Pressure and Weakness Combined
Sometimes the earths crust becomes weak and the pressure under the middle layer of rocks becomes high. With the high pressure the rocks melt and are called magma. The pressure can become so great that it shoots the magma right out. The earths crust is already weak at the top and opens up. This opening becomes the core of the volcano. Once the magma spews out it is called lava. The lava will harden back up once it cools off. This can happen over and over and cause the volcano to get bigger and higher.
Tectonic Plates
Volcano's can also form when two of the earths tectonic plates (or Strata plates) get pushed together. One of the plates buckles under the other one. This creates a path for the magma to travel around. When the magma ends up close to the surface and is coupled with some pressure behind it, the magma is pushed through the core and it comes spewing out.
Hot Spots
Volcano's can also be formed in areas of the earth that have hot spots. Hawaii is one of those places. The temperature below the mantel layer is hotter than anywhere else. The heat makes the rock in the mantel level (the 16 plates) turn in to a bubbling liquid. It pushes this liquid (called magma) toward the top. All it takes is a little bit of pressure behind it and the magma comes spewing out.
If you enjoyed this article you can also build a volcano. Read how: Create Your Own Volcano: A 6th Grade Science Experiment
