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    Volcanoes are one of the worlds most interesting things. They are found in many different places around the world. Volcanic eruptions occur when, rock from the mantle melts, moves to the surface through the crust, and realize pent-up gasses. But, do you know why solid rock melts and then comes to the surface? Extremely high temperature and pressure, melts the rock and pushes the new lava/magma to the surface. The hot liquid material is called Magma when it is still underground, but when it reaches the surface it is then called Lava. Magma comes in many different forms, the different forms all make up a different type of Lava.

    Most volcanoes occur on plate boundaries. Plate Boundaries are places where the earth shifts and moves closer together, or farther apart. Colliding boundaries or Convergent boundaries are when one plate meats the other, and slides underneath it, this process is called Subduction. As the downward moving plate is forced deeper into the mantle, parts of it begin to melt, and form magma that rises to the surface, usually in explosive eruptions. These usually make cone shaped volcanoes, called Stratovolcanoes. Some examples would be Mt. St. Helen's in Washington State.

    Separating or Divergent boundaries move apart, and hot rock forces its way through to the surface. Most of these are found under oceans, creating long undersea rift zones that fill up with lava. Most of these volcanic eruptions are not very violent. They erupt with a smooth steady flow of lava, that creates gently sloping sides, also know as shield volcanoes. Hot spots can also be what causes shield volcanoes. When plates move over hot spots, volcanoes spring up and then often form island chains. The Hawaiian islands are a result.

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