Volcanoes

​​How Volcanoes Form

By: Ye Na Kim & Yelim Maing 7A   There are two kinds of volcanoes:
 * 1) Volcanoes erupt to form lava and ash deposits, it piled up lava or ash around the vent of small volcanoes and after many eruptions it form big volcanoes that is constructed of the ash and lava products of these eruptions. (mostly occur where two plates meet
 * Land volcano: formed when two plate boundaries slide under each another
 * Underwater volcano: formed when two land plates slide away from each other.

 There are three main types of volcanoes  Volcanoes erupt to form lava and ash deposits, it piled up lava or ash around the vent of small volcanoes and after many eruptions it form big volcanoes that is constructed of the ash and lava products of these eruptions.
 * Shield volcanoes: form by layers of lava flows, they are completely basalt.
 * Composite volcanoes: form by alternating layers of ash and lava
 * Cinder volcanoes: are composed of small lava fragments and form slopes of 30 to 40 degrees. It formed when if flow huge amounts of magma. And it is most powerful volcanoes.

There are three ways that volcanoes form. It is Subduction Zone volcanoes, Mid-ocean rift volcanoes, and hot spot volcanoes. Subduction Zone Volcanoes: form at the boundaries of two plates. Is the most violent and destructive of the three volcanic types. Mid-ocean rift Volcanoes: Form where two oceanic plates are spreading apart. A mid-ocean rift volcano is the world’s longest continuous mountain chain. Hot Spot volcanoes: usually found under oceanic crust

Where Volcanoes Form Most of the volcanoes are formed along a belt, called the Ring of Fire (The Pacific Ring of Fire is an area of frequent volcanic eruptions Pacific Ocean. The Ring of Fire has 452 volcanoes and is has over 50% of the world's active and dormant volcanoes. Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.) Volcanoes also form where the Earth’s crust are broken into plates that is like a jigsaw puzzle. There are 16 major plates. The rigid plates float on a softer layer of rock in the Earth’s mantle. As the plates move about they push together or pull apart.

· Rift volcanoes form where the plates are moving away from each other. They fill the separations with lava flows, creating new sea floor and mountain ridges beneath the waves. · Subduction volcanoes form where the plates collide and slide over each other. They create ridges and peaks. About 1,000 live subduction volcanoes occur in this ring of fire, and in any one-year, approximately 40 will be in some be ready to eruption. The Ring of Fire is composed of stratovolcanoes, which normally occur in chains, and account for over 95% of the world's active volcanoes. · Hot spot volcanoes don't follow to the rule of volcanoes occurring along plate margins. There are constant zones of magma within the earth in some places beneath the plates. The magma pierces through the plate. As time passes and the plates move, new volcanoes appear, and the extinct volcanoes are carried away with the drift of the plates. The common forms of hot spot volcanoes are shield volcanoes, like Mauna Loa of the Hawaiian Islands.
 * Other Kinds of Volcanoes and where they Form**

Work Cited [] [] <span style="font-family: Georgia,serif; font-size: 90%;">[] []

http://images.google.com/imgres?imgurl=http://volcano.oregonstate.edu/vwdocs/vwlessons/lessons/Volcanoes/Picture10.jpg&imgrefurl=http://volcano.oregonstate.edu/vwdocs/vwlessons/lessons/Volcanoes/Volcanoes10.html&usg=__fEAI6TtDYNz2rgjYrh4n21c7X4w=&h=288&w=343&sz=24&hl=en&start=2&um=1&itbs=1&tbnid=3QjmN4HJXsTlMM:&tbnh=101&tbnw=120&prev=/images%3Fq%3DHow%2Bvolcanoes%2Bform%26hl%3Den%26safe%3Dactive%26sa%3DN%26um%3D1.

[] [] []