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What's A Volcano?

History of Volcanic Activity

Potential Volcanic  Hazards

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Abstract

What's a Volcano?

A Volcano is an opening in the earth’s crust through which molten lava, ash and gases are ejected.

Source: AP

There are three types of volcanoes

Volcano Type	Size and Shape	Common Eruption Type
SHIELD VOLCANO	Gentle slopes;convex inward at top Few kilometers to 100 kilometers	Hawaiian eruptions, the calmest of them all, these volcanoes have a steady flow of lava that helps to build up and make these volcanoes so massive
STRATOVOLCANO	Steep upper slopes and gentle lower slopes; small summit crater Few kilometers to 15 kilometers	Highly explosive eruptions, these volcanoes are the most dangerous and are associated with causing massive destruction.
CINDER-CONE VOLCANO	Straight, steep slopes; large summit crater Less than 300 meters	Associated with a strombolian eruption, short-lived, explosive outbursts of pasty lava that is ejected into the air.

 Source of Graphic: http://www.geology.sdsu.edu/how_volcanoes_work/

Mauna Loa, located on the Big Island, is a great example of the enormous size that shield volcanoes can reach. Source: http://www.geology.sdsu.edu/how_volcanoes_work/

Mount Fuji is Japan's highest volcanoes and the world's most picturesque. It is a classic example of a Stratovolcano, and it's eruption could be very deadly for Japan. Source:http://www.geology.sdsu.edu/how_volcanoes_work/

              Sunset crater, located in Arizona, is one of the best examples of a cinder-cone volcano.                     Source: http://www.geology.sdsu.edu/how_volcanoes_work/

Volcanoes form along plate boundaries.

At a sub ducting plate boundary where two plates are converging into one another we can find stratovolcanoes being formed. Shield volcanoes are often associated with 'hot spots' and we also find magma where there is divergent plate boundaries.  Source: learn.arc.nasa.gov/ planets/3/drift.html

 The greatest example of volcanic activity on earth is called the 'Ring of Fire'.  It is located around the Pacific Plate boundary where plates are being sub ducted.

Source: http://usgs.gov