Wednesday, December 17, 2014

Volcanoes by Scott

Definition: “A vent in the earth's crust through which lava, steam, ashes, etc., are expelled, either continuously or at irregular intervals.”
-       Facts:

§  The Ring of Fire, located in the Pacific Ocean, has over 75% of Earth’s volcanoes

§  Volcanoes are usually formed on tectonic plates
§  Mantle plumes are volcanoes formed by hot spots and are located away from the tectonic boundary
§  When a volcano erupts it creates great farming soil
-       Magma
o   Definition: molten material beneath or within the earth's crust, from which igneous rock is formed.
-       Lava
o   The molten, fluid rock that issues from a volcano or volcanic vent.
-       Types of volcanoes
o   There are three main types
o   Shield
§  A broad volcano built up from the repeated nonexplosive eruption of basalt to form a low dome or shield, usually having a large caldera at the summit
§  Tend to have Low Silica Levels
§  Low viscosity levels
§  Has both High and Low gas levels
They are not that explosive


o   Composite (Stratovolcano)
§   A large, steep volcano built up of alternating layers of lava and ash or cinders.
§  High Silica levels
§  Highly viscous
§  High gas levels
Very explosive


o   Cinder cone
§  A small, conical volcano built of ash and cinders.
§  Low silica levels
§  High gas levels
§  Fountain eruptions


-       Viscosity
o   Definition: the property of a fluid that resists the force tending to cause the fluid to flow.
Lava has uses for farming, but does it have any other uses? Can we somehow harness the power of a volcano to provide heating for homes?


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