Presentation on theme: "By Sally Johnson March 11, 2010 Science Project Volcanoes."— Presentation transcript:
By Sally Johnson March 11, 2010 Science Project Volcanoes
Shield Volcano A shield volcano is wide, gently-sloping mountain made of layers of lava formed by quiet eruptions. Some volcanoes have thin layers of lava pour out of a vent and harden at the top of the previous layers on the volcano.
Composite Volcano A composite volcano is a tall, cone shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials. Some examples of composite volcano are in Mount Fuji in Japan and Mount St. Helens in Washington state.
Cinder Cone A cinder cone is a steep, cone – shaped hill or mountain made of volcanic ash, cinders, and bombs piled up around a volcanoes opening. If a volcano’s lava is thick and stiff it may produce ash cinders and bombs. For example, Paricutin in Mexico erupted in 1943 in a farmers cornfield. It built up a cinder cone about 400 meters tall.
Caldera A caldera is a large hole at the top of a volcano formed when the roof of a volcanoes magma chamber collapses. When the mountain becomes a hollow shell it collapses inward. The hole is filled with the pieces of the volcano that fell in.
Hot Springs and Geysers A hot spring is a pool formed by ground water that has risen to the surface after being heated by a nearby body of magma. A geyser is a fountain of water and steam that builds up pressure underground and erupts at regular intervals.
Bonus Slide An island arc is a string of islands formed by the volcano’s along a deep ocean trench. Ring of fire is a major belt of volcano’s that rim the pacific ocean. A hot spot is an area where magma from deep with in the mantle melts. A Magma Chamber is a pocket beneath a volcano where magma collects. A Pipe is a long tube through which magma moves from the magma chamber to the earths surface. A vent is the opening through which molten rock and gas leave a volcano.