volcanoes. general volcano info. most of the thousands of volcanoes on earth are inactive. earth has...
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Volcanoes
General Volcano Info.• Most of the thousands of
volcanoes on earth are inactive.
• Earth has about 600 active volcanoes right now.
• The most active volcano on earth is Kilauea on the island of Hawaii.
Causes of Volcanoes
•1. Divergent Boundaries: Tectonic plates pull apart, lava oozes out.
•2. Convergent Boundaries: Two plates meet, the ocean plate dives under the continent plate. The melted material forms volcanoes. (Subduction)
•3. Hot Spots: Some areas of the mantle are hotter than others. Over these “hot spots” magma forces its way to the surface.
Types of Eruptions• 1. Explosive: Sometimes
called a loud eruption, these are explosive, violent eruptions.
• 2. Quiet: In a quiet eruption, lava quietly flows out of a volcano.
Types of Volcanoes• 1. Shield Volcano: A shield
volcano is formed by quiet eruptions of lava. Kilauea is a shield volcano.
• Gently sloping sides – Low Silica Lava – Not Explosive.
•2. Cinder Cone Volcano: A cinder cone volcano is an explosive volcano.
•Steep sides - High Silica Lava – Tephra (Ash & Lava) – Explosive – Lava Bombs.
•Composite or Strato Volcano: Some eruptions are quiet and some are explosive.
•Can be Lava or Tephra. – Medium steep sides – Layers of Lava & Tephra.
BrainPop
• http://www.brainpop.com/science/theearthsystem/volcanoes/zoom.weml
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