Volcanoes
By: Jason Guild Victoria Kinney Meghan Mercier
Rationale
• Current event of the eruption of Mt. St. Helens • Part of NYS Earth Science curriculum
What is a Volcano?
• An opening in the earth’s crust through which lava and gases erupt.
Where do Volcanoes Occur?
• “Ring of Fire” • Plate Boundaries • Hot Spots
What Causes Volcanoes?
• Divergent Boundaries • Convergent Boundaries
1)Oceanic-Oceanic 2)Oceanic-Continental
• Hot Spots
Different Types of Volcanoes
• Shield Cone • Cinder-Cone • Composite
Shield Cone Volcano
• Non-explosive eruption (lava comes out slowly) • Gentle slopes • Mainly at hot spots • Example: Hawaii
Cinder Cone Volcano
• • • •
Explosive Eruptions Steep Slope Built from tephra Example: El Salvador
Composite Volcanoes
• Repeated nonexplosive and explosive eruptions • Built from alternating layers of tephra and lava • Moderate slopes • Example: Mt. St. Helens
Mount St. Helens 1980
• May 18th, 1980 • 57 deaths • Flattened 230 square miles of forest land
Before and After 1980
Current Mount St. Helens Eruptions
• Lava rising up underneath volcano • Increased earthquake activity • Releasing of its pressure through steam eruptions. • Live webcam of Mt. St. Helens
References
• http://www.fs.fed.us/gpnf/volcanocams/msh/
• www.google.com • www.volcano.und.edu