VOLCANOES Volcanoes I What is a Volcano A

VOLCANOES!

Volcanoes! I. What is a Volcano? A volcano is any opening in the Earth’s crust where magma, ash and gas are able to reach the surface Volcanoes may have more than one opening which are called vents The main vent is known as the crater

Volcanoes! I. What is a Volcano? Far below the crater is the magma chamber Magma rises from the magma chamber, through a conduit, into the throat of the volcano, until it reaches the crater

Volcanoes! 1. Large Magma Chamber 2. Bedrock 3. Conduit (pipe) 4. Base 5. Sill 6. Dike 7. Layers of Ash Emitted by the Volcano 8. Flank 9. Layers of lava emitted by the Volcano 10. Throat 11. Parasitic Cone 12. Lava Flow 13. Vent 14. Crater 15. Ash Cloud

Volcanoes! II. What Causes Volcanoes? Volcanoes are caused by one of three things: 1. Convergent tectonic plates, usually at a continental-oceanic plate subduction zone 2. Divergent tectonic plates, usually at a mid- oceanic ridge 3. Mantle plumes a. k. a. “hot spots”

Volcanoes! III. Three Major Types of Volcanoes 1. Shield Volcano • Broad with gentle slope similar to a shield • Produced by low-viscosity lava flows • Mild eruptions • More common in oceanic than continental settings

Volcanoes! Mauna Kea in Hawaii

Volcanoes! III. Three Major Types of Volcanoes 2. Composite. Volcano (Stratovolcano) • Tall with steeper slopes similar to a cone • Produced by high-viscosity lava flows • Explosive eruptions of alternating layers of ash, cinders and lava • More common in subduction zones

Volcanoes! Mount Fuji in Japan

Volcanoes! Mount Mayon in Phillipines

Volcanoes! III. Three Major Types of Volcanoes 3. Cinder Cone • Small with steepest slopes • Produced by explosive lava flows • Violent eruptions • Commonly found around shield or composite volcanoes

Volcanoes! Sunset Crater in Arizona

Volcanoes! Capulin Volcano in New Mexico