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CONTINENTAL divergence Ocean- Continent Convergence Ocean Divergence Ocean-Ocean Convergence.

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Presentation on theme: "CONTINENTAL divergence Ocean- Continent Convergence Ocean Divergence Ocean-Ocean Convergence."— Presentation transcript:

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2 CONTINENTAL divergence Ocean- Continent Convergence Ocean Divergence Ocean-Ocean Convergence

3 Major Volcanoes Around the World

4 “RING OF FIRE”:Area surrounding the pacific plate where the most volcanoes & earthquakes occur

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6  Viscosity  Chemistry of Magma  Gases within the magma  Water content of magma

7  Active Volcanoes: recent eruptions, active magma source  Mt. Etna, Italy  Dormant Volcanoes: no recent eruptions, but still has an active source of magma  Mt. St. Helens, USA  Extinct Volcanoes: no recent eruptions, no source of magma  Northwestern Hawaiian Islands

8  Viscosity- the resistance of lava to flow Ex: The more viscous the lava, the thicker and stickier the material & the harder it is to flow (honey vs. water) depends on the amount of silica the type of crust being melted determines the amount of silica!

9  Caldera: large crater shaped basin that forms when the top of a volcano collapses

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11  Hot Spot- random upwelling of magma NOT associated with convection in the mantle  create a special type of volcanism not associated with plate boundaries  Ex: Hawaii, Yellowstone & Iceland Kaui Molokai Hawaii Oahu Lanai Maui

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13 1. Cinder Cones: explosive eruptions, small but steep slopes, pyroclastics Cinder Cone

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15 2. Shield: non-explosive eruptions, fluid basaltic lava, gentle broad slopes

16 Volcano Types

17 3. Composite Cones/Stratovolcanoes: alternating between lava and pyroclastics, explosive and non-explosive eruptions, very steep/tall

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20  Depends on type of crust melted  Oceanic Crust- quiet, effusive eruptions  Volcano type- shield, fissure, mid-ocean ridges  Magma type- mafic & ultramafic  Continental Crust or ocean/cont. mixed- explosive eruptions, pyroclastic flows, calderas, aerial bombs  Volcano type- stratovolcanoes & cinder cones  Magma type- felsic

21  Pillow Basalts (underwater) http://www.youtube.com/watch?v=DdIUuUY0L9c  AA lava- jagged lava  Pahoehoe- ropey, smooth lava

22  searing superheated gas and volcanic ash & dust; very fast  Also called “Nuee Ardente” http://www.youtube.com/watch?v=-H_HZVY1tT4 Mt. St. Helens Eruption http://www.youtube.com/watch?v=WxlRpuTed6g Pyroclastic Flow

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24  Draw an exaggerated, cartoon form of a type of volcano  Cinder  Shield (Dome)  Composite  Write a 5-6 sentence summary about it’s “personality.” Must include type of eruption, type of lava, size/shape, and location.


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