1. Volcanoes These notes go on p. 11 of your inb!!!

2. Volcanic Settings (Plate Boundaries)
Ocean-Continent Convergence
Ocean-Ocean Convergence
CONTINENTAL divergence
Ocean Divergence

3. Major Volcanoes Around the World

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

5. Plate Tectonics and Magma Generation
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6. PARAMETERS OF VOLCANISM
Viscosity
Chemistry of Magma
Gases within the magma
Water content of magma

7. Volcanic activity
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. TERMS TO KNOW: 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. Terms to know:
Caldera: large crater shaped basin that forms when the top of a volcano collapses

10. Formation of Crater Lake
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11. Terms to know:
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

12. Tectonic Settings and Volcanic Activity
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13. 3 types of volcanic cones:
1. Cinder Cones: explosive eruptions, small but steep slopes, pyroclastics
Cinder Cone

14. Volcano Types
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15. 3 types of volcanic cones:
2. Shield: non-explosive eruptions, fluid basaltic lava, gentle broad slopes

16. Volcano Types
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17. 3 types of volcanic cones:
3. Composite Cones/Stratovolcanoes: alternating between lava and pyroclastics, explosive and non-explosive eruptions, very steep/tall

18. Volcano Types
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20. Volcanism at different plate boundaries

21. Mid-ocean ridges & oceanic hot spots
Effusive Eruption (non-violent): low viscosity, flows easily, gases escape easily
Magma Type: mafic (dark, dense seafloor)
Volcano Type: Shield Volcanoes
Lava Type: Pillow

22. C Basaltic Lava Types Pillow Basalts (underwater) AA lava- jagged lava
AA lava- jagged lava
Pahoehoe- ropey, smooth lava

23. Subduction boundaries
Mostly Explosive Eruption (violent): high viscosity, does not flow easily, gases trapped, hard to predict explosions
Magma Type: felsic & mafic
Volcano Type: Composite Cone (Stratovolcanoes) & cinder cones
Other Features: gas flows, calderas, aerial bombs

24. C
PYROCLASTIC FLOWS
Mt. St. Helens Eruption
Pyroclastic Flow
searing superheated gas and volcanic ash & dust; very fast
Also called
“Nuee Ardente”

25. Debris Avalanche and Eruption of Mount St. Helens, Washington
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26. Continental divergent boundary & Continental hot spots
Explosive Eruption (violent): high viscosity, does not flow easily, gases trapped, hard to predict explosions (always explosive!)
Magma Type: felsic or rhyolitic
Volcano Type: Composite Cone (Stratovolcanoes), cinder cones, dome complexes
Other Features: gas flows, calderas, aerial bombs, pyroclastic flows

27. Magma and Erupted Materials
Silica Content
Melting Temp.
Gas Content
Viscosity
Type of Eruption
Location
Least (~50%)
Basaltic Magma
Least
Least viscous
Rarely explosive
Highest
Rifts, oceanic hot spots
Rhyolitic Magma
Most (~70%)
Most
Most viscous
Usually explosive
Lowest
Continental hot spots
Andesitic Magma
Intermediate (~60%)
Intermediate
Sometimes explosive
Subduction boundaries

28. Volcano CarIcAtures
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.