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Published byMilo McBride Modified over 9 years ago
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If you need help, look in your notes or your textbook!
Warm-Up Review Describe how the Andes Mountains in South America were formed. Use the words: Continental crust Oceanic crust Convergent boundary If you need help, look in your notes or your textbook!
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Vulcan- Roman God of Fire
Volcanoes Vulcan- Roman God of Fire
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What is a volcano? Volcano- Areas of Earth’s surface through which magma and volcanic gases pass
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What’s inside a volcano?
Magma Chamber- molten rock that feeds a volcano Vents- cracks in the crust What is the difference between magma and lava?
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Types of Volcanoes Shield volcano Cinder cone volcano
Composite volcano
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1. Shield Volcano Built from layers of lava Non-explosive eruptions
Not very steep, but can be big Example: Hawaiian Islands
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2. Cinder Cone Volcano Built from pyroclastic material
Moderately explosive, short eruptions Small in size, steep slopes Example: Mount Etna in Italy
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3. Composite Volcano Most common type
Explosive eruptions and lava flow Built from pyroclastic material AND lava Example: Many volcanoes within the Ring of Fire
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Factors Affecting Eruptions
Magma composition Viscous magma (maple syrup) has more violent eruptions that less viscous magma (more watery) Magma temperature Hotter magma flows easier so less violent eruptions Amount of dissolved gases The more dissolved gases, the more violent the eruptions
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What Erupts from a Volcano?
Blocky lava Lava can be thick or thin. Pahoehoe Aa Pillow lava
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What Erupts from a Volcano?
Pyroclastic material Rock fragments created by eruptions EXPLOSIVE Lapilli Volcanic bombs Volcanic blocks Volcanic ash
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How do volcanoes affect the Earth?
Flows and Fallouts hot ash can flow really quickly Knock down buildings Dam rivers (flooding/drought) Kill crops and livestock Climatic Changes Ash & Gases can block sunlight Drop average global temperature noticeably
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Craters, Calderas, and Lava Plateau
From explosions of material out of the vent and the collapse of material back into vent Caldera Much larger depression that forms when magma chamber empties and its roof collapses Lava Plateau Forms when lava erupts from long cracks, or fissures, and spreads out evenly (thousands of km)
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What causes volcanoes? Tectonic Plate Boundaries!!!
There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data. ~75% world’s active volcanoes in Ring of Fire
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How do volcanologists predict eruptions?
Measuring Small Quakes Before eruption, increase in number & intensity Measuring Slope Bulges may form with magma (tiltmeter) Measuring Volcanic Gases Outflow of volcanic gases Sulfur dioxide, carbon dioxide Measuring Temperature from Orbit Measure changes in temperature over time
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You should not be a Volcanologist if….
You don’t like hiking, backbacking, rockclimbing, etc. You are not interested in experiencing extreme temperatures and heights. If you don’t like to travel to incredible places and see breathtaking views of the world.
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