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46 Cards in this Set
- Front
- Back
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What is a pyroclastic flow?
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A fast (50-100mph) flow of gases and lava that move quickly down a volcano.
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Where does volcanic activity occur mostly?
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In the subduction zones or mid-oceanic ridge locations.
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What are the 2 types of volcanoes?
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1.) Strato Volcanoes
2.) Shield Volcanoes |
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What is a Strato Volcano?
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Very explosive with rocks, gases, and ash; Creates high cone, deep steep sides, and layered appearance.
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What is a caldera?
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The great, central depression that remains when a volcano explodes violently and the central portion of the volcano is destroyed.
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What is an example of a caldera?
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Crater Lake in Oregon or the San Francisco Peaks in Northern Arizona.
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What is a Lahar?
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An Indonesian term for a volcanic-created mudflow.
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What three processes combine to create a lahar?
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Mass Wasting + Fluvial + Tectonics
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At one time, what was going on at the San Francisco Peaks north of Flagstaff?
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The San Francisco Peaks was one huge volcano that erupted to the Northeast towards Sunset Crater.
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What is a Shield Volcano?
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Groups of fissures or tunnels that are active over a long period of time creating broad mountains.
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Where are shield volcanoes mostly located?
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In oceanic areas.
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How are shield volcanoes created?
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Hot Spots
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What happens when a lithospheric plate drifts slowly over a hot spot?
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A succession of shield volcanoes are formed.
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When a plate drifts over the plate, what happens?
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A chain of volcanic islands is formed.
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What is an example of a shield volcano?
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Hawaiian Islands
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What is a lava tube?
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A long, "worm-like" cave that is formed as molten lava flows through a tube formation of older, cold, hard lava.
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Where are there some examples of lava tubes?
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Found on the east and west sides of the San Francisco Peaks.
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Are lava tubes safe?
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Quite safe but you definitely need to take along at least 2 flashlights.
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How do you measure volcanic activity?
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Using the VEI: Volcanic Explosivity Index
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Are shield volcanoes safe?
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Enjoy the view unless your house is in the path of the lava flows, REMEMBER that these volcanoes are generally not explosive.
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What kind of volcano do you need to get out of the area right away?
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A composite volcano.
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Are we good at forcasting volcanic eruptions?
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We are getting much better.
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What is the US International Volcano Disaster Assistance Program?
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A cheap and efficient portable volcanic observatories.
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When was the US International Volcano Disaster Assistance Program founded and why?
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Founded after 1985 eruption of a volcano in Columbia which killed 23,000 people.
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What evacuation was the DAP in charge of?
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The evacuation of 56,000 people in the Philippines prior to the eruption of Mt. Penatubo.
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What is the measurement of a mega-volcano?
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VEI 8
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When and where was the last eruption of a mega-volcano?
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In Toba, Sumatra... 75,000 years ago.
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Compare the Toba volcano to Mount St. Helens.
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The Toba volcano had 10,000 times the explosive force of Mount St. Helens and changed life on Earth forever.
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Thousands of cubic miles of what went into the atmosphere during the Toba volcano.
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Ash
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2,500 miles away, how much ash coated the ground of the Toba volcano?
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14 inches of ash.
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What happened to the temperatures of Earth during the Toba volcano eruption?
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Temperatures plummeted globally by 21 degrees.
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What happened with the rain and plants during the Toba volcano eruption?
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The rain was poisonous by the gasses, black, and very acidic.
Three quarters of all plants in the Northern Hemisphere were killed. |
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What happened to humanity overall during and after the Toba volcano eruption?
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Humanity was pushed to the edge of extinction and the ENTIRE population forced down to just a couple of thousand of people.
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What is the current most dangerous Mega-volcano?
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Yellowstone National Park
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What would be the long-term effects of Yellowstone National Park erupting?
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Devastating! The thousand of cubic miles of ash that would shoot into the atmosphere could block out light from the sun, making global temperatures plummet.
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What would happen to crops and farmlands if Yellowstone National Park erupted?
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Harvests would disappear in hours because they would be coated in ash and there would be massive food shortages.
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What would happen globally if temperatures plummeted by 21 degrees like they did after the Toba eruption?
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It could truly be an extinction level event.
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What is faulting?
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The result of sudden yielding of the rock under unequal stresses: When one rock surface moves one way and the surface next to it moves another.
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What is a fault line?
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The division on the surface between the two different rock surfaces.
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What are the 2 types of faults?
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1.) Normal Fault
2.) Transcurrent Fault |
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What is a normal fault?
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The plane of slippage is steep or nearly vertical; One rock surface is raised or lowered in relation to the surface next to it.
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What is a fault scarp?
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A normal fault that results in a steep, clifflike feature.
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What is an example of a normal fault?
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Mongollon Rim
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What is a transcurrent fault?
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The movement in a transcurrent fault is not vertical but it's mostly horizontal; No scarp results.
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What is an example of a transcurrent fault?
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San Andreas Fault
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The San Andreas is a transcurrent fault between what 2 plates?
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The Pacific Plate and The North American Plate.
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