Magma rising through cracks and weaknesses on the earths crust. When this pressure is released, eg through the movement of plates, it casues magma to rise to the surface forming a volcano.
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Describe the global distribution of a volcano
Mainly along plate boundaries, Destructive (convergent) and Constructive (divergent) and also in the Ring of Fire (Pacific Ocean). Can occur in the middle of plates, this is called a hotspot.
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Name 4 Primary Hazards of a volcano?
Pyroclastic flows, Lava Flows, Volcanic Gases and Tephra
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What is a Pyroclastic Flow?
The frothing of magma at the vent produces bubbles that burst producing poisenos gases as well as hot ash. Clouds form these gases and materials are most lethal when they roll down the sice of a volcano
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What is a Lava Flow?
Flows of molten rock, often fast moving and lethal
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What are Volcanic Gases?
Mixed gases emitted during explosive eruptions. The CO2 is particularly dangerous.
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What is Tephra?
Rock fragments ejected into the atmosphere. The accumilation of tephra on roofs can cause roof fires and buildings to collapse.
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Name 2 secondary hazards of a Volcano?
Lahars and Jokulhaups
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What are Lahars?
Mudflows created by the combination of heavy rain on slopes covered by fine volcanic material.
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What is a Jokulhaups?
A catastrophic flood due to an eruption underneath a glacier.
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Other cards in this set
Card 2
Front
Describe the global distribution of a volcano
Back
Mainly along plate boundaries, Destructive (convergent) and Constructive (divergent) and also in the Ring of Fire (Pacific Ocean). Can occur in the middle of plates, this is called a hotspot.
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