Volcanoes Flashcards
(27 cards)
Define Continental Drift.
the movement of continents and tectonic plates, which is driven by convection in the mantle.
Define Lithosphere.
The rigid outer layer of the earth, made up of the upper mantle and the crust.
Define Mid-ocean ridge.
A continuous mountain range found on the ocean floor.
Define Mountain belt.
A long chain of mountains.
Define Natural Disaster.
When a natural event causes great damage and loss of life.
Define Natural hazard.
When a natural event causes great damage and loss of life.
Define Ocean trench
A long, narrow depression on the ocean bed.
Define Ridge Push
When gravity causes the mid-ocean ridge to sink down and spread out.
Define Slab Pull
When the weight of the descending oceanic plate pulls the whole plate along and down.
Define Volcano
Volcanoes are opening or cracks in the lithosphere where magma can escape onto the surface.
Define Lava
Lava is molten rock that usually comes from the mantle.
Define Volcanic Bomb
Lumps of molten rock that solidify as the explode out of the vent.
Define Hot ash and dust.
Hot ash and dust are thrown into the atmosphere and eventually fall back to the Earth sometimes hundreds of Kilometres from the volcano.
Define Shield Volcano.
A volcano with gentle slopes. They form from runny lava which spreads far from its source.
Define Composite/Strato Volcano
Tall volcanos with steep sides and a symmetrical cone shape. They form from very thick sticky lava which wont flow easily so the lava builds in around the vent.
Define active volcano
Is erupting or has erupted recently and is likely to erupt again.
Define dormant volcano.
Is one that has not erupted in 10,000 years
Define extinct volcano.
Hasn’t erupted for the last 1000000 years and probably never erupt again.
Define Crater
A hallow, tunnel - shape space at eh top of a volcanic cone.
Define secondary cone
If the main vent is blocked the magma is forced to surface in another rout.
Define main vent
This is the channel through which magma travels to reach the Earth’s surface.
Define magma chamber
A store of molten rock a store of molten rock deep inside the earth.
Define Pyroclastic Flows
A dense, destructive mass of very hot ash, lava fragments, and gases ejected explosively from a volcano and typically flowing at great speed.
Define Lahars.
When the volcano erupts, the ash from the eruption mixes with water, and flows downhill, it quickly solidifies and sets like concrete
