Geography

Question 1

What are convection currents?

Answer 1

Convection currents are slow yet extremely powerful movements of volcanic rock in the mantle.

Question 2

What process do convection currents follow?

Answer 2

The magma is heated to 50000C in the mantle and rises to the crust where they cool and sink only to be heated again.

Question 3

Describe Oceanic crust

Answer 3

plate that is made up of more dense rock. It sinks easily due to its density and is constantly created at boundaries. It is ‘young/new rock’ and forms our ocean bed.

Question 4

Describe Continental crust

Answer 4

this is a plate that is made up of less dense rock. Because it is less dense it doesn’t sink. It is exceptionally old and makes up our land surfaces

Question 5

What is the subduction zone?

Answer 5

where one plate is forced downwards below another plate and grinds past it causing huge amounts of friction and heat.

Question 6

What is an ocean trench?

Answer 6

a particularly deep point of the ocean bed where the oceanic and continental crust have dragged each other downward.

Question 7

What are fold mountains?

Answer 7

large mountain ranges formed by the collision and ‘folding’ of two plates as they plates continually push into one another.

Question 8

How do tsunamis form

Answer 8

Tsunamis are usually triggered by earth quakes. The crust shifting is the primary effect; a knock-on(secondry) effect of this is the displacement of water above the moving crust this is the start of a tsunami. A normal wind-driven wve may have a length of 100m from crest to crest but a tsunami may be 200 km in length. The heights also greatly differ. 2m for a normal wave and 1m for a tsunami out at sea but it does gainheight and can reach up to 100s of feet

Question 9

What is a plate boundary?

Answer 9

where two very large crustal plates meet on the earth’s surface. Earthquakes and volcanoes happen here.

Question 10

How do tsunamis form?

Answer 10

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