Tectonic hazards - powerpoint

The 97-2003 conversion of a powerpoint presentation I've made about plate tectonics. Please note that there are sounds on each transition to stop me from losing my concentration (because I'm weird like that) so if you don't like them, then mute it!

Also, on slides with lots of information, you'll notice there are lots of different colours. I didn't do this just for the sake of it, I did it because whenever there's lots of writing all of the same colour, I find it very hard to take it in without beginning to daydream (like I said, I'm weird) so I'm sorry if it's off-putting. xD

I hope it helps you to revise, and good luck in the exam! :)

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  • Created by: Amy
  • Created on: 16-06-11 11:49
Powerpoint Presentation 611 Kb

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Slide 1

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Tectonic hazards…read more

Slide 2

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Structure of the earth
· Inner core ­ solid iron
and nickel
· Outer core ­ liquid
iron and nickel
· Mantle ­ magma, 80%
of the earth's total
· Crust ­ hard outer
shell, 2 types ­
oceanic crust and
continental crust
Tectonic hazards…read more

Slide 3

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Structure of the earth
· The earth's crust is divided into a number of
tectonic plates. These float on the mantle and
move a few centimetres a year due to
convection currents in the magma which
move in circular motions. Earthquakes and
volcanoes occur where plates meet. At some
plate boundaries the plates are moving
towards each other, at other places the plates
are moving away from each other.
Tectonic hazards…read more

Slide 4

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Key words
· Earth's crust ­ the solid, outer layer of the Earth.
· Tectonic plates ­ large segments of the crust.
· Plate boundary ­ the boundary where two plates meet.
· Mantle ­ the layer of the Earth between the crust and the core.
· Magma ­ liquid rock below the Earth's surface in the mantle
· Convection currents ­ the circular currents of heat in the mantle.
Tectonic hazards…read more

Slide 5

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The types of crust
Continental Oceanic
Age 1500 million years + Under 200 million years
Weight Light Heavy
Thickness 30-70km 6-10km
Tectonic hazards…read more

Slide 6

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Destructive plate boundaries
The plates move together. If one plate is made from
oceanic crust and the other from continental crust, the
denser oceanic crust sinks under the lighter continental
crust (subduction). As the oceanic crust goes down, it
melts to form new magma, due to the heat of the mantle
and the friction between the two plates. The new magma
is lighter than the old magma and rises, reaching the
surface through cracks in the crust and erupting to form
volcanoes. When the magma rises offshore, volcanic
island arcs are formed. As the plates move against each
other, pressure builds up. A sudden movement of the
plate releases this pressure and the shockwaves cause
earthquakes at the surface.
Tectonic hazards…read more

Slide 7

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Slide 8

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Slide 9

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Slide 10

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