# That Blue Square Thing - Geography Revision

## Unit 5 Markscheme - Plate Tectonics

WARNING! These pages are now very old. They were last updated in 2008 and the content applies to an old version of any geography syllabus currently active in the UK.
I've kept them here because there might be something useful for someone and the general marking principles aren't all that different. But be aware that it's old and out of date (the stuff on the Google Earth page in particular may not work at all)

Use this markscheme to check your own answers. If you're unsure then ask a teacher to give you a hand. With practice you should be able to mark your own work.

You might find it useful to look at the Standard GCSE Markscheme.

This explains a little more about level marked questions and gives an example. As examiners we're always interested to see useful case studies used in longer answers - this will often gain marks because it helps to explain the points you're making.

a) Explain how the Richter Scale works

Simply "measures earthquakes" worth 1 mark. Idea of measuring the shaking is worth a second mark. For the third mark you need to know that the scale isn't a simple sacale but every +1 magnitude is x10 shaking

b) Explain how earthquakes are caused.

Explain is the key word. The answer needs to go into the ideas of moving plates rubbing together (Level 1), pressure building up and being released (Level 2) and the reasons for the movement - i.e. showing an understanding of convection currents (Level 3). Being able to talk about actual places and plates will help the answer move up levels.

This is an example of an answer where you can learn a script. We see an awful lot of simple answers which just seem to say things like "the plates rub together and cause earthquakes". These get Level 1 marks. You can do better than that!

c) Describe the possible effects of a volcanic eruption on:
(i) a built up area
(ii) areas of fresh water

Two marks for each.

Built up areas might be covered by ash, destroyed by lava or mudflows or pyroclastic flows. People could be poisoned by gases. Fresh water could be filled with mud or ash and contaminated making it unfit for drinking. Fish or other water life could be harmed as well

d) Explain why volcanic eruptions are common along some types of plate margins.

At Level 1 you need to talk about pressure building up because of plate movement or plates moving apart and magma getting to the surface. To get into Level 2 you need to talk about at least one specific type of plate boundary - a constructive boundary is where two plates move apart; a destructive boundary is where an oceanic plate dips under a continental plate and pressure builds up. Both have volcanoes.

e) Suggest ways that the damage caused by earthquakes can be reduced

There are 3 marks and the question says "Suggest ways" so you don't need to go into huge detail here. Two points with some development should do.

Think about points like building design, building locations (not on sandy soils for example), materials, training/education and so on. Prediction will not work - the question is about earthquakes not volcanoes! We can't predict earthquakes.