Lesson objectives:

Knowledge:

All will understand how earthquakes are measured.

Most will explain how seismic waves travel and the damage they can cause.

Skills:

All will evaluate where earthquake damage is greatest and explain why

Some will research how the damage from earthquakes can be managed

Keywords for today's lesson:

Epicentre

Focus

Seismic

Seismograph

Richter scale

Who?What?When?Where?Why?How?

Let’s remind ourselves how earthquakes happen:

http://news.bbc.co.uk/nol/shared/spl/hi/in_depth/nature_guides/swf/earthquake_aug09_466.swf

Most earthquake damage happens near the epicentre

http://upload.wikimedia.org/wikipedia/commons/c/c9/Epicenter.gif

How are earthquakes measured?

http://upload.wikimedia.org/wikipedia/commons/0/0f/Kinemetrics_seismograph.jpg

• Complete the measuring earthquakes worksheet using the key words

Key Words

Magnitude

Seismometer

Energy

Richter ScaleImage: http://pixabay.com/p-156000/?no_redirect

http://pixabay.com/en/users/OpenClips/

How are earthquakes measured?

1234

65

987

10

Richter Scale

The largest earthquake ever recorded was in Chile. It measured 9.5 on the Richter Scale.

The Richter Scale

This measures the magnitude of a tremor (how powerful it is) using an instrument called a seismograph.

The Richter Scale is measured on a scale from 1 to 10. It is a logarithmic scale which means that a size ‘6’ on the Richter Scale is 10 times more powerful than a size ’5’ and 100 times more powerful than a size ‘4’.

The Richter Scale:0 - 1.9Can be detected only by a Seismograph

2 - 2.9Hanging objects (lampshade) may swing

3 - 3.9Comparable to the vibrations of a passing lorry

4 - 4.9May break windows or cause small objects in your home to fall

5 - 5.9Furniture moves, chunks of plaster may fall from the walls

6 - 6.9Damage is caused to well built structures and severe damage to poorly built structures

7 - 7.9Buildings are displaced from foundations and there are visible cracks in the earth

8 - 8.9Bridges are destroyed and few structures are left standing

9 and overNear total destruction and seismic waves are visible to the naked eye (don’t worry, this rarely happens!)

Where on the scale is it and explain your choice:

1. 2.

3. 4.

Explain in your books in your own words ...

What is the Richter Scale?

A. B.

1. Will the vibrations be greater at A, or B? Why?2. Will the damage be greater at A or at B? Why? 3. An earthquake can occur at any time of day. When might an earthquake do more harm? At 5am OR b) at 10.30am Explain your answer.

Earthquake Damage Task Image adapted from: http://openclipart.org/image/300px/svg_to_png/59173/sydney-skyline.png

Plenary: Match up the correct keyword with its meaning.

Earthquake the scale used to measure the severity of earthquakes

Conservative Margin an instrument to measure earthquakes.

Plate Boundaries a movement or tremor in the earths crust.

Destructive Margin where two plates move alongside each other.

Seismograph where two plates are destroyed as they push towards one another.

Richter Scale the centre point of the earthquake on the earths surface.

Epicentre a boundary between two plates.