Do Now!

• Watch the live update link and describe what it is that you are seeing. Based upon what you

have studied so far can you see any links?

• http://www.iris.edu/seismon/

Key wordsFocus= the point within the earth where the seismic waves of an earthquake startEpicentre= the point above the focus on the earth’s surfaceSeismic waves= waves of energy in an earthquakeFriction = rub againstTension= energy that builds up

What happens in an earthquake?LO I can describe what happens in an

earthquakeSkill I can reflect on how to improve my work

Starter

Who can remember?List the types of plate boundaries that earthquakes occur on…

Activity 1 - What does it feel like when an earthquake occurs?

Watch the following clip of an actual earthquake…http://www.youtube.com/watch?v=JWtA-TxRO7A&feature=related

What would they be thinking

and feeling?

Activity 2 - What happens when an earthquake occurs?

• Watch the Boardworks animation (next 5 slides). Look carefully at what happens in an earthquake

• Take notes using the key words• Now describe in a paragraph what happens

when an earthquake occurs… EXTENSION - Make sure you use the following

words: Tension Focus Epicentre Seismic waves Friction

Epicentre and focus

Destructive plate boundary

Conservative plate boundary

The Richter scale can be used to measure the magnitude (power) of a tremor using an instrument called a seismograph.

How are earthquakes measured?

It is a logarithmic scale which means that a size ‘6’ earthquake on the Richter scale is 10 times larger than a size ‘5’ and 100 times larger than a size ‘4’.

How does a seismograph work?

The Mercalli scale rates an earthquake's magnitude based on observations of the damage it causes on a scale of 1 to 12.

The Mercalli Scale

Items shake from shelves: scale 5

Buildings collapse: scale 10

Where an earthquake happens?(Basic diagram to draw)

How do we measure earthquakes?

Plenary

• What number on the Richter Scale would you give the following earthquakes…

a b c

d e

TRUE OR FALSE???

A) Focus is the place on the surface of the earth directly above the epicentre

B) Seismic waves are waves of energy that travel out of the focus

C) Epicentre is the place in the earth’s crust where the tectonic plates move causing the earthquake

D) Tension stops the plates moving past each otherE) Friction stops the plates moving past each other