What is the difference between the focus and the epicentre?

The focus is where the rock actually broke, which is underground, sometimes tens of kilometres down. The epicentre is the point on the surface directly above it, which is usually where the shaking is strongest. This board draws the epicentre from the focus, so the two are always in line.

Why do earthquakes happen at plate boundaries?

Because that is where two plates are pushing, pulling or sliding past each other. The rock at the edges locks together, the pressure builds until it cannot hold, and it breaks: that is the earthquake, and the first board is the moment before it.

Is this the same crust as the volcano tool?

The same drawing, on purpose. The volcano, this and the mountains tool are three lessons about one picture, so a class sees the same ground three times rather than three different pictures of it.

Does it show the Richter scale?

No. Nothing here is scored or measured: the board names what happens and where. How big an earthquake was is a separate idea and it is not something this picture can show.

Earthquakes

Geography · Year 3–Year 6

Two plates, stuck and then slipping, with the words for what happens.

About the earthquakes

Two boards, and the second is the first one a moment later. The plates are pressed together and the rock is holding; press Next and the fault has slipped, with the focus where the rock broke, the epicentre on the surface above it, and the waves going out. An earthquake is a thing that happens, and one picture can only ever show the after.

Tap a part to name it. The words are the ones a KS2 unit asks for: plates, fault, focus, epicentre, waves, and the crust the plates are made of.

The focus and the epicentre are the pair to get right, and the board is built so it cannot get them wrong: the epicentre is drawn straight above the focus because that is what the word means, from the same number, with a line between them.

It is a schematic rather than a map of the real plate boundaries. What a class is being taught is what happens at one boundary, and a world map of the boundaries is a different lesson and another dataset to get right.

The fault is drawn on a slant, which is true of most real faults and is also the only arrangement that fits: drawn vertical, the fault, the focus and the epicentre sit on one line and a class could not tap one without hitting another.

Nothing is scored and nothing collapses. The two houses on the surface lean a little on the second board, which is what says the shaking reached them; a tool that drew a collapsed house would be a different conversation with a class.

How to use it on your whiteboard

1Tap a part to name it and see what it is.
2Tap Next to work round the board, and again to let the plates slip.
3Tap Show all to put every label up at once.
4Tap Hide to take them off and ask the class again.

Questions

What is the difference between the focus and the epicentre?: The focus is where the rock actually broke, which is underground, sometimes tens of kilometres down. The epicentre is the point on the surface directly above it, which is usually where the shaking is strongest. This board draws the epicentre from the focus, so the two are always in line.
Why do earthquakes happen at plate boundaries?: Because that is where two plates are pushing, pulling or sliding past each other. The rock at the edges locks together, the pressure builds until it cannot hold, and it breaks: that is the earthquake, and the first board is the moment before it.
Is this the same crust as the volcano tool?: The same drawing, on purpose. The volcano, this and the mountains tool are three lessons about one picture, so a class sees the same ground three times rather than three different pictures of it.
Does it show the Richter scale?: No. Nothing here is scored or measured: the board names what happens and where. How big an earthquake was is a separate idea and it is not something this picture can show.