1. Earthquakes usually happen on the edge of tectonic plates.
Earthquakes are more common in certain countries due them being on the edge of tectonic plates.
Tectonic plates are the outer layer of the Earth.
They are made of rock and are constantly moving.
2. Earthquakes occur when the plates get stuck but keep trying to move!
The tectonic plates are constantly moving but sometimes they get stuck.
When they get stuck, pressure builds up and the plates will suddenly move.
This causes an earthquake!
3. Before an earthquake foreshocks might occur.
Foreshocks can sometimes occur before a big earthquake.
It can be one or more small earthquakes which happen in the lead up to a bigger one, which is known as the main shock.
Scientists can often use these to predict big earthquakes.
4. After an earthquake aftershocks are likely to happen.
After a big earthquake, aftershocks will often happen.
An aftershock is one or more small earthquakes after the main one has occurred.
This is because of the Earth’s crust adjusting to the effect of the main earthquake.
They can be very dangerous as buildings might already have damage to them from the large earthquake and so it can often cause them to fall.
5. The shockwaves that travel through the ground are called seismic waves.
The shockwaves that travel through the ground are called seismic waves.
They are very strong at the centre of the earthquake.
The waves travel to the surface and this is when the ground shakes and destruction happens.
6. Scientists use the Moment Magnitude scale to measure how strong an earthquake is.
Scientists use something called the Moment Magnitude scale to measure how strong an earthquake is.
