Movements within the Earth’s crust cause stress to build up at points of weakness and rocks to deform.
Stored energy builds up in the same way as energy builds up in the spring of a watch when it is wound.
When the stress finally exceeds the strength of the rock, the rock fractures along a fault, often at a zone of existing weakness within the rock. The stored energy that is suddenly released as an earthquake!
Intense vibrations, or seismic waves, spread out from the initial point of rupture, the focus, like ripples on a pond. These waves are what makes the ground shake and can travel large distances in all directions.
Near the focus, the waves can be very large, making them extremely destructive.
In ancient times earthquakes were thought to be caused by restless gods or giant creatures slumbering beneath the Earth.
Despite being nowhere near a plate tectonic boundary the UK experiences hundreds of small earthquakes each year.
An interactive map of UK earthquakes
An interactive map of the biggest and the deadliest earthquakes in the world
Using pieces of foam or card you can model the movement of tectonic plates in different kinds of faults and boundaries.