Energy can build up when the Earths crustal plates move against one another, compressing and stretching the surface of our planet. Mining and the building of dams also leed to a build up of energy or weakening of rocks that have stored compressed energy.

When the energy is released suddenly a shockwave ripples through the Earth. The release point of the energy is the focus of the Earthquake, and the point on the surface directly above the focus is the epicentre.

Effects

Earthquakes have primary effects, such as the collapse of buildings, which are a direct and immediate consequence of the shock waves.

Secondary effects are those that occur shortly afterward, such as fires or even Tsunamis.

The tertiary effects are the more long term consequences for the people and places affected by the earthquake. This could be homelessness, famine, or outbreaks of disease.