Most earthquakes happen along the edges of Earth's big plates.
Aftershocks can follow an earthquake on and off for days or weeks.
Each year, there are about a million earthquakes around the world. But only about 100 of these cause serious damage.
The shaking of the ground is not what kills most victims of earthquakes. The main killers in earthquakes are falling buildings, fires, landslides, avalanches and tsunamis.