A graphical version of this storyline is available. Earthquakes are movements in the Earth's crust. Shifting along a fault can be modeled by movements along a plane. The properties of faults in an area depend on the forces in that area.
Earthquakes occur in clusters.
Earthquakes are clustered in zones where the Earth's crust has been deformed. The locations of earthquakes are generally associated associated with major faults. The locations of earthquakes are often associated with topographic features. The locations of earthquakes vary in depth. The rate of earthquakes varies over time.