World Map of Fault Lines

Fault lines are the lines that mark a boundary between two tectonic plates of the Earth's crust. Earthquakes usually take places along these fault lines, as two plates move in different directions and built up pressure is released as the plates slip suddenly.

Why do tectonic plates move like that? Well, the plates are part of the Earth's crust, which sits on top of the Earth's mantle which is semi-molten. Since the mantle is not as hard as the crust, the crust "floats" so to speak, or slips/slides.

One fault line well known to North Americans is the San Andreas fault, which runs up the westcoast of the USA and was the location of the San Francisco earthquake.

Below you can find a world map of fault lines that may help you with your reference.