Earthquakes – Sudden or violent movements of the Earth's tectonic plates followed by a series of shocks
Earthquake = sudden plate movement
When the earth quakes (earthquake) the plates move (movement of the Earth's tectonic plates).
NOTE: See Mammoth Memory Tectonic Plates
There are three types of tectonic plate movements that can cause earthquakes at the plate margins (edges of the plates):
Conservative plate margin (sliding)
Constructive plate margin (moving apart)
Destructive plate margin (coming together)