Final answer:
Earthquakes are most likely to occur where stress has built up between plates. The motion along fault zones does not take place smoothly, and the plates can slide alongside each other or jam together. The longer the interval between earthquakes, the greater the stress and the more energy released when the surface finally moves.
Step-by-step explanation:
Earthquakes are most likely to occur where stress has built up between plates. The motion along fault zones does not take place smoothly, and the plates can slide alongside each other or jam together. When the stress between the plates is released in sudden slippages, earthquakes are generated. The longer the interval between earthquakes, the greater the stress and the more energy released when the surface finally moves.