Whereas, plate boundaries are gaps that occur BETWEEN two distinct plates, faults are cracks, or fractures, that occur WITHIN a plate. Faults are most commonly found near plate boundaries, since this is where stress and pressure from plate movements is most concentrated. However, faults can also occur within the interior of plates themselves, hundreds or even thousands of miles away from any plate boundaries. This explains why there are sometimes smaller earthquakes in the interior of North America (such as in Oklahoma or Missouri). These are regions located near internal fractures, or faults, within the North American Plate.