Seismic gaps are places where scientists think that

The answer is Faults are storing elastic strain. To simplify, seismic gaps are places where scientist think that faults are keeping elastic strain. In addition, scientists think that stress on a fault constructs up to a critical point and is then unconstrained as an earthquake. The seismic gaps are areas in which no earthquakes have occurred over a long period of time and therefore are probable to be under a high volume of stress.