The barriers found on fault lines are usually regions in which a strong pinning force reduces the movement of the plates. However geologists cannot define the position of these barriers around the fault lines. Rundle et al . use a 'stochastic Griffith theory' to statistically calculate the distribution of barriers, and thus predict if it will arrest an earthquake or not. The Griffith theory of tensile fracture suggests that the growth of a crack in a material - which is what an earthquake is - is determined by factors such as surface energy, friction and elastic energy of the material. The crack only becomes bigger when the energy needed to separate the crack tip is greater than the energy released upon the growth of the total surface area. Their theory includes a term which represents an additional energy sink that arises from the barriers.

Computer simulations by Rundle et al. show a series of "earthquake cycles" - including foreshocks, a main shock and aftershocks - that are similar to what is observed in "real" earthquakes.