Scientists have found evidence of "earthquake clustering," in which a large earthquake is often followed by smaller aftershocks. However, studies in recent decades have found that large earthquakes can also trigger or be triggered by distant seismicity.

Some mechanisms, such as stress/strain changes may help explain correlations across larger geographical distances. For instance, a 1992 magnitude 7.3 earthquake in southern California produced a 0.11-millimeter strain change in the vicinity of the 1994 Northridge earthquake. There are also models to suggest that dynamic stresses/strains from one quake may travel along plate boundaries through the mantle to affect another area.