A smaller tremor or series of tremors occurring after an earthquake. Aftershocks result from static stress changes and ‘dynamic’ stresses (transient, oscillatory stress changes), that can weaken faults. Such dynamically weakened faults may fail after the seismic waves have passed, and might even cause earthquakes that would not otherwise have occurred (Kilb et al. (2003) Nature 408). See also Johnson et al. (2008) Nature 451. See Abe and Suzuki (2012) Acta Geophysica 60, 3, 547 on aftershocks in modern perspectives.