Aftershocks in a frictional earthquake model
  Inspired by spring-block models, we elaborate a "minimal" physical model of earthquakes which reproduces two main empirical seismological laws, the Gutenberg-Richter law and the Omori aftershock law. Our new point is to demonstrate that the simultaneous incorporation of ageing of contacts in the sliding interface and of elasticity of the sliding plates constitute the minimal ingredients to account for both laws within the same frictional model. 
O.M. Braun, E. Tosatti
cond-mat.stat-mech cond-mat.soft