Complex dynamics in a one--block model for earthquakes
  A two-dimensional earthquake model that consists of a single block resting upon a slowly moving rough surface and connected by two springs to rigid supports is studied. Depending on the elastic anisotropy and the friction force three generic regimes are possible: i) pure creep; ii) pure stick-slip motion; and iii) a mixed regime. In all cases the long-time dynamics (fixed point, periodic orbit or chaos) is determined by the direction of the pulling velocity. The possible relevance of our findings to real faults is briefly discussed. 
Raul Montagne and G. L. Vasconcelos