  Laboratory earthquakes exhibit characteristics of a low dimensional random
attractor with a dimension similar to that of natural slow earthquakes. A model
of stochastic differential equations based on rate and state-dependent friction
explains the laboratory observations. We study the transition from stable
sliding to stickslip events and find that aperiodic behavior can be explained
by small perturbations in the stress state. Friction's nonlinear nature
amplifies small scale perturbations, reducing the predictability of the
otherwise periodic macroscopic dynamics.
