  We investigate the nonlinear properties of a system introduced by Burridge
and Knopoff to model the dynamics of earthquakes. We find that a two-block
system in a completely homogeneous configuration presents a complex behavior
characterized by the presence of periodic, quasiperiodic and chaotic orbits. We
have found routes to chaos via two types of intermittencies and period doubling
bifurcations. The sensitivity of the evolution to different initial conditions
is quantified by calculating the largest Liapunov exponent. The dynamics of the
model is governed by nondifferentiable flows.
