Quasiperiodic Events in an Earthquake Model

We introduce a modification of the Olami-Feder-Christensen earthquake model [ Phys. Rev. Lett. 68 1244 (1992)] in order to improve the resemblence with the Burridge-Knopoff mechanical model and with possible laboratory experiments. A constant and finite force continually drives the system, resulting in instantaneous relaxations. Dynamical disorder is added to the thresholds following a narrow distribution. We find quasiperiodic behavior in the avalanche time series with a period proportional to the degree of dissipation of the system. Periodicity is not as robust as criticality when the threshold force distribution widens, or when an increasing noise is introduced in the values of the dissipation.