Within the context of self-organized critical systems, Olami et al, (OFC) (
1992) proposed a spring-block earthquake model. This model is non-conservat
ive and reproduces some seismic properties such as the Gutenberg-Richter la
w for the size distribution of earthquakes. In this paper we study further
seismic properties of the OFC model and we find the stair-shaped curves of
the cumulative seismicity, We also find that in the long term these curves
have a characteristic straight-line envelope of constant slope that works a
s an attractor of the cumulative seismicity, and that these slopes depend o
n the system size and cannot be arbitrarily large, Finally, we report that
in the OFC model the recurrence time distribution for large events follows
a log-normal behaviour for some non-conservation levels.