21 the earthquake statistics for the simulation with cells is depicted. The power law holds over nearly five orders of magnitude and the b-value is in excellent agreement with the expected value of 1.0. The simulation with cells gave a b-value of 1.07. The reason for the slight discrepancy is not very clear. It is possible that finite size effects are responsible.
More simulation runs with different parameters have to be performed.
Unfortunately, a big amount of computer effort is needed for this kind of simulations. For example the run with 64 times 64 cells took about 20 days on a Sparc 10 workstation. We always see a rich structure of aftershocks and if we turn to fig. However there are no precursor events in the case of the largest earthquake in fig. 20 at about time step 130000.