Large earthquakes as coordination problems

I've been experimenting with very simple models of fault systems, where small segments of the faults can rupture independently but can also trigger each other into rupture. One thing that has become clear is that, in my simple models, a precondition for having very large earthquakes is that the local conditions for large rupture have to be met basically everywhere along what will become the rupture. In this case, the precondition is essentially sufficient accumulation of slip potential (elastic strain or perhaps stress in a physical model, which mine is not).

When small earthquakes can spontaneously occur at any of the small segments along the fault system, releasing much of this slip potential, it is difficult (or rare) for all of the small segments to build enough slip potential to