  We introduce a new model for an earthquake fault system that is composed of
non-interacting simple lattice models with different levels of damage denoted
by $q$. The undamaged lattice models ($q=0$) have Gutenberg-Richter scaling
with a cumulative exponent $\beta=1/2$, whereas the damaged models do not have
well defined scaling. However, if we consider the "fault system" consisting of
all models, damaged and undamaged, we get excellent scaling with the exponent
depending on the relative frequency with which faults with a particular amount
of damage occur in the fault system. This paradigm combines the idea that
Gutenberg-Richter scaling is associated with an underlying critical point with
the notion that the structure of a fault system also affects the statistical
distribution of earthquakes. In addition, it provides a framework in which the
variation, from one tectonic region to another, of the scaling exponent, or
$b$-value, can be understood.
