Abstract
Critical infrastructures display many of the characteristic properties of complex systems. They exhibit infrequent large failures events that often obey a power law distribution in their probability versus size. This power law behavior suggests that conventional risk analysis does not apply to these systems. It is thought that some of this behavior comes from different parts of the systems interacting with each other both in space and time. While these complex infrastructure systems can exhibit these characteristics on their own, in reality these individual infrastructure systems interact with each other in even more complicated ways. This interaction can lead to increased or decreased risk of failure in the individual systems. To investigate this, we couple two complex system models and investigate the effect of the coupling on the characteristic properties of the systems such as the probability distribution of events.