Abstract: Clarifying the risk evolutionary mechanism of critical infrastructures is vital to preventing risks and mitigating the huge losses they may induce. However, the situation is extremely complex due to its nature of multiple risks, multiple systems, and their dynamically evolving interdependency. Hence, this paper firstly investigates the complex interdependency scenarios, and analyzes the respective evolutionary mechanism of multiple risks and multiple systems. Based on the analysis, it constructs a system dynamics model to demonstrate the risk evolutionary behaviors in critical infrastructures, and designs three targeted simulation experiments. By setting different interdependent scenarios, the comprehensive evolutionary mechanism from major risk factors to the overall critical infrastructure systems can be identified. Simulation results show that the risk factors affecting the operation of critical infrastructures are dynamically evolving, and the relevant regulatory authorities should pay attention to different risk factors at different stages; the interactive effects of multiple risks will induce more losses to multiple systems, and higher interdependency between systems will expand the loss; the different strength of system interdependence will affect the recovery efficiency of risk response strategies. This paper provides important scientific evidence for the relevant regulatory authorities of critical infrastructures to intuitively identify the dynamic evolutionary path of multiple risks under complex interdependent scenarios, clarify the key risk factors affecting the operation of multiple systems, and formulate risk response strategies.

Key words: critical infrastructures, risk evolutionary mechanism, complex interdependent scenario, system dynamics