The main objective of WP3 is better understood by splitting it into three components that aim to:

- Use different methodologies and tools of network theory to facilitate the analysis of vulnerability, risk, and resilience of physical networks subjected to severe earthquakes.
- Synthesize the complexity of physical networks into graphical models (GMs)—i.e. a combinations of graph, decision, and probability models—that enable relevant analysis without falling into the large complexity of physical networks.
- Develop a methodology to model and evaluate the interdependencies of the selected physical networks within these graphical networks models, investigate cascading effects, and evaluate global resilience at the network level.

The simulation of high resolution large-scale models of the aforementioned DNS is forbidding in terms of computational time, and the conceptual and computational leap on how to scale these physical models up as components of other more complex system (e.g., the city) is a non-obvious step. Indeed, it is not trivial how to effectively use these physical models to investigate certain systems of systems features, such as interdependency and cascading effects, and graphical models (GMs) appear as a more appropriate tool. Therefore, a hypothesis of WP3 is that network theory in conjunction with probability theory may help characterize in a different format these physical systems and deal with them in a more amenable way for integrated earthquake vulnerability, risk, and resilience analysis.