Analysis of the global maritime transportation system as a layered network

We model the global maritime transportation system as a multilayer network of sea routes and land routes that work together to deliver cargo on a global scale. The nodes of this network represent seaports and maritime chokepoints, and the arcs represent route segments at sea or on land, respectively. We construct our network using free, publicly available data from online sources, and we reverse engineer the global demand for container cargo transport. We use this layered network to identify important nodes from a connectivity standpoint. We also develop a flow-based model that directs the aggregate movement of goods between ports on the shortest and/or cheapest available route, and uses re-routing strategies if a route segment becomes impassable for container ships. We use this model to assess the impact of the loss of one or more container ports or maritime chokepoints. Using the base case of no disruptions, we measure the amount of goods that have to be re-routed in case of each disruption and the corresponding "cost" of doing so. Collectively, these results present a novel view of the security of transportation supply and set the stage for future work examining the global resilience of maritime transport systems.