A system dynamics model for social vulnerability to natural disasters: Disaster risk assessment of an Australian city

The study of social vulnerability to natural disasters is appearing prominently in the recent academic and public discourse. However, there is a knowledge gap to forecast the evolution of social vulnerability in response to changes in its contributing factors. In the current state, most attempts have resulted in providing a snapshot of the social vulnerability at a given point in time. To sidestep this shortcoming, we introduce here a System Dynamics (SD) modelling approach that simulates the socio-economic and demographic characteristics of the population into the future. In doing so, a Causal Loop Diagram (CLD) is constructed to visualise the causal relationships between the interconnected variables associated with social vulnerability. Building on empirical data and using Analytic Hierarchy Process (AHP) method, the present paper turns the CLD to a Stock and Flow Diagram (SFD) to generate a social vulnerability index. This article then performs disaster risk assessment of an Australian city by paying simultaneous attention to both social vulnerability and severity of natural disasters. The simulation analysis has revealed how the variations in the size of five vulnerable clusters influence the social vulnerability of the city to natural disasters. The results of this research favour the fact that vulnerability and hazard are concomitant. Therefore, an effective risk assessment framework should pay simultaneous attention to both social vulnerability and various characteristics of disasters.