A threshold model of social contagion process for evacuation decision making

Individual evacuation decision is often characterized by the influence of one’s social network. In this paper a threshold model of social contagion, originally proposed in network science literature, is presented to characterize this social influence in evacuation decision making process. Initiated by a single agent, the condition of a cascade when a portion of the population decides to evacuate has been derived from the model. Simulation models are also developed to investigate the effects of community mixing pattern and initial seed on cascade propagation and the effect of previous time-steps considered by the agents on average cascade size. Insights related to social influence include the significant role of mixing pattern among communities in the network and the role of initial seed on cascade propagation. Specifically, faster propagation of warning is observed in community networks with greater inter-community connections.