Evolution Characteristics of Postearthquake Emergency Evacuation Demand Based on the Susceptible-Infective and System Dynamics Theories

Abstract

The heterogeneous composition of people living in various areas creates differences in the urban evacuation demand after an earthquake. In this study, four factors that can influence the evacuation demand are discussed: types of people, seismic intensity, evacuation pattern, and road capacity. Based on the formation mechanism of the evacuation demand, a mathematical model for evacuation demand evolution is established through the susceptible-infective (SI) theory to address these factors and their effects. Considering the dynamic feedbacks during the evacuation process and the spatiotemporal characteristics associated with the types of people, a microcosmic dynamic feedback model for evacuation demand prediction is proposed coupled with the system dynamics (SD) theory. Through comparative simulation of evacuation units experiencing the earthquake at different times and variations in land-use functions, the evolution characteristics of evacuation were simulated more intuitively. The dynamic prediction and evaluation model based on SI and SD in this paper can provide a new method for evacuation demand prediction. The analysis based on the simulation is of guiding significance for the evaluation of earthquake disaster prevention losses and the implementation of disaster prevention planning. It can also provide a reference for the prediction and decision-making of similar problems.