Emergency Warning Dissemination in a Multiplex Social Network

Abstract

Disasters vary in many characteristics, but their amount of forewarning-the amount of time remaining until the disaster strikes-is a crucial factor affecting the dissemination of emergency warnings. People can be warned by public safety officials through broadcast channels, such as commercial TV and radio, that transmit simultaneous warnings to mass audiences. In addition, however, warnings are also transmitted by peers through informal warning networks that operate through contagion from one person to another. This paper establishes an interdisciplinary agent-based model with Monte Carlo simulations to assess the relative effects of these broadcast and contagion processes in a multiplex social network. This multiplex approach models multiple channels of informal communication-phone, word-of-mouth, and social media-that vary in their attribute values. Each agent is an individual in a threatened community who, once warned, has a probability of warning others in their social network using one of these channels. The probability of an individual warning others is based on their warning source and the time remaining until disaster impact, among other variables. We model warning dissemination using simulation parameter values chosen from empirical studies of disaster warnings along with the spatial aspects of the Coos Bay, OR, USA and Seaside, OR, USA communities. Results indicate that the initial broadcast size has a negative correlation with the critical percolation threshold, which varies from approximately 1-5%, depending on the size of an initial broadcast. A sensitivity analysis on the model parameters indicates that, along with initial broadcast size and sharing probability, forewarning and confidence in the warning significantly affect the total number of warning recipients. The results generated from this study identify areas for future research and can inform community officials about the effects of event and community characteristics on the dissemination of emergency warnings in their communities.

Agent-Based Simulation of Hurricane Risk Information Dissemination

“…After that, the impact of an increase in the KOL number decreases where its effect is negligible from 160 -280 KOLs. This finding is also consistent with another warning study that the impact of official warning increases rapidly at the beginning and then declines significantly later (Koll et al, 2023). While we conducted a sensitivity analysis on the KOL number, future research could use real social data to analyze the "leader-follower" effect (King and Cowlishaw, 2009).…”

Effectiveness of a Dam-Breach Flood Alert in Mitigating Life Losses: A Spatiotemporal Sectorisation Analysis in a High-Density Urban Area in Brazil

“…Water 2023, 15, x FOR PEER REVIEW 3 of 20 stakeholders involved in hazard identification and warning issuance [46], the mechanisms of warning dissemination and their influence [47,48], as well as the preparedness and prior knowledge of the population regarding mobilisation and evacuation to safe places [49,50]. The spatial and temporal sectorisation of alerts and evacuations adapting the system to the specific characteristics of each sector can bring significant benefits in terms of system efficiency [51][52][53].…”

“…A significant advantage of applying these models, which has been little explored in the literature, is the ability to measure, in advance, the efficiency of alert and evacuation systems with different characteristics, such as the decision-making process of stakeholders involved in hazard identification and warning issuance [46], the mechanisms of warning dissemination and their influence [47,48], as well as the preparedness and prior knowledge of the population regarding mobilisation and evacuation to safe places [49,50]. The spatial and temporal sectorisation of alerts and evacuations adapting the system to the specific characteristics of each sector can bring significant benefits in terms of system efficiency [51][52][53].…”