Collective response of human populations to large-scale emergencies

TL;DR

This study analyzes how human communication and mobility patterns change during large-scale emergencies, revealing localized spikes and global information spread, which can improve emergency detection and response strategies.

Contribution

It provides the first quantitative analysis of real-time societal behavioral responses to emergencies across multiple events, highlighting the spatial and temporal dynamics of communication and mobility changes.

Findings

Communication spikes are localized in space and time during emergencies.

Information about emergencies spreads globally, causing communication avalanches.

Behavioral changes can inform better emergency detection and response.

Abstract

Despite recent advances in uncovering the quantitative features of stationary human activity patterns, many applications, from pandemic prediction to emergency response, require an understanding of how these patterns change when the population encounters unfamiliar conditions. To explore societal response to external perturbations we identified real-time changes in communication and mobility patterns in the vicinity of eight emergencies, such as bomb attacks and earthquakes, comparing these with eight non-emergencies, like concerts and sporting events. We find that communication spikes accompanying emergencies are both spatially and temporally localized, but information about emergencies spreads globally, resulting in communication avalanches that engage in a significant manner the social network of eyewitnesses. These results offer a quantitative view of behavioral changes in human activity under extreme conditions, with potential long-term impact on emergency detection and response.