Abstract: Recent advances on human dynamics have focused on the normal patterns of human activities, with the quantitative understanding of human behavior under extreme events remaining a crucial missing chapter. This has a wide array of potential applications, ranging from emergency response and detection to traffic control and management. Previous studies have shown that human communications are both temporally and spatially localized following the onset of emergencies, indicating that social propagation is a primary means to propagate situational awareness. We study real anomalous events using country-wide mobile phone data, finding that information flow during emergencies is dominated by repeated communications. We further demonstrate that the observed communication patterns cannot be explained by inherent reciprocity in social networks, and are universal across different demographics.
Abstract: Large-scale emergencies and disasters are an ever-present threat to human society.With growing populations and looming threat of global climate change, the numbersof people at risk will continue to grow. Thus there is great need to optimize responseefforts from search and rescue to food and resource disbursement. Human dynamicsresearch offers a promising avenue to understand the behaviors of large populations, andmodern datasets derived from cutting-edge telecommunications such as online socialmedia and pervasive mobile phone systems bring a wealth of potential new information.Such massive data offers a promising complement to existing research efforts in disastersociology, which primarily focus on eyewitness interviews, surveys and other in-depthbut small-scale data.
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.