During a disaster, information spreads through social media. Although information that can save lives exists in social media, it can be difficult to find because it is buried under a sea of unverified information. One challenge in improving the use of social media for disaster management is to facilitate the spread of actionable information that improves people’s well-being and at the same time reduce the spread of misinformation that confuses people and interferes with the discovery of useful information. To this end, we study the psychology of message forwarding in social media. Based on the understanding of the psychology, we develop recommendations for designing tools that augment the forwarding decisions of individuals such that useful information spreads in social media. Here, we present the results from analyzing the forwarding of tweets related to the disasters caused by the Great East Japan Earthquake in 2011. The results from questionnaires suggest that people will be more likely to share a disaster-related message in a social media environment when they perceive the message as more important, accurate, anxiety provoking, familiar, informative, and fluent. The implications of the results on improving the quality of information in social media during disaster response are discussed.