  Hurricane Sandy was one of the deadliest and costliest of hurricanes over the
past few decades. Many states experienced significant power outage, however
many people used social media to communicate while having limited or no access
to traditional information sources. In this study, we explored the evolution of
various communication patterns using machine learning techniques and determined
user concerns that emerged over the course of Hurricane Sandy. The original
data included ~52M tweets coming from ~13M users between October 14, 2012 and
November 12, 2012. We run topic model on ~763K tweets from top 4,029 most
frequent users who tweeted about Sandy at least 100 times. We identified 250
well-defined communication patterns based on perplexity. Conversations of most
frequent and relevant users indicate the evolution of numerous storm-phase
(warning, response, and recovery) specific topics. People were also concerned
about storm location and time, media coverage, and activities of political
leaders and celebrities. We also present each relevant keyword that contributed
to one particular pattern of user concerns. Such keywords would be particularly
meaningful in targeted information spreading and effective crisis communication
in similar major disasters. Each of these words can also be helpful for
efficient hash-tagging to reach target audience as needed via social media. The
pattern recognition approach of this study can be used in identifying real time
user needs in future crises.
