How Did We Used Twitter, How Communicate in Twitter at Catastrophic Earthquake in Japan

The Great East Japan Earthquake caused devastating damage to infrastructure and loss of life. Many people used social media to communicate and share information through the series of earthquake events and aftershocks. We analyzed over 400 million Tweets and the Twitter network in Japan before and after the earthquake, which revealed the earthquake that occurred in the Twitter milieu itself. We performed analyses of two kinds. As a result, we suggest that the role of Twitter as a means to share information changed during the earthquake period.