Using tweets extracted from Twitter during the Great Eastern Japan Earthquake 2011,social netw ork analysis techniques were used to generate and analyse the online networks that emerged at that time. People attempted to collect information about earthquakes and to communicate with friends throught the twi tter,and it is coping with the earthquake disaster.The aim was to identify active players for the Great Eastern Earthquake on twitter. We construct a communication network and calculate two centrality measures(degree a nd betweenness) on twitter. As a result,Important players during the Great Eastern Japan Earthquake were found to be: media reporters, news web site,social media volunteers, newspaper publishing company, celebrity, and autonomous computer program.
