Analysis of Twitter hashtag trend in the Great East Japan Earthquake: Towards the use of ICT at the time of the earthquake

Abstract

　Based on the data of Twitter while a week after the Great East Japan Earthquake, this study analyzes the communications that use the hashtag at the time of the earthquake in order to make proposals towards the efficient use in the future. From the analysis of basic statistics and tendencies of tweets for announcement of new hashtags, it was clarified that defining official hashtag is efficient. Content analysis of the hashtag showed that most of hashtags have been used along the purpose, although it is necessary to distinguish between hashtags of supplies and relief. Furthermore, from the usage trends of municipalities' hashtags in disaster area, it was found that Twitter has been used in the disaster areas despite the poor communication infrastructure. Those results suggested that the promotion of local communication in such municipal level would be meaningful.