Rescue Activity for the Great East Japan Earthquake Based on a Website that Extracts Rescue Requests from the Net

[Abstract] In the early stages of the Great East Japan Earthquake, a vast number of tweets were related to high-urgency rescue requests; however, most of these tweets were buried under many other tweets, including some well-intentioned retweets of the rescue requests. To better handle such a situation, the authors have developed and published a website that automatically lists similar statements to extract rescue requests from Twitter on March 16, 2011. This paper describes not only the technology of the system but also the start of a rescue project #99japan. The project takes particular note of the progress and completion reports of the rescue situations, using this site as sources of rescue information. Note that #99japan originated from a thread of the Japanese textboard 2channel, which was launched by some volunteers within two hours of the disaster’s occurrence.