Abstract
In late year, it has become easy to send information with the downsizing of information terminals have become easy. Twitter had been mostly used as an alternative method of telephone when the great east Japan Earthquake occurred at March 11, 2011. The reason why twitter had been used is because of some twitters features that the immediacy and diffusion of information dissemination is high. However, to identify some emergency and important information such as the help request, relief supplies and so on among a large number of tweets takes much time and labor. These problems had been also indicated after the Great East Japan Earthquake occurred. The research on the scrutiny information which is intended to suppress the dissemination of erroneous information that pay attention to related text and correcting misinformation. However be carried out to identify the necessary information is not intended. In this paper, in order to extract the emergency and important information with constant accuracy at the disaster situations, we tried to quantify the valid information on the situation and evaluate the extraction accuracy of the emergency and important information.
