1990年から2016年の間に新聞メディアで報じられた地震学ニュースの内容分析

抄録

This study analyzes Japanese newspaper coverage of seismology from 1990 to 2016 and investigates how newspaper media portray the scientific ideas of seismology. In all, 19360 articles that contained references to scientific stories on seismology published by the Asahi Shimbun, the Yomiuri Shimbun, and the Mainichi Shimbun are collected. The content of newspaper coverage is classified into 14 topics using the cluster analysis with the distributed representation of articles which is generated by the machine learning method, Paragraph2Vec. The time-series analysis of articles reveals that a very large number of seismological reports are released immediately after big earthquakes occur but this number rapidly decreases within a few months. This means that the fleeting intense coverage greatly elevates the level of public concern about the seismic risk, while it fails to constitute the enduring forum for public debate of seismic risk issues. The content analysis with use of the natural language processing shows that the “earthquake prediction research” topic is covered most frequently and plays a pivotal role in seismological coverage. However, reports on “earthquake prediction research” topic are recently declining and obviously taking on a scientific research aspect. Results argue that the manner in which newspaper media report seismically related issues is undergoing major changes after the 2011 off the Pacific coast of Tohoku Earthquake. Specifically, media pay a great deal of attention to the issue of preparation measures for the future Nankai Trough earthquake and more news related to probabilistic assessments of earthquakes are conveyed as well. Such coverage would develop a public perception that the risk of coming earthquakes can only be described as the probabilistic assessment. In the societal debate about probabilistic seismic hazard maps, accountability and communication responsibilities of experts for the probabilistic assessments of seismic risk must be more strongly demanded from mass media and public. Moreover, evolving digital technologies create various types of information platforms such as digital media and SNS, some of which may provide a distorted depiction of seismic risk. Therefore, in order to realize effective risk communication in a rapidly changing media landscape, seismologists should not solely corroborate with legacy media organizations, but also support communication organizations which improve links between scientific community and media and enhance the accuracy of scientific coverage.