Linguistic analysis of Japanese tsunami evacuation calls

Tsunami evacuation calls were collected from 38 autonomous bodies in Japan and categorized into `preparation', `advisory', and `directive' categories based on the urgency level. This study analyzed these calls from a linguistic viewpoint in terms of language quantity, sentence complexity, and information types included in a call. The analysis obtained the following results: 1) the amount and complexity of language increases as the urgency level increases; 2) many of the local governments adopt the same terms for tsunami alerts used by the Weather Bureau instead of using the legal terms `preparation', `advisory', or `directive'; 3) most evacuation orders in a call are expressed as requests (“Please do ~”) instead of as imperatives; and 4) there are no significant differences in sentences and content used in advisory calls compared with directive calls.