Seismic intensity and typhoon categories: the need for quantitative clarity in Japanese disaster communication

We examine the Japanese seismic intensity scale and the typhoon categories issued by the Japan Meteorological Agency (JMA). Most of the official information is presented in non-quantitative and experience-based expressions, which may hinder accurate understanding and international comparison. We argue that these expressions should be reformulated in quantitative terms. In particular, we revisit the mathematical definition of the JMA seismic scale as provided on its website, and we propose a more precise formulation, together with explanatory examples and comparisons with international standards.