2025 Volume 81 Issue 13 Article ID: 24-13528
In this study, we evaluated warning time distributions of Earthquake Early Warning (EEW) provided by JMA for six resent major earthquakes, and compared the warning time available to the population exposed to high seismic intensity by superimposing the interpolated estimated seismic intensity distribution based on the observed seismic intensity and the population distribution for each earthquake. In general, higher intensity areas are provided with shorter warning time. In inland crustal earthquakes, it is likely that warnings may not reach high intensity areas around the epicentral region in appropriate time. Conversely, in oceanic plate earthquakes, it is expected that warning time is effective even in high intensity areas. Next, spatial zoning was applied based on the temporal order of EEW announcements, P-wave arrival and S-wave arrival to remind people of the importance of appropriate safety actions for self-protection in each zone. Finally, we modeled the time required for the announcement of EEWs for prediction of warning time in future earthquakes.
