The Anticipated Nankai Trough Earthquake and Tsunami in Japan: Determinant Factors of Residents? Pre-Event Evacuation Intentions

As a countermeasure against M8-9 class Nankai Trough earthquakes, the Japan Meteorological Agency started a service to release Nankai Trough Earthquake Extra Information (Megathrust Earth-quake Alert). This alert is released after an M8.0 or higher earthquake occurs and the possibility of a subsequent earthquake is evaluated to be higher than usual. This is an innovative attempt at disaster mitigation in Japan as it encourages residents in the predefined area to pre-evacuate for one week when tsunami risk is higher. However, the factors influenc-ing the evacuation behavior of residents are unknown. In this study, we investigated factors contributing to residents' pre-event evacuation intentions using the hierarchical multiple regression analysis. We focused on the extent to which the recognition of the hazards and risks of the Nankai Trough earthquake and the response to the Extra Information, which are changeable by the local governments' public relations activities, contributed to pre-event evacuation inten-tions after controlling for disaster-related general attitude and sociodemographic factors. Further, we paid special attention to residents' degree of recogni-tion of this information by checking the accuracy of their understanding of whether they lived within the pre-event evacuation area. The results showed that the recognition factors were relevant but less so than the general attitude toward disaster and more so than the sociodemographic factors. In addition, residents' recognition accuracy was low. Our results suggest that it is important for local governments to make adequate efforts to encourage residents to evacuate.

Automated summary

To counteract M8-9 class Nankai Trough earthquakes, the Japan Meteorological Agency introduced the Nankai Trough Earthquake Extra Information service. This service provides alerts after M8.0 or higher earthquakes, indicating a higher possibility of subsequent earthquakes. It encourages residents in the predefined area to pre-evacuate for one week when the tsunami risk is higher. Factors influencing residents' evacuation behavior are unknown, so this study investigated these factors and found that recognition of hazards and risks, along with the response to the Extra Information, contribute to pre-event evacuation intentions. However, residents' recognition accuracy is low, highlighting the importance of local governments' efforts to encourage evacuation.