Construction of an evacuee placement model for tsunami shelters considering physical distancing to prevent COVID-19...

Earthquakes and tsunamis are expected to occur within the next 30 years along Japan's Nankai Trough. Existing disaster prevention plans and calculated evacuation capacities in the coastal areas that would be affected do not account for physical distancing in the context of COVID-19. Therefore, we developed a tsunami evacuation placement model incorporating physical distance guidelines for infection control and living space per person into calculations of evacuation center accommodation capacities in Aki City, Kochi Prefecture. Using available administrative, population, and tsunami inundation data, we counted and mapped evacuation centers in the estimated inundated area within three zones constructed for smooth evacuation using the ArcGIS software Build Balanced Zones Tool. We calculated the space per evacuee using the Sphere handbook standard of 3.5 m² or double the Sphere standard at 7 m² plus the recommended physical distance of 11 m² per person. We then compared the results with planned capacities. A total of 27 shelters are located in the area projected to be inundated at depths of 0.3-10 m, and their planned capacity, 2 m² for each evacuee, would accommodate 32.9% of Aki's population and result in 9639 unaccommodated evacuees. Allotting 14.5 m² (living space) or 18 m² (living space plus space to maintain physical distancing) would reduce accommodation capacities to 57.1% and 28.6% (12,133 and 12,371 unaccommodated evacuees, respectively). Given these accommodation shortages, we recommend that evacuation centers are set aside for vulnerable people and that alternative evacuation sites such as parking lots and mountain campsites are preplanned.