COMMUNITIES’ DISASTER PREPAREDNESS PROMOTED EVACUATION: A CASE STUDY OF NAGANO CITY DAMAGED BY THE CHIKUMA RIVER FLOODS CAUSED BY TYPHOON HAGIBIS

Abstract

This study examined the evacuation behavior of two communities—Naganuma and Toyono—in Nagano City, Japan, during typhoon Hagibis. Only two casualties were reported, despite the large size of the inundated area and significant building damage. We analyzed the relationship between (1) the numerical statement of aggregated evacuation behavior, (2) social and hazard circumstances, and (3) the social background, including disaster preparedness plans formulated by the community. The study focused on “the details” of evacuation promotion factors revealed by previous research, rather than “the existence or absence” of such factors. Data were collected from newspaper articles, a post-interview survey conducted by Kansai Television Co. Ltd., minutes from the flood control meetings in the flooded area, and district disaster management plans. The results revealed that the main factors promoting evacuation action differed for the two communities due to their disaster preparedness styles. While Naganuma established a specific (a particular measurement of the water level of the Chikuma River) and socially agreed-upon criterion for evacuation, Toyono had experienced several inland flooding events. It was found that both communities participated in the flood control meetings, formed organizations for voluntary disaster mitigation action, and cultivated common awareness regarding “the sign of a dangerous situation” and “what information is important for evacuation.”