The NHK Monthly Report on Broadcast Research
Online ISSN : 2433-5622
Print ISSN : 0288-0008
ISSN-L : 0288-0008
Report on the Survey on Residents' Disaster Information Awareness and Evacuation Behavior with Regards to Typhoon Hagibis in the First Year of Reiwa [Part I]
Levee Collapse along Chikuma River, Nagano Prefecture: What Made “Over 80 Percent Evacuation” Possible
Sayaka IRIE
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Keywords: NHK

2020 Volume 70 Issue 8 Pages 18-34


Typhoon Hagibis (Typhoon No. 19 in the first year of Reiwa) brought record–breaking heavy rains across eastern Japan. The Japan Meteorological Agency (JMA) issued “heavy rain emergency warnings” in record–high 13 prefectures. It resulted in a wide–area disaster that left damages in 13 prefectures, collapsing 128 levees along 71 rivers, in eight prefectures, including Chikuma River in Nagano Prefecture and Abukuma River in Fukushima Prefecture. The NHK Broadcasting Culture Research Institute held a public opinion survey of 3,000 residents in flooded areas in five municipalities: Nagano City (Nagano Prefecture), Marumori Town and Ishinomaki City (Miyagi Prefecture), and Motomiya City and Iwaki City (Fukushima Prefecture). The survey used a mail method. Among them, this paper examines the survey results from Nagano City. In Nagano City's Naganuma district, which was flooded after the levee collapse along the Chikuma, 84% of the residents evacuated from home to evacuation sites and other places. They started evacuating at an early stage, with 59% of the residents having evacuated before the water overflowed the banks along the Chikuma. When asked what had prompted them to evacuate, a number of respondents cited “disaster information,” “advice from people around them,” and “warnings from TV.” 62% percent of Naganuma residents were aware of the flooding risk of their houses from past flood experiences, flood hazard maps, and signboards showing expected inundation heights located in the district. In spite that the levee collapsed before dawn, the district managed to minimize human damage. This is presumably attributed to the residents'awareness on the disaster risks and appropriate responses to disaster information.

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