Abstract
Typhoon Hagibis (Typhoon No. 19 in the first year of Reiwa) landed on the Izu Peninsula on October 12, 2019 and brought record-breaking heavy rains across eastern Japan. The NHK Broadcasting Culture Research Institute conducted 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). This paper looks into the survey results from Marumori Town and Ishinomaki City in Miyagi Prefecture.
Among Miyagi Prefecture's municipalities, Marumori Town suffered the heaviest personal damage mainly due to the collapse of levees along three small/medium rivers that flow across the town. While 75% of the respondents were aware of the evacuation advisory, only 17% evacuated from home. May people remained at home because they did not think the area would be flooded. This clearly tells that it is crucial to inform residents of flood risks of small and medium rivers.
Meanwhile, Ishinomaki City did not have any levee collapse, but approximately 10,000 houses were flooded by inland flooding. The survey finds about 50% of the residents anticipated the flooding of their houses. It appears that many people decided not to take risks to evacuate during heavy rainstorms but to wait for the water to subside, by sheltering themselves by “vertical evacuation” to higher areas such as second floor of the house. Such evacuation behavior was likely to be driven by the fact that the area had been often flooded due to the ground subsidence cause by the Great East Japan Earthquake.
