Demographic transition and factors associated with remaining in place after the 2011 Fukushima nuclear disaster and related evacuation orders

Abstract

IntroductionDemographic changes as a result of evacuation in the acute phase of the 2011 Fukushima nuclear disaster are not well evaluated. We estimated post-disaster demographic transitions in Minamisoma City—located 14–38 km north of the nuclear plant—in the first month of the disaster; and identified demographic factors associated with the population remaining in the affected areas.Materials and methodsWe extracted data from the evacuation behavior survey administered to participants in the city between July 11, 2011 and April 30, 2013. Using mathematical models, we estimated the total population in the city after the disaster according to sex, age group, and administrative divisions of the city. To investigate factors associated with the population remaining in place after the disaster, a probit regression model was employed, taking into account sex, age, pre-disaster dwelling area, and household composition.ResultsThe overall population decline in Minamisoma City peaked 11 days after the disaster, when the population reached 7,107 people—11% of the pre-disaster level. The remaining population levels differed by area: 1.1% for mandatory evacuation zone, 12.5% for indoor sheltering zone, and 12.6% for other areas of the city. Based on multiple regression analyses, higher odds for remaining in place were observed among men (odds ratio 1.72 [95% confidence intervals 1.64–1.85]) than women; among people aged 40–64 years (1.40 [1.24–1.58]) than those aged 75 years or older; and among those living with the elderly, aged 70 years or older (1.18 [1.09–1.27]) or those living alone (1.71 [1.50–1.94]) than among those who were not.DiscussionDespite the evacuation order, some residents of mandatory evacuation zones remained in place, signaling the need for preparation to respond to their post-disaster needs. Indoor sheltering instructions may have accelerated voluntary evacuation, and this demonstrates the need for preventing potentially disorganized evacuation in future nuclear events.

Gender and life-stage dependent reactions to the risk of radioactive contamination: A survey experiment in Sweden

“…Dupont [16] suggests that two such factors would be gender and parenthood status. This corresponds to Morita et al's [8] findings regarding voluntary evacuation in Japan, which, in addition to gender and household type, found age to be a key factor. Whether the same would apply in another part of the world is not certain.…”

“…As for post-accident behavior, Zhang et al [9] found, three years after the accident, that few children and adult women returned after decontamination (e.g, 35% of children), but that elderly people returned to a high extent (86%). Moreover, those living with elderly relatives (70 years or older) were somewhat more likely (odds ratio 1.18) to remain in a pollution-affected area than those who did not [8]. Reasons stated for older people to stay are that the health risks of ionizing radiation are relatively low for them (compared to children and adolescents), that they more often than others have nostalgic feelings for their place of residence and, in tandem with gradually weakening health, and consider it economically and practically difficult to relocate and change lifestyle [9].…”

“…A month after the ban on returning had been lifted from one of its towns, Naraha, in 2015, only one in seven followed official advice and moved back [7]. Researchers cite citizens' concerns about the health risks of exposure to ionizing radiation as the main reason why many do not return [6,8]. A particularly low percentage of young adults, women and children return [9].…”

“…When not understood nor responded to properly, they often lead to prolonged conflicts with great human and financial costs [14]. Research has thus suggested that societies' preparedness for nuclear accidents can be improved if governing bodies gain a better understanding of how citizens' risk perception and behavior vary by demographics [8,15]. Dupont [16] suggests that two such factors would be gender and parenthood status.…”

“…The study's contribution will be two-fold. First, a body of knowledge on risk perception and behavior in relation to nuclear accidents and radiation has accumulated lately with several studies from Japan [8,9] implying that different geographically-focused research is needed to understand risk responses globally, to which the present study conducted in Northern Europe is an addition. Secondly, our results may be useful for future risk management.…”