Fukushima Nuclear Disaster displacement: How far people moved and determinants of evacuation destinations

Author’s Accepted Manuscript Fukushima Nuclear Disaster displacement: How far people moved and determinants of evacuation destinations Xuan Bien Do www.elsevier.com/locate/ijdr

PII: DOI: Reference:

S2212-4209(18)30416-3 https://doi.org/10.1016/j.ijdrr.2018.10.009 IJDRR994

To appear in: International Journal of Disaster Risk Reduction Received date: 2 April 2018 Revised date: 12 October 2018 Accepted date: 12 October 2018 Cite this article as: Xuan Bien Do, Fukushima Nuclear Disaster displacement: How far people moved and determinants of evacuation destinations, International Journal of Disaster Risk Reduction, https://doi.org/10.1016/j.ijdrr.2018.10.009 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Tittle: Fukushima Nuclear Disaster displacement:

How far people moved and determinants of evacuation destinations Reference IJDRR 994 Author: Given name: Xuan Bien Family name: Do Affiliation: 1. Department of Geography, Graduate School of Letters, Hiroshima University, Japan 2. Faculty of Geography, University of Social Sciences and Humanities, Vietnam National University-Ho Chi Minh City. Address: A222, Faculty of Geography, University of Social Sciences and Humanities, Vietnam National University-Ho Chi Minh City, 10-12 Dinh Tien Hoang street, District 1, Ho Chi Minh City, Vietnam. Tel (work): +84-28-38293828 (ext 130) Cellphone: +84-909440547 email: [email protected]; [email protected] Corresponding author: Given name: Xuan Bien Family name: Do Address: A222, Faculty of Geography, University of Social Sciences and Humanities, Vietnam National University-Ho Chi Minh City, 10-12 Dinh Tien Hoang street, District 1, Ho Chi Minh City, Vietnam. Tel (work): +84-28-38293828 (ext 130) Cellphone: +84-909440547 email: [email protected]; [email protected]

Fukushima Nuclear Disaster displacement: How far people moved and determinants of evacuation destinations Abstract The accident at the Fukushima Daiichi Nuclear Power Plant triggered a massive evacuation from affected areas. Although several studies have investigated various aspects of the evacuation, little attention has been paid to examining where and why people moved to different evacuation locations. Based on the data collected from a questionnaire survey of 289 evacuees from Minamisoma City, this paper discusses the temporal-spatial features of the evacuation while emphasizing evacuation distances and the factors that influenced the selection of evacuation locations. The study found that people increased their evacuation distance from the nuclear power plant and reached their furthest evacuation destinations shortly after the accident. The fear of radiation exposure only has an impact on selecting evacuation locations briefly after the accident. The study found that evacuees whose home location was in the restricted areas, those engaged in permanent jobs, and those who had young children at the time of the nuclear accident tended to evacuate shorter distances. No statistical evidence has been found regarding the association between age, gender, or the educational and economic status of evacuees and evacuation destinations. The paper suggests that the decision regarding evacuation destinations is strongly driven by human networks and recommendations of local governments and acquaintances and is influenced less by job-related matters, safety from radiation exposure, accommodation availability, and convenient access to social amenities. Keywords: disaster migration, Fukushima nuclear accident, temporal-spatial patterns of evacuation, evacuation location selection, evacuation distance Highlights  Evacuees increased their distance from the nuclear power plant in the early stage after the accident.  The spatial distribution of the evacuation is consistent with the Law of Migration and the gravity model of migration.  The fear of radiation shows the influence on evacuation distance only in the immediate aftermath of the nuclear accident.  Evacuation distance is driven by human networks, participants’ proximity to the nuclear power plant, their children’s schooling, and job-related matters. I. INTRODUCTION Displacement is recognized as one of the most common survival strategies following disaster events, and it has been well documented in the literature (Hugo, 1996; Myers, 1993). Disasters may lead to forced or voluntary migration (Peterson, 1958) although the distinction between these two types of migration is unclear (Speare, 1974). In many cases, people must move because they perceive that they are facing a life-threatening situation such as the danger of volcanic eruptions, extreme hurricanes, chemical spills, or nuclear disasters. They may also migrate due to damage to their home, livelihood, and social facilities and infrastructures (Frankenberg et al., 2014). In these cases, disasters worsen the living conditions in their home location and push them to seek places with better conditions. Many research studies have examined migration behaviors such as deciding whether to move or stay (Gray et al., 2009; Wolpert, 1966), where to go (Findlay, 2011; Henry et al, 2004; Kniveton et al., 2008) and return or not return (Fussell et al., 2010; Groen & Polivka, 2010;

Nakayama et al., 2017). Another great volume of literature focused on exploring the determinants as well as factors influencing migration behaviors such as living conditions, socio-economic status, and migrants’ demographic characteristics (Cahyanto & PenningtonGray, 2015; Elliott & Pais, 2006; Hasan et al., 2011; Smith & McCarty, 2009; Van Willigen et al., 2005). Disaster-induced population movements lead to demographic changes and other social impacts in not only the affected areas but also in the destination locations (Kolbe et al., 2010; Swanson et al., 2009; Van Willigen et al., 2005). Understanding the above dynamics of disaster-induced migration is crucial to developing appropriate policies associated with postdisaster rehabilitation. However, most research regarding disaster migration focuses on natural disasters. Very few studies on migration due to technological disasters exist in the literature, possibly because such technological disasters occur with considerably lower frequency than natural disasters. Even fewer research studies on nuclear disaster migration can be found. Therefore, research to elucidate migration mechanisms following a nuclear disaster is believed to have a valuable contribution to both academics and policymaking. The Fukushima nuclear disaster caused the evacuation of about 164,000 people from the evacuation zones as well as adjacent areas including mandatory and voluntary evacuation. The number of evacuees has gradually decreased (Figure 1) as people have returned to their homes since the situation at the facility has stabilized and considerable decontamination and reconstruction efforts have been made. Statistical data reveals that evacuees have moved to different locations in all of Japan’s 47 prefectures, and the evacuation’s spatial distribution has changed over time (Japan Reconstruction Agency, 2014). At its peak in May 2012, about 62% (102,000 people) evacuated inside the Fukushima prefecture, and 38% (62,000 people) evacuated outside of it. In February 2017, the total number of evacuees decreased to about 79,000 people; of which, 50% stayed inside Fukushima prefecture, and 50% remained evacuated outside of it (Fukushima Prefectural Office, 2017). This indicates that the return rate of those evacuated outside their home prefecture is much lower than those evacuated within their home prefecture (38.1% and 61.4%, respectively).

Figure 1: Number of evacuees from Fukushima prefecture

Source: Fukushima Prefecture Office, 2017

Displacement caused by the nuclear accident at the Fukushima Daiichi nuclear power plant (NPP) has drawn the attention of researchers from various disciplines, including geographers. The demographic impacts of the nuclear accident evacuation; an accelerated depopulation and aging population have been observed in the Tohoku region, especially the Fukushima prefecture (HINO, 2011; Ishikawa et al., 2012). The spatial distribution of evacuees has also been investigated by Ishikawa (2012) and Oda (2012) mainly through statistical analysis. Additionally, ISODA (2011) examined the differences in evacuation patterns between different groups of evacuees based on their age and sex. Horikawa (2017) used ethnographic narratives to explore the main causes of family and community division following the nuclear accident and focused on different perspectives on the risk of radiation exposure among different social groups. In their study of evacuation behavior, Song et al. (2013) also attempted to identify possible routes of evacuation shortly after the disaster and simulated these with models. Apart from this research, the determinants that shape the decision to evacuate and return have also been studied (Orita et al., 2013; Zhang et al., 2014). Although existing research has examined various aspects of evacuation patterns, the question of where people evacuated to has not been explicitly studied, and little attention has been paid to examining evacuation distances. The Law of Migration states that in migration, people normally seek to migrate to locations close to their home areas rather than to distant locations (Ravenstein, 1889). However, in radiation protection, moving further distances from the source of radioactivity lessens radiation exposure (IAEA, 2011b). Therefore, according to this scientific guideline, people are believed to move the distance that they perceive safe from the radiation exposure. Moreover, why nuclear accident evacuees moved to different locations and what factors influence the process of choosing an evacuation destination are not currently well understood. Research on temporal-spatial patterns of the Fukushima nuclear accident evacuation, especially how far people moved from the nuclear power plant, as well as factors that influence the process of choosing an evacuation location will help elucidate evacuation mechanisms following a nuclear disaster which have not been well documented in the literature of the disaster migration domain. Furthermore, understanding where people evacuated to, who moved to short distant locations, who moved to long distant locations, and how much the fear of radiation impacts on the process of choosing an evacuation destinations is believed a valuable science-based reference for making appropriate policies related to evacuation support and rehabilitation in a nuclear disaster in general and for evacuees of the Fukushima nuclear accident in particular, especially those related to housing, employment, and school support. Literature Review Research on disaster migration has been well documented although most of it is on natural disasters. Hugo (1996) concluded that migration, whether permanent or temporary, has always been perceived as a traditional response to the impacts of a disaster. Migration from a natural disaster is well known because of their frequent occurrence, and the impacts of the hazards are observed to be on the rise (Abramovitz, 2001; Hunter, 2005). In Bangladesh, severe flood and river erosion causes the displacement of a hundred people annually. People also tend to resettle in regions with a lower risk of natural hazards rather than disaster-prone areas. One example is the outmigration of people from New Orleans. This flood- and

cyclone-prone area has been experiencing a declining population, especially after Hurricane Katrina hit this low-lying land in 2005 (Vigdor, 2008). However, in many cases, natural disasters lead to temporary relocation but not the permanent change of residential location (Hunter, 2005). Some people decide to remain in areas where natural hazards occur frequently because it is where they earn a living, and in some cases, the area becomes part of their cultural identity (Zaman, 1991). Movement decisions and their determinants The reasons disasters cause migration have been elucidated. In catastrophic disasters, people are forced to move or decide to move when facing a life-threatening situation (Frankenberg et al., 2014; Hugo, 1996) such as earthquakes, floods, tropical cyclones, and nuclear disasters (Kasperson & Pijawka, 1985). However, in many other cases, a disaster is among multiple causes that trigger the migration through both physical and social damage (Black et al., 2013). Wolpert (1966) proposed the stress-tolerance model to explain how the hazards caused by disasters trigger the movement of affected people. At a certain level of stress, people may decide to remain in affected areas with some negative but stable impacts rather than face the stress caused by changing their residence and living environment (Wolpert, 1966). This situation is similar to the immobility paradox concept which states that most potential migrants may decide to remain in their current residence if possible even though there are possible external economic and social gains to be made by moving (Fischer & Malmberg, 2001). However, if additional stresses caused by disasters surpass the stress threshold, people are likely to move (Wolpert, 1966). Property damage and losing one’s source of income following a disaster are often reasons for migration (Black et al., 2013; Frankenberg et al., 2014). Since hazards, either natural or technological, have already been recognized as the main driver in disaster migration, research attention has been focused on migration behavior, including determining who will move, where people will move, and how they will choose the destination. Previous research has noted that the decision to evacuate from disaster-affected areas is generally associated with evacuees’ socio-demographic characteristics. First, gender and age show a consistent association with the decision to evacuate in natural disasters, typically in hurricanes, earthquakes, and floods; often, males and older people are less likely to evacuate (Cahyanto & Pennington-Gray, 2015; Elliott & Pais, 2006; Smith & McCarty, 2009). In nuclear disasters, a similar trend is also found. Demographic data collected before and after the nuclear accident in Fukushima also reveal demographic changes, particularly in age and gender (Fukushima Prefectural Office, 2015). In the affected areas, there was a significant increase in the rate of elderly persons (i.e. over 65-years of age) while there was a rapid decrease in the youngest age group (i.e. under 15-years of age). A slightly higher evacuation rate of females than males was also observed. Having young children is also recognized as a factor that influences the decision to evacuate in natural disasters and nuclear accidents (ISODA, 2011; Medina & Moraca, 2016; Solis et al., 2010; Smith & McCarty, 2009). Social status is also associated with migration behaviors caused by disasters. The influence of education on evacuation behavior has been found in the literature of disaster migration although the influence of educational background is adversely observed. While Hasan et al. (2011) found that in Hurricane Ivan-affected areas, residents with higher levels of education were more likely to evacuate than those with lower, the opposite trend was observed by Paul (2012) after Cyclone Sidr in Bangladesh and by Thiede & Brown (2013)

after Hurricane Katrina. In addition to these factors, the literature on disaster migration also suggests that economic status is an influential variable which affects evacuation behavior. In natural disasters, Van Willigen et al. (2005) found that people with a low-income status are more likely to evacuate in a hurricane event, particularly during Hurricane Floyd in the USA. However, Elliott & Pais (2006) and Hasan et al. (2011) have found that low-income people were associated with a decreased likelihood of evacuation during Hurricane Katrina and Hurricane Ivan, respectively. Another strong predictor of evacuation intention is risk perception; people who perceive higher risks of a hazard are more likely to evacuate from the source of danger (Nozawa et al., 2008; Riad et al., 1999). Technological disaster has also been recognized a cause of population displacement, for example, hazardous waste contamination in Love Canal, New York in 1978, a chemical spill in Bhopal, India in 1984, and nuclear disasters in Three Mile Island, Pennsylvania in 1979, in Chernobyl, Russia in 1986, and most recently, in Fukushima, Japan in 2011 although technologically-induced migration is less common in the literature. Contamination caused by toxic chemicals in the Love Canal disposal site led to the evacuation of 239 families living in adjacent areas in August 1978, and a total of about 700 families permanently relocated in 1979 (Fletcher, 2002). The fatal gas leak at the Union Carbide India Limited plant in Bhopal in 1984 was one of the worst industrial disasters in India’s history; it killed about 5,000 people within two days after the disaster, and about 200,000 people were exposed to the leaked gas and evacuated temporarily (Varma & Varma, 2005). The Three Mile Island (TMI) nuclear accident occurred in the US in 1979; it caused a large-scale evacuation of about 140,000 people who had to leave their home within one day after the accident. In the following days, half of the population of 663,500 within a 20-mile radius from the site was also evacuated (USNRC, 2013) although only 1.7 percent of the population within 5 miles from the plant moved permanently to other places (Goldhaber et al., 1983). The most severe nuclear accident was in Chernobyl, Russia in 1986; it caused a massive 350,400-person relocation both temporarily and permanently within 1 year after the accident (World Bank, 2002). The impacts of this technological disaster on population movement can also be seen in neighboring countries such as Belarus due to concerns regarding health risks (Kavanova, 2008). Although technological disaster-induced migration has been researched, very few studies focus on factors that shape people’s migration behavior. A study on population mobility in Belarus caused by the Chernobyl nuclear accident in 1986 found that the major reasons for migration were health concerns and the affected areas’ decreased economic less attractiveness (Kavanova, 2008). This study also revealed that the main reason for not migrating was identified as family ties. Many people, most of them elderly, did not want to move because of their deep fondness and love for their homeland as well as its agricultural life. There has been some research on evacuation behavior in the TMI nuclear accident. In one of the first attempts to document the evacuation process caused by a nuclear disaster, Zeigler et al. (1981) found no statistically significant differences between those who evacuated and those did not when their occupation, income, age, and education were compared. The reasons for evacuating and not evacuating were identified. While concerns about personal safety are the most influential factor in evacuating, the absence of an official evacuation order is the most critical factor in choosing not to evacuate (Zeigler et al., 1981). Another study conducted by Cutter & Barnes (1982) found four main reasons for evacuation following the TMI accident: the governor’s evacuation advisory, anticipated consequences, uncertainty and conflicting information about the accident, and the evacuation of friends and neighbors. The study also suggests that the primary determinant of those evacuated are living

closer to the reactor while younger age and higher education levels show a weak association with the decision to evacuate, and occupation has no influence (Cutter & Barnes, 1982). However, Stallings (1984) found the proximity from the nuclear power plant, job status, and demographic differences between those evacuated and those did not do so. It was found that the extent of evacuation decreases by the distance from the nuclear reactor site and those who chose not to evacuate were primarily due to their inability to leave their job and were likely over 70 years of age (Stallings, 1984). Since the occurrence of the Fukushima nuclear disaster in Japan in March 2011, several studies have been conducted regarding population displacement. ISODA (2011) studied the age and sex of evacuees from the nuclear crisis. The study found that among voluntary evacuees, disproportionately more children and females aged 30–40, probably mothers and their children, moved out of the Fukushima prefecture. Meanwhile, males aged 45–59 and elderly aged 75 or older tended to stay within Fukushima and near their hometown. HINO (2011), Y. Ishikawa (2012), Higuchi et al. (2012), and Abe (2014) investigated the demographic impacts of the nuclear accident in the three most heavily affected prefectures: Iwate, Miyagi, and Fukushima. The rapid increase of net out-migration was observed, especially in Fukushima prefecture, and this anticipates the acceleration of depopulation and labor shortages in the affected areas. The Fukushima prefecture’s government has conducted a large survey of 62,812 evacuated households about their postevacuation lives. The results released on April 28, 2014 revealed that about half of the evacuees have been separated from their family members. Sixty-seven percent of respondents confirmed that their family members have been suffering physical and psychological distress (Fukushima on the Globe, 2014). Family separation due to the evacuation has also been reported, and the difference in perceptions of radiation risk is the explanation of the large number of husbands remaining in their home location while their wives and children moved to distant locations (Horikawa, 2017). Using human capital theory, ISODA (2011) examined the reasons why evacuees continue to leave (or return) and what influences people to move away from the nuclear disaster-affected sites. According to findings from ISODA's research, factors that keep people evacuated or to make them return to their home are not physical capital such as owned houses and pecuniary concerns but their social networks. This is because physical capital can be easily compensated. However, it is difficult to quantify and fully compensate social relationships. In contrast, the fear of health risks from radiation, the uncertainty of how long the radiation problem will persist, and the uncertainty of the immediate future are recognized as factors influencing their decision to migrate out of their original location. The determinants of returning home post Fukushima nuclear disaster were also found by another research study that the female group who previously lived in areas with high ambient doses of radiation and those who felt anxious about the negative effects of radiation its negative effects are less likely to return (Orita et al., 2013). Migration destination and its influencing factors One of the main questions in migration research is where people migrate to and why people choose a specific location. Understanding the destination patterns of disaster migration and factors that influence destination choices are relatively limited (Findlay, 2011) due to the difficulties involved in tracking migrants' residential locations post-disaster since their migration destinations are unknown in many cases, particularly in sudden disaster events such as a nuclear disaster (Hunter, 2005). In the literature, several migration theories

which apply to migration in general but not specifically to disaster migration have been found. The first and traditional concept considering the spatial patterns of migration destinations is the Law of Migration. Ravenstein (1889) studied the effects of distance in cultural and spatial interaction and, based on his empirical observations, suggested that the volume of migrants declines as the distance from their location of origin increases, and short distance movements are most common. Although the reasons why long-distance migration is not favorable for most migrants were not explained by Ravenstein, the high cost of travel seems to be the most obvious reason and possibly the higher degree of differences in the physical environment as well as social and cultural conditions when compared to home locations. Gender characteristics also impact the migration destination as females are more migratory than males in short distant migration, but males are common in farther distance movement (Ravenstein, 1889). Another theoretical model used to examine migration flow is the gravity model in migration. The model is derived from Newton's law of gravity which states the attracting force between two objects is proportional to their mass and inversely proportional to the square distance between them. Stewart (1942) and Zipf (1946) have adopted this law for migration modeling to examine migration flow in the USA; the objects are replaced by locations and their masses are understood as the importance of the locations. The importance can be based on the location’s population size, gross domestic production, or role as a political, cultural, or commercial center. The gravity model in migration shares Ravenstein's concept of distance decay in migration but provides further explanation for Ravenstein's observation that although short-distance migration is most common, people pursuing longdistance movement normally go to great centers of commerce or industry. The contribution of this model is elucidating migration flows to locations which have larger populations and more influence in economics, culture, and politics. Acknowledging that the decision to migrate is shaped by a variety of factors which affect potential migrants differently, Lee (1966) introduced another framework called the push and pull theory in migration. According to this theory, a migration decision is made by considering four groups of factors: factors associated with the area of origin, factors associated with the area of destination, intervening obstacles, and personal factors. Both the location of origin and destination may have both negative factors (pushes) and positive factors (pulls), and the evaluation of these is dependent on personal contacts and sources of acquired information. It is also influenced by intervening obstacles such as distance, transportation costs, and institutional restriction (Lee, 1966). Adopting this theory to examine spatial patterns of migration suggests that the decision to migrate to a destination can be made when the balance of pull factors favors the destination over the location of origin and overcomes intervening obstacles. The push and pull theory in migration has added an important factor, which is the personal factor. People’s demographic and socio-economic characteristics may facilitate or retard migration (Lee, 1966). Previous migration experience and human networks are believed to be an influential factor that shapes the choice of a migration destination (Boyd, 1989; Faist, 1997; Haug, 2008). The above migration theories seem to illustrate the patterns of voluntary and planned migration, typically labor migration. However, disaster-induced migration is often unplanned and is forced relocation in many cases. Empirical research on disaster-migration location choices is rarely found in the literature. Findlay (2011) reviewed the research literature on environmental migration, which is mostly related to natural disasters, and pointed out four main aspects which help researchers understand the destinations of environmental migration.

First, migration associated with environmental changes, particularly flood and drought, predominately involves temporary evacuation and short-distance movement (Bassett & Turner, 2007; Renaud et al., 2007). Second, the choice of destination is likely to be driven by non-environmental factors such as political, economic, and demographic context (Kniveton et al., 2008) as well as social interaction with other people in one’s family and community (Warner et al., 2009). Third, it is less likely that environmental change will cause long-term emigration even in an extreme event such as a cyclone (Kniveton et al., 2008), and if the out-migration occurs, most will move within their social and cultural territory (Warner et al., 2009). Finally, disaster movers are less tolerant of poor environmental circumstances at other places; therefore, if they are forced to move, they will only settle in a destination that offers favorable economic, social, and environmental conditions that allow long-term settlement (Henry et al., 2004). The question of where people move after a nuclear disaster has been partly answered by previous research. Zeigler et al. (1981), based on the survey of 150 voluntarily evacuated households in the areas beyond 15 miles from the TMI reactor, have illustrated the spatial distribution of evacuation destinations, emphasizing evacuation distance and direction. The study suggested that evacuation destinations are widely dispersed. The average evacuation distance is within a 85-mile radius from the reactor, and about half of the respondents moved within 45–90 miles. The study also found a preference to move in the northwest direction, and respondents were reluctant to move to densely populated metropolitan areas although the authors mentioned that these observations are still biased and need further investigation into the concrete reasons (Zeigler et al., 1981). Some other research has just focused on the evacuation decision and the association between the socio-demographic characteristics of residents surrounding the TMI reactor (Cutter & Barnes, 1982; Stallings, 1984) but did not investigate the spatial distribution of evacuation destinations. Other aspects of spatial patterns of evacuation, particularly what influences the choice of an evacuation destination and whether people with different socio-demographic characteristics choose evacuation destinations differently, remain unknown. In the Fukushima nuclear disaster, evacuees’ evacuation destinations have been illustrated by several researchers. Oda (2011) and Ishikawa (2012) used statistical data to examine the distribution of evacuees from the affected areas based on their evacuation destinations. Both noted that evacuation destinations are widely dispersed across the country but short-distance movement within Fukushima prefecture and neighboring prefectures is most common. It has also been observed that moving to eastern Japan, especially in Tokyo’s metropolitan areas, is preferable (Ishikawa, 2012). A certain proportion of evacuees moving long distances even farther west of Osaka’s metropolitan areas were partly due to the ample support offered by local governments (Ishikawa, 2012). Although other studies have suggested that people with different demographic characteristics (e.g., age and gender) show different evacuation patterns (HINO, 2011; Horikawa, 2017; ISODA, 2011) but the focus is mainly on the differences in the decision to migrate and the duration of migration rather than on evacuation destinations. The existing knowledge is insufficient to explain the spatial and temporal process of evacuation caused by the Fukushima nuclear accident, factors that impact the choice of an evacuation destination, and how the radiation hazard from the nuclear accident influenced evacuation patterns. To fill the above knowledge gap, this paper aims to discuss the spatial aspects of the Fukushima nuclear accident evacuation while focusing on the evacuation destinations and particularly the distance from the Fukushima Daiichi NPP to evacuation locations. It is noted

that after the nuclear accident, the Japanese government issued evacuation orders and defined evacuation zones but did not instruct people where to evacuate. People may have perceived the safe distance from radiation exposure differently. Consequently, some people moved to areas with high levels of radiation within the radiation plume (Yoshida, 2016). Additionally, the paper will discuss the factors that influence the choice of an evacuation location. Specifically, the differences in evacuation location decisions between evacuees with different socio-demographic characteristics, economic statuses, perceived radiation risk, and location of origin will be examined. Moreover, the paper also discusses the reasons for selecting evacuation locations and their distance from the facility to elucidate the possible influence of radiation risk on evacuation patterns. Research location

Figure 2: Map of evacuation zone in August 2011 Source: METI, 2011

In the aftermath of the nuclear accident at the Fukushima Daiichi NPP, an evacuation zone was formed following several evacuation orders issued by the Japanese government. In August 2011, the evacuation zone covered an area of approximately 1,800 km2 in 12 municipalities and consisted of three designated areas: 1) restricted areas (i.e. within 20 km radius from the facility) where all residents were forced to evacuate immediately, 2) evacuation preparation areas (i.e. 20–30 km from the facility) where residents were recommended to remain indoors and ready to evacuate if the conditions of the NPP deteriorated, and 3) deliberate evacuation areas (i.e. beyond 20 km from the NPP but the radiation level is high) where residents were requested to evacuate in a planned manner in approximately 1 month (METI, 2011). Minamisoma City was chosen as the research location because it has the largest number of evacuees among 12 affected municipalities, and it spans over 3 different categories of evacuation areas (Figure 2). These geographical and demographic features

make it possible to take samples that represent different evacuation areas, different motivations for evacuation (i.e. mandatory and voluntary evacuees), and different evacuation statuses (i.e. those who returned and those who did not). More specifically, Minamisoma is a 398.5 km2 urban municipality located north of the Fukushima Daiichi NPP. It is the largest municipality in the affected areas in terms of its land area and the number of evacuees (Table 1). Situated within a 10–40 km radius from the nuclear power plant, Minamisoma City has 3 wards lying in 3 different evacuation areas. The entire Odaka ward and part of the Haramachi ward were in the restricted area where all residents were forced to evacuate (Figure 3). Since July 12, 2016, the evacuation order was lifted in most parts of this area, allowing evacuees to return their homes. An area within a 20– 30 km radius of the NPP and covering most of the Haramachi ward was designated as the evacuation-prepared area where people were required to stay indoors and prepare to evacuate if conditions deteriorated. On September 30, 2011, the evacuation order was lifted in this area. Most of the Kashima ward is situated beyond the 30 km radius where no evacuation instruction was issued (Figure 3). Figure 3: Map of the research location Source: METI, 2011 Restricted Area

Okuma Town Futaba Town Tomioka Town Namie Town Iitate Village Katsurao Village Kawauchi Village Kawamata Town Tamura City Naraha Town Hirono Town Minamisoma City Total

Deliberate Evacuation Area

EvacuationTotal (no. of http://www.meti.go.jp/english/earthquake/nu Prepared Area in persons) clear/roadmap/pdf/evacuation_map_a.pdf) Case of Emergency Approx. 11,500 Approx. 11,500 Approx. 6,900 Approx. 6,900 Approx. 16,000 Approx. 16,000 Approx. 19,600 Approx. 1,300 Approx. 20,900 Approx. 6,200 Approx. 6,200 Approx. 300 Approx. 1,300 Approx. 1,600 Approx. 1,100 Approx. 1,700 Approx. 2,800 Approx. 1,200 Approx. 1,200 Approx. 600 Approx. 4,000 Approx. 4,600 Approx. 7,700 Approx. 10 Approx. 7,710 Approx. 5,400 Approx. 5,400 Approx. 14,300 Approx. 510 Approx. 47,400 Approx. 62,210 Approx. 78,000 Approx. 10,010 Approx. 58,510 Approx. 147,020 Table 1: Number of evacuees from the evacuation zone Source: National Diet of Japan, Chapter 4, page 4, 2012

Regarding evacuation motivation, about 15,000 people were forced to evacuate as their residences were in restricted and deliberate evacuation areas. Another 47,000 people within 20–30 km from the NPP evacuated voluntarily because their houses were out of the mandatory evacuation zone. They were recommended to stay indoors although pregnant women and children were recommended to evacuate (IAEA, 2011a). As of February 2016, about 17,000 people remained evacuated. Of which, 40% evacuated within Minamisoma City, 25% stayed in other municipalities inside the Fukushima prefecture, and 35% were outside the Fukushima prefecture (Table 2). Evacuation destination Inside Minamisoma City

2011-June 3,737

2012-June 6,854

2013-June 7,383

2014-June 7,305

2015-June 7,108

2016-Feb 6,872

In Fukushima Prefecture (except Minamisoma)

10,787

7,459

6,326

5,432

4,711

4,297

In other prefectures

18,545

12,401

9,583

8,149

6,753

6,087

Total

33,069

26,714

23,292

20,886

18,572

17,256

Table 2: Distribution of evacuees from Minamisoma City Source: Minamisoma City Office, 2017

Data and methods The primary method of data collection was a questionnaire survey. The survey targeted evacuees from the nuclear disaster-affected areas who have been involved in any form of evacuation, including voluntary and mandatory evacuation, those who have returned home, and those who remain evacuated. The questionnaire was designed to acquire information about the demographic characteristics of evacuees, their family, occupational and economic status, date of movement to each evacuation destination, duration of staying in each destination, reasons for selecting evacuation locations, comparison of living conditions between evacuation destinations and the location of origin, date of return, and reasons for returning or remaining evacuated. A total of 1,700 questionnaires were randomly distributed to both returned and not yet returned evacuees between May and November 2016. Of which, 460 questionnaires were delivered to returnees through house visits, and meeting them in public events. Of the 195 questionnaires returned, 159 were filled out properly; the response rate was 42%, and 34% were valid). Twelve hundred questionnaires were mailed to evacuees who had not yet returned. Of the 210 questionnaires returned, 130 were valid with sufficient important information, and 80 could not be used for analysis because they omitted key information such as the date of evacuation, evacuation destinations, and reasons for selecting evacuation destinations; the response rate was 17.5%, and about 11% were valid. Among the 289 respondent evacuees, 159 had returned, and 130 had not yet returned. It is noted that at the time of the survey of returned evacuees (May to June 2016), the evacuation order had not been lifted in the Odaka ward (i.e. a former restricted area). All 159 returnees in this survey are voluntary evacuees from Haramachi and Kashima wards. However, in the survey of not yet returned evacuees (October to November 2016), among 130 respondents, 71 people were from the Odaka ward. Therefore, the evacuation patterns of people from the former restricted area (i.e. mandatory evacuees) could still be examined. Characteristics of

Number of

respondents

persons

%

Gender Male

112

39%

Female

177

61%

<=40

48

17%

Age (years old)

41-65

170

60%

>65

71

23%

Permanent

115

40%

Contract-based

44

15%

Self-employed

62

22%

Not employed

64

23%

Mandatory

118

41%

Voluntary

171

59%

Returned

159

55%

Remain evacuated

130

45%

Odaka (10-20 km)

73

25%

Haramachi (20-30 km)

176

61%

Kashima (>30 km)

40

14%

Occupation

Evacuation motivation

Return status

District of Origin

Table 3: Characteristics of the surveyed respondents Source: Data from the questionnaire survey of this research

Data analysis There are different ways to examine the spatial distribution of disaster evacuations. It can be classified by regional boundaries (e.g., inside and outside the Fukushima prefecture as well as in Tohoku, Chubu, Kanto, and Kansai regions and internal or international movement), by locations’ urban characteristics (e.g., urban versus rural locations), and by distance (e.g., short versus long distances from the disaster). This paper will examine the spatial patterns of the Fukushima nuclear accident-induced evacuation based primarily on evacuation distance because the nature of radiation hazards cannot be seen, touched, or tasted. Additionally, the risk of radiation exposure decreases as the distance from the disaster site increases. Evacuation distance is the absolute distance from the Fukushima Daiichi NPP to the location to which an evacuee evacuated. With the location of each evacuation destination provided by respondents in the questionnaires, the distance is measured by ArcGIS. Average evacuation distance, the distance to the furthest location and the distance of the location stayed at the longest will be used to examine the spatial aspects of the evacuees’ evacuation locations. Average evacuation distance of a group of evacuees (representing a demographic or socio-economic characteristic) at a certain time is calculated by the sum of evacuation distances divided by the number of evacuees in the group. The distance of the furthest location is the farthest distance from the NPP among all locations to which evacuees moved. It can be observed that many people have moved to several places. In this survey sample, people evacuated to approximately four different locations on average. It is assumed that the farthest evacuation distance represents their perception of a place that was safe from

radioactive contamination. This will be examined with temporal input to explore when people reached the furthest evacuation destination. The distance of the location stayed at the longest is the one where evacuees stayed for the longest duration among all locations to which they have evacuated. It is assumed that while the selection of furthest evacuation location may have been strongly influenced by the fear of radiation, more factors are believed to be involved in choosing the location where they stayed longest, especially for those engaged in a long-term evacuation. A one-way analysis of variance (ANOVA) and an independent t-test were used to examine the differences in average evacuation distances between different groups of evacuees with different socio-demographic characteristics, economic statuses, locations of origin, and perceptions of radiation risk. Extremely long evacuation distances (i.e. over 1,000 km away from the NPP) from 11 evacuees were not included in the ANOVA and T-test analyses to reduce the noise in the average values of the samples. Cross-tabulation was also used to examine the reasons for selecting evacuation destinations. For this examination, evacuation distances are separated into 4 groups: within 100 km, 100–300 km, 300–500 km, and > 500 km from the NPP. II. RESULTS 2.1. Temporal-spatial patterns of evacuation The spatial pattern of the Fukushima nuclear accident evacuation changed considerably over time. Data from 289 respondents from Minamisoma City illustrate that immediately after the accident, most people evacuated to locations near their home areas (i.e. <100 km from the NPP) for their first movement (Figure 4a). However, soon afterward, most of them continued to move to further distant locations. There was a sharp increase in the number of people moving to locations within a 100–300 km radius of the NPP while the proportion of those taking refuge inside the 100 km radius decreased significantly. At the end of March 2011, approximately 47.4% of the respondents in our sample evacuated to within a 100–300 km radius of the NPP, 44.6% stayed within 100 km, 3.5% stayed within 300–500 km, and 4.5% moved to locations beyond a 500 km radius of the facility. Voluntary evacuees started returning home in early April 2011. As of March 2016, 54.7% of evacuees had returned and 16.3% remained evacuated within a 100 km radius from the NPP while 22.8%, 1.7%, and 4.5% of the respondents remained within 100–300 km, 300–500 km, and beyond a 500 km radius from the nuclear accident site, respectively. It can be observed that the number of evacuees who took refuge in the most distant location (> 500 km) seems most stable. The average evacuation distance of respondents began at approximately 107 km at their first location. This distance then increased significantly within 3 weeks after the accident. The average evacuation distance reached a peak 161 km radius from the NPP in the first week of April 2011 (Figure 4b). After this time, the average distance gradually decreased. It is noted that the average evacuation distance is calculated by the sum of evacuation distances divided by the total number of evacuees at a certain time; those who have returned are excluded from the calculation. Therefore, the decreased evacuation distance indicates that people have gradually moved closer to their home location.

Figure 4a: Spatial distribution of respondents

Figure 4b: Average evacuation distance of respondents

The maps below (Figure 5a,b) illustrate more specifically the geographical patterns of evacuation at two different times: after a short period and 5 years after the accident. Three major features can be captured from these illustrations. First, the distribution of evacuation destinations of respondents at the end of March 2011 is more scattered than in March 2016. Second, during both periods, evacuees were concentrated in short distance locations rather in distant locations. Third, the Tokyo metropolitan region attracted a significant number of evacuees during both periods. At the end of March 2011, Tokyo had attracted about 10% of the respondent evacuees. It ranked second after Fukushima City (14.5%) while Koriyama City and Sendai City followed with 5.6% and 5%, respectively. In March 2016, the proportion of respondents who remained in the Tokyo region was 18.3%.

Figure 5a: Distribution of respondents in March 2011

Figure 5b: Distribution of respondents in March 2016

In the USA’s Three Mile Island nuclear accident in 1979, people evacuated on a voluntary basis; 53% of evacuees returned home one week after the evacuation, and within three weeks after the accident, 98% of evacuees had returned home (Cutter & Barnes, 1982). Three weeks after the Fukushima nuclear accident, 16% of voluntary evacuees from Minamisoma City had returned home (due to no statistical data of evacuees available until May 2011, this value is from the questionnaire survey). This rate is much lower than that of the TMI cases, possibly because of the greater severity of the accident at the Fukushima Daiichi NPP; many evacuees kept moving further in the following months before gradually returning home (Figure 5a). In terms of evacuation distance, evacuees from this survey moved to locations with an average distance of 107 km away from the facility in the first week and 154 km in the third week. This shows the two cases had a similar spatial pattern of evacuation. Compared to the average evacuation distance of evacuees in the TMI accident, 85 miles, which is equivalent to 136 km radius of the disaster site (Zeigler et al., 1981), the average evacuation distance of evacuees from Minamisoma City was a little further. Furthest evacuation location and evacuation location stayed at longest Among the 289 respondents in our sample, 89 people moved to only one place while the remainder moved to more than one place; the average number of evacuation destinations in the samples is 3.8). Where was the furthest evacuation destination, what location did respondents stay at the longest, and when did evacuees reach these locations? When the location

Furthest location

Location stayed at

was reached

longest Number of respondents

%

Number of respondents

%

Immediately after evacuation 36 18.0 5 2.5 End of March 2011 87 43.5 55 27.5 By April 2011 51 25.5 72 36.0 By May 2011 7 3.5 11 5.5 By June 2011 10 5.0 8 4.0 After June 2011 9 4.5 49 24.5 Table 4: Time of moving to the furthest evacuation location and the location stayed at longest

Table 4 above shows the temporal-spatial process of evacuation for evacuees from Minamisoma City. To distinguish the different patterns of reaching the furthest evacuation locations and the location that evacuees stayed at the longest, 89 people who moved to only one place are not included in the table because their only evacuation is considered either the furthest location or the location stayed at the longest. Most evacuees moved to their furthest evacuation location somewhat earlier than they moved to the location where they stayed the longest. Within 3 weeks, 61.5% of the respondents had reached their furthest destination, while 95.5% of respondents reached it within 3.5 months. In comparison, only 30% and 75% of respondents reached the location stayed at the longest in the same periods. In contrast, while only 4.5% of respondents moved to their furthest locations after June 2011, 24.5% of respondents arrived at the location they stayed at the longest in the same period. The difference in the timing of moving to these locations suggests that immediately after the accident, people tended to move to a further location from the affected areas before settling down in the locations with shorter distances for their longest stay. The average distance to the furthest destination is a 207.4 km radius from the NPP while that of the location stayed at the longest is a 176.6 km radius from the NPP. Despite this 30km difference in distance, Figure 7 shows almost identical geographical patterns between the furthest evacuation locations and the evacuation locations stayed at the longest. The spatial distribution of both locations is consistent with the distance decay law as well as the gravity model of migration. The main difference is shown in Table 5; more people stayed within the 100 km radius as their location stayed at the longest compared to that of the furthest evacuation locations (41.2% and 31.2%, respectively). The differences in the proportion of the distribution to other evacuation locations are insignificant. Evacuation location Within 100 km 100–300 km 300–500 km > 500 km

Furthest location

Location stayed at longest

Number of % Number of respondents respondents 90 31.1 119 162 56.1 142 15 5.2 12 22 7.6 16 Table 5: Spatial distribution of evacuation location

% 41.2 49.1 4.2 5.5

In the first 3 weeks, wherein 87% evacuees reached their furthest evacuation destinations, 56% people moved to areas within 100-300 km from the NPP. The average distance of the furthest evacuation destination is 207.4 km. Can this value represent the respondents’ perceived safe distance from the disaster site? It is hard to say because people selected their evacuation destination using many different reasons. Only 9% of respondents mentioned safety from radiation as their primary reason for choosing a certain evacuation destination. Among those who mentioned this, the locations that were perceived as safe from

radiation also vary significantly. Further study is needed to reach a more convincing conclusion on this matter. 2.2. Factors that influence evacuation distance The above analysis has shown the temporal-spatial patterns of the evacuation. Clearly, the spatial feature of the evacuation is dispersed and dynamic over time. An examination of the reasons for selecting evacuation locations is necessary to provide better insights into what factors evacuees considered when selecting evacuation destinations. Table 6 illustrates the reasons for selecting evacuation destinations provided by respondents when answered the open-ended question "Why did you move to that evacuation destination?". REASONS FOR SELECTION OF EVACUATION LOCATION

Having acquaintance s nearby

Stayed in acquaintances' accommodations

Places Instructed/ recommended by government and acquaintances

Safe from radiation 8%

11%

4%

Evacuation shelter/ temporary housing

Accommodations available for lease

Convenient location to access social facilities: schools, shops, transportation

Job-related matters: job relocation, new job, and better job opportunity

Having support from evacuation destination

4%

10%

1%

< = 100 km

13%

20%

29%

> 100–300 km

16%

39%

12%

8%

3%

8%

5%

4%

4%

> 300–500 km

33%

40%

7%

13%

0%

7%

0%

0%

0%

> 500 km

5%

40%

0%

25%

0%

0%

10%

15%

5%

14%

29%

20%

9%

7%

6%

5%

8%

2%

Overall

Table 6: Reasons for selecting evacuation location

Overall, the social network is the most influential factor in selecting evacuation destinations, which was the main reason for 45% of respondents’ destination choices. Of which, 29% selected their evacuation locations because they could stay in acquaintances’ houses, and 14% moved to places near acquaintances. This factor is even more important for those moving to distant locations than those moving to areas near their home (45% and 33%, respectively) although the number of evacuees who moved to distant locations is not significant. It is understandable because, without a social network, evacuees will incur higher costs associated with accommodations and may find it more difficult to adapt to a new living environment and cultural differences when moving far away from their home. The important of human network in deciding a destination for migration has been acknowledged an important factor in the literature when Boyd (1989) found that family and community networks play an important role in facilitating migration to industrial nations and Haug (2008) suggested that social networks have a positive impact on chain migration. Moving to places recommended by the city office or acquaintances is the second most popular reason (20% respondents). After the evacuation order was issued, the local municipality directed residents to evacuation shelters administered in public spaces. It was also recommended that people go to places where local authorities welcomed and provide support to evacuees, for example, Minamisoma City recommended its residents to go to Niigata and Yamagata prefectures because the prefectures welcomed evacuees from the disaster affected areas and provided some supports. Beginning in August 2011, evacuees in the restricted areas were entitled to stay in temporary housing; thousands of them decided to do so. This reason predominantly applies to areas near the home where 29% of evacuees followed the instructions of the municipality, and 11% moved to evacuation shelters and temporary houses; no one moved to the most distant locations for this reason. With reference to the location of origin, this reason was more popular among evacuees from the restricted

area (Odaka Ward) with 27% compared to 15% and 13% of those from the evacuation preparation areas (Haramachi Ward) and outside the evacuation zone (Kashima Ward), respectively. Safe from radiation, certainly, is one of the concern of evacuees when selecting an evacuation destination Although fear of radiation exposure was the most important reasons for evacuation (concerned by 66.3% respondents), for selecting an evacuation destination, people considered many other factors. Radiation safety contributed much less significant (only 9% respondents – 38 people –mentioned safety from radiation as their primary reason for choosing an evacuation destination). In fact, the at the time of the evacuation (all respondents evacuated very shortly after the evacuation orders from the Japanese government – within 3 days after the nuclear accident), the level of radiation has not been measured properly and the risk communication was poorly performed by authorities (Hasegawa, 2013). People acted mainly based on their own judgement of radiation exposure risk without the availability of the official data from the government. Most respondents who selected a destination because of its safety from radiation simply mentioned the safety reason without further explanation of why it is safe. As the distance from the disaster site increased, the respondents’ sense of safety seems increased; 8% felt safe near their home areas compared to 25% in the most distant locations. However, this figure indicates that there are widely different perceptions of how far is safe from radiation as near-home areas and areas within 100–300 km were also perceived as safe from radiation by 8% of respondents each. Eight percent of evacuees selected evacuation locations because of job matters of their own or of their spouses such as returning to their job in the home area, job relocation, and job opportunities. It is important to note that job-related reasons are more important for respondents engaged in permanent jobs and those selecting locations a short distance away (14%). Except for the 15% of evacuees dispatched to most distant locations because of job obligations, the job issue is more important in the shorter distance locations (10% in areas near home, 4% in the 100–300 km radius, and 0% in the 300–500 km radius). In addition to the above reasons, evacuees also considered the convenience to social facilities such as to school for children, to shops and transportation (5% respondents). The consideration of school for children applied particularly to parents who were from the restricted areas and those who determined a long evacuation period. Some people sought a location where social services such as shops and banks are available because immediately after the triple disaster, those services were temporarily terminated in large affected areas. Some evacuees searched a location where they can easily access to the public transportation for further evacuation if the situation at the nuclear facility getting worse or to go back to their home location. A small proportion of respondents considered the availability of supports offered by the local government at the evacuation destination, particularly accommodation, job and financial supports which helped them to easier to adapt with the refugees’ lives. 2.3. Association between socio-demographic characteristics of evacuees and evacuation destination (distance) The above temporal-spatial features of the evacuation and the reasons for selecting different evacuation locations have been illustrated. Another question is whether people with different characteristics act differently in choosing their evacuation destination. The following sections will examine possible associations between socio-demographic characteristics, economic and family statuses of evacuees, and their evacuation distance. The

extreme values of evacuation distance (over 1,000 km) are removed to minimize the noise on the average values when using an ANOVA and a T-test for analysis. 2.3.1. Fear of radiation and evacuation distance One’s perception of the hazard is recognized as a factor that strongly influences the decision to evacuate in natural disasters (Nozawa et al., 2008; Riad et al., 1999) as well as being a determinant of returning home after a nuclear disaster (Orita et al., 2013). No research has examined the association between radiation risk perception and evacuation distance. In nuclear accident evacuations, it is expected that people who express more fear of radioactive contamination will move to more distant locations than those who do not. In this survey, people were asked a semi-open-ended question: “What were the reasons for your evacuation?” to which respondents could list any possible reasons that motivated them to leave their home. Two-thirds of respondents expressed “fear of radiation exposure” as one of the driving motivations behind their evacuation. It is followed by “forced to evacuate” (46.6%), “evacuated with family” (33.0%), and “living conditions deteriorated in home location” (29%). This illustrates that fear of radiation exposure is the most influential reason for people to evacuate.

Figure 6: Temporal-spatial distribution of evacuees by perception of radiation risk

Figure 6 shows that immediately after the accident, those who expressed fear of radiation were more likely to migrate further. However, over the longer time scale, there is no difference in evacuation distance between those expressed fear of radiation as a reason for evacuation and those who did not evacuate because of a fear of radiation. When examining the average evacuation distances of these two groups in different time periods, the T-test results illustrate that in late March 2011 (two weeks after the accident), the evacuation distance of these two groups is statistically different (t(274) = 5.7, p = 0.007) with the average evacuation distance of those expressed fear of radiation as a main reasons for evacuation is 35 km farther than those did not express this fear (151.7 km and 116.7 km, respectively).

Distance of furthest evacuation location (km) Distance of the location stayed at longest (km)

Fear of radioactive contamination as the main reason for evacuating No

N

Mean

Std. Deviation

Std. Error Mean

91

164.5

131.6

13.7

185

180.4

123.1

9.0

No

91

149.2

134.0

14.0

Yes

185

145.3

104.4

7.6

Yes

Table 7: Evacuation distances of evacuees according to fear expressed about radiation

When examining the differences in the furthest evacuation distances between those expressing fear of radiation as a main reasons for evacuation and those who did not express it, the T-test result suggests that although those who expressed a fear of radiation tended to move further to their furthest evacuation location (M = 180.4 km) than those who did not (M = 164.5 km) (Table 7), the difference is not statistically significant (t(274) = 0.98, p = 0.328). Similarly, there is no statistical difference between the two groups in terms of the locations that evacuees stayed at longest (t(274) = 4.25, p=0.79). These results indicate that the fear of radioactive contamination has an influential impact on the decision to evacuate and on the evacuation distance soon (2–3 weeks) after the nuclear accident, and those who expressed fear of radiation tended to move a farther distance. 2.3.2. Demographic characteristics of evacuees and evacuation distance Gender and evacuation distance Gender has been recognized as a common predictor in evacuation behavior; females are more likely to evacuate than males in natural disasters (Elliott & Pais, 2006; Riad et al., 1999; Smith & McCarty, 2009). In the Fukushima nuclear accident, the statistical data shows that the rate of evacuation is slightly higher among females than males, and the return rate of females is slightly lower than that of males, at 71% and 75%, respectively (Minamisoma City Office, 2017). However, despite the slight differences in evacuation and return rates, there is no difference between males and females in evacuation distance. Figure 7 below illustrates almost the same temporal-spatial evacuation patterns between both sexes.

Figure 7: Temporal-spatial distribution of evacuees by gender

In terms of the distance of the furthest evacuation location, the mean values of males and females are almost the same at 170 km and 178 km from the NPP, respectively (Table 8). Regarding the distance of the location stayed at longest, although there is an 18 km difference between males (M = 140, SD = 137) and females (M =155, SD = 119), the difference is not statistically significant (t(234) = -0.5, p = 0.617). The results suggest that there is no association between gender and evacuation distance in the Fukushima nuclear accident evacuation.

The distance of the furthest evacuation location (km) The distance of the location stayed at the longest (km)

Gender Male

N

Mean

Std. Deviation

Std. Error Mean

106

170.2

120.5

11.7

172

177.9

129.1

9.8

106

132.0

105.3

10.2

172

155.5

119.3

9.1

Female

Male Female

Table 8: Evacuation distances of evacuees by gender

Age of evacuees and evacuation distance

Figure 8: Temporal-spatial distribution of evacuees by ages

Figure 8 above shows the temporal-spatial features of the Fukushima evacuation among different age groups. The average evacuation distance of the eldest group (> 65 years of age) is higher than that of the youngest age group most of the time. Although there were almost no different evacuation features between all groups within 3 weeks after the accident, beginning in April 2011, the average evacuation distance of the eldest group is consistently higher than that of the youngest group. However, an ANOVA of the average evacuation distance between age groups at each individual time shows that the differences in evacuation distances are not statistically significant. Regarding the furthest evacuation locations, the distance seems to proportionately increase with age: 165 km, 170 km, and 191 km for the youngest group aged 41–65 and the eldest group, respectively. Similarly, the average distance of the locations that evacuees stayed at the longest of the eldest group is also farthest among these 3 age groups (Table 9). However, the ANOVA results reveal that the differences are not statistically significant. In fact, statistical data of evacuees from Minamisoma City reveal that the evacuation rate of the eldest group (> 65 years of age) is the lowest among the three groups; their higher average evacuation distance compared to that of the youngest age group remains unknown. Further study is necessary to have a better explanation of these results.

Age

N

Mean

Std. Deviation

Std. Error Mean

The distance of the furthest evacuation location (km)

< = 40

48

165.1

15.7

133.3

41–65

163

170.8

9.9

151.1

> 65

67

192.1

16.2

159.6

The distance of the location stayed at the longest (km)

< = 40

48

141.3

14.6

111.9

163

140.0

9.0

122.1

67

166.2

14.6

136.9

41–65 > 65

Table 9: Evacuation distances of evacuees by age

Parents of young children and evacuation distance

Figure 9: Temporal-spatial distribution of evacuees by having young children

Only 35 respondents in the samples had children under ten years of age at the time of the accident. Figure 9 above shows that until July 2011, those who had children under 10 years of age tended to move farther than those did not. Afterward, the spatial distribution of these both groups of evacuees are not consistently different. Independent sample T-tests of the average evacuation distances between the two groups at different times until March 2016 reveals that although the evacuation distances of those who had young children tended to be shorter until July 2011, only in the first evacuation location are the differences in evacuation distance between the two groups statistically significant (t(276) = 2.338, p =0.02).

N The distance of the furthest evacuation location (km) The distance of the longest stayed location (km)

Not having young children Having young children Not having young children Having young children

Mean

Std. Deviation

Std. Error Mean

243

179.7

128.9

8.2

35

142.2

96.3

16.2

243

151.4

118.9

7.6

35

113.0

70.8

11.9

Table 10: Evacuation distances of evacuees by having young children

The distances of the furthest evacuation destination, as well as the location, stayed at the longest among those having young children are also shorter than among those who do not have young children (Table 10). The test results from independent sample T-tests suggest that there is no statistically significant difference in mean distance of the furthest evacuation locations between the two groups. However, the difference in the mean distance of the location stayed at the longest was found to be statistically significant (t(276) = 2.709, p = 0.009). These results suggest that evacuees with young children tended to evacuate to closer destinations immediately after the nuclear accident and then remained in closer locations for longer durations.

Because young children are more sensitive to radiation (WHO, 2016), it is expected that evacuees with young children would be more cautious about the health risk of ionizing radiation, and they would, therefore, evacuate longer distances. However, the findings from this survey suggest the opposite; 68% of respondents with young children evacuated within a 100 km radius from the NPP compared to 50% of those without young children. Additionally, 12% of respondents with young children decided to evacuate a short distance because it was convenient to social facilities (mainly indicated by school accessibility) while only 3% of those without young children selected this area for the same reason (but mainly focused on the availability of commodities and transportation). Information collected from semi-structured interviews also reveals that a considerable number of voluntary evacuees decided to return so their children could resume schooling as the academic year in Japan starts in April. For mandatory evacuees in the restricted areas, children’s schools were relocated to adjacent areas. The average distance of the location stayed at the longest of parents of young children––113 km from the NPP––also indicates that many people moved to other municipalities inside Fukushima prefecture rather than distant locations because the school environment is not much different from that of home location. Occupational status and evacuation distance

Figure 10: Spatial distribution of evacuees by occupation

Regarding occupation, although no evidence of an association between occupation and evacuation behavior has been found in the literature, the differences in evacuation and return rates between working age groups and non-working age groups in Minamisoma City suggest that an association may exist. To examine the possible association between the occupational status of evacuees and their evacuation destinations, jobs of evacuees at the time of the nuclear accident were divided into 4 groups: permanent job (full-time jobs related to government officials, teachers, doctors, nurses); contract-based (part-time jobs, contractbased staff); self-managed (business owners, farmers, fishermen); and unemployed (houseworkers, retirees, students, and other unemployed persons). Figure 10 shows considerable differences in evacuation locations between two occupational groups: those with permanent jobs and those not employed. A significantly higher proportion (60%) of evacuees engaged in

permanent jobs evacuated to locations a short distance away within a 100 km radius of the NPP than those in the unemployed group (42%). In contrast, 8% of unemployed respondents evacuated beyond 500 km whereas only 2% of respondents with permanent jobs moved to this area because of dispatching by their employer.

Occupation The distance of the furthest evacuation location (km)

The distance of the location stayed at the longest (km)

N

Mean

Std. Deviation

Std. Error Mean

Permanent

112

149.8

107.7

10.1

Contract-based

42

163.9

112.9

17.4

Self-employed

60

183.5

137.9

17.8

Unemployed

60

215.5

142.2

18.3

Permanent

112

124.6

100.3

9.4

42

137.6

103.0

15.8

Self-employed

60

157.4

124.9

16.1

Unemployed

60

177.5

125.9

16.2

Contract-based

Table 11: Evacuation distances by evacuees’ occupation

Table 11 shows the differences in average evacuation distances between different occupational groups. The ANOVA results indicate the differences in the distances of the furthest evacuation locations between those engaged in permanent jobs and those who were unemployed are statistically significant (F(3,270) = 3.895, p = 0.009). A Turkey post hoc test again confirms the distance of the furthest evacuation destination of the unemployed group was significantly higher than that of the permanent occupation group (149 km and 215 km, p = 0.014). The ANOVA result also indicates the differences in the average distances of the location stayed at the longest between evacuees who were engaged in permanent jobs and those who did not. The average evacuation distance of the former group is 52.9 km shorter than that of the latter (p = 0.035). The reason for these differences is believed to be mainly job obligations because in the shorter distance locations, job issues (mainly job obligations) have a higher impact on the decision of selecting evacuation destinations than that of further distant locations (10% in areas near home, 4% in the 100–300 km radius, and 0% in the 300–500 km radius). Of the respondents with permanent jobs, 14% evacuated within a 100 km radius of the NPP because of job-related matters while only 3% of the unemployed evacuees moved to this area for the same reason. The semi-structured interviews also suggest that people engaged in permanent jobs were less likely to voluntarily evacuate than those who were unemployed. Many evacuees in this group remained in their home areas or evacuated to nearby locations temporarily and then returned very quickly when their work resumed after the accident whereas those who were unemployed were free to voluntarily evacuate. Educational levels of evacuees and evacuation distance In the literature on disaster migration, educational level has been recognized as a factor that influences evacuation behavior. However, the influences of this factor are not uniform. While some studies found that a higher educational background is positively associated with the decision to evacuate (Hasan et al., 2011; Medina & Moraca, 2016; Thiede & Brown, 2013), others reported that it was negatively correlated (Paul, 2012; Reininger et al., 2013). In nuclear accident studied, no research has examined the possible association

between educational background and evacuation location. Some may assume that those having higher education may have better knowledge or better access to information related to the risk of radiation exposure, and may, therefore, take refuge earlier and at a further distance. Some of them stayed in public housing or in leased accommodation close to their work place in home area. Educational Level The distance of the furthest evacuation location (km)

The distance of the evacuation location stayed at the longest (km)

N

Mean

Std. Deviation

Std. Error Mean

Junior High School High School

23

188.5

130.2

27.1

128

178.6

128.5

11.3

College

64

160.0

120.6

15.0

University

63

177.7

125.0

15.7

23

158.4

109.5

22.8

Junior High School High School

128

142.0

111.0

9.8

College

64

150.1

122.0

15.2

University

63

147.9

117.9

14.8

Table 12: Evacuation distances of evacuees by educational level

Table 12 shows the differences in the evacuation distances of groups with different educational backgrounds. However, the differences suggest an inconsistent propensity between evacuation distance and the respondents’ educational levels. The ANOVA test also reports no statistical evidence of the association between evacuation distance and the educational level of evacuees for the furthest evacuation distance (F(3,274) = 0.431, p = 0.747) or for the distance of the location stated at the longest (F(3,274) = 0.172, p = 0.915). These statistical results suggest that educational level has no influence on the evacuation distance of evacuees. 2.3.2. Evacuation distance of evacuees by the location of origin (proximity to the NPP) The association between proximity to the nuclear accident site and evacuation behavior has been recognized. In the TMI case, the proximity of the nuclear power plant is one of a number of strong influential factors on evacuation behavior found when Johnson (1986) showed that people who lived closer (i.e. within 5 miles) to the facility were more likely to evacuate. However, in terms of evacuation distance, Zeigler et al. (1981) found that although people living closer to the facility left their homes earlier, they evacuated a shorter distance than individuals living further away. The same propensity was observed by Cutter & Barnes (1982). Two explanations for this phenomenon were offered. First, people living closer to the plant were likely to be most concerned about their homes and properties (Zeigler et al., 1981). Second, those living further from the accident site tended to overestimate the magnitude of the threat than those living closer to the hazard area (Cutter & Barnes, 1982). In the case of the Fukushima nuclear accident, the data of this survey shows that in the first month after the accident, the evacuation distance of evacuees from the Odaka ward (approximately 10–20 km from the NPP), Haramachi ward (approximately 20–30 km), and Kashima ward (approximately 30–40 km) were relatively similar regardless of their proximity to the nuclear site. However, the distance of the furthest evacuation location of evacuees from Kashima ward is less than those from the Odaka and Haramachi wards (Table 13). It is understandable because Kashima Ward is located outside the evacuation zone. Most evacuees from this ward evacuated for a short period of time to locations a shorter distance away.

ANOVA results also confirm no statistical differences in the furthest evacuation distance between evacuees from different wards of origin (F(3,275) = 0.385, p = 0.681). However, statistical evidence was found suggesting the association between the location of origin and the distance of the location stayed at the longest (F(2,275) = 5.96, p = 0.003). The Turkey post hoc test again confirms that the difference in the distances of the location stayed at the longest between Odaka and Haramachi wards are statistically significant (mean difference = 55.4 km, p = 0.000). These results suggest that people living closer to the NPP (the Odaka ward) tended to evacuate and stay at a shorter distance away than those from Haramachi and Kashima wards. As those from the Odaka ward are mandatory evacuees and those from Haramachi and Kashima wards are voluntary evacuees, these results also illustrate the differences in evacuation destination regarding different evacuation motivations (forced and voluntary). Ward of Origin The distance of the furthest evacuation location (km)

The distance of the location stayed at the longest (km)

Odaka (10–20 km) Haramachi (20– 30 km) Kashima (> 30– 40 km) Odaka (10–20 km) Haramachi (20– 30 km) Kashima (> 30– 40 km)

N

Mean

Std. Deviation

Std. Error Mean

69

168.7

123.6

14.8

169

180.1

126.4

9.7

40

163.8

128.4

20.3

69

107.7

85.6

10.3

169

163.1

122.7

9.4

40

143.6

108.4

17.1

Table 13: Evacuation distances of evacuees by the location of origin

Regarding the proximity of home location to the NPP, the spatial pattern of the evacuation caused by the Fukushima nuclear accident shares a similar feature with the TMI case although the reason is different. As the Odaka ward was designated as a restricted area for more than five years, residents from this ward were aware of the long-term displacement. Therefore, a considerable proportion of this population decided to stay in temporary housing located in near to their home location. This could help them reduce living expenses, and it is more convenient for them to temporarily visit their properties in the home area for cleanup and maintenance. This suggests that the appropriate policy for providing housing supports for long-term evacuees is better outside the evacuation area but not too far from evacuees’ home areas. 2.3.3. Evacuation distance of evacuees by economic status People were asked to self-assess their economic status at the time of the accident and select an answer with three possibilities: good economic status, average economic status, and disadvantaged economic status. Of the respondents, 137 (50%) assessed their economic condition as good, 118 (43%) as average, and 19 (7%) as having a disadvantaged economic status. Table 14 shows that people with a disadvantaged economic status tend to evacuate shorter distances than those with better economic conditions. However, ANOVA results indicate that the differences are not statistically significant for either the distance of the furthest evacuation location (F(2,271) = 1.925, p = 0.148) or the location stayed at the longest (F(2,271) = 1.784, p = 0.170).

Economic Status

N

Mean

Std. Deviation

Std. Error Mean

The distance of the furthest evacuation location (km)

Good

137

184.5

136.3

11.6

Average

118

171.1

120.7

11.1

Disadvantaged

19

125.3

61.9

14.2

The distance of the location stayed at the longest (km)

Good

137

155.4

127.4

10.8

118

141.7

105.3

9.6

19

104.5

58.0

13.3

Average Disadvantaged

Table 14: Evacuation distances of evacuees by economic status

In disaster migration literature, economic status was found to be associated with evacuation behavior. Studies about Hurricane Katrina and Hurricane Ivan reveal that people with a higher economic status are more likely to evacuate than those with a disadvantaged economic status (Elliott & Pais, 2006; Hasan et al., 2011). No study has examined the association between economic status and where they moved to in either natural or nuclear disasters. Although the results from this survey statistically indicate no association between the economic status of evacuees and their evacuation distance, the number of respondents with a disadvantaged economic status is relatively small, only 19 cases. Therefore, further investigation with a larger sample size may produce a more generalizable result. III. DISCUSSIONS AND CONCLUSION The results presented in this paper have elucidated the temporal-spatial features of the Fukushima nuclear accident evacuation as well as factors that impact the decision of evacuation location. Geographical features of evacuation associated with the accident Two main features can be pointed out regarding the patterns of the Fukushima nuclear accident evacuation. First, the spatial distribution of the nuclear accident evacuation is generally consistent with the Law of Migration, which commonly applies to all forms of migration. More people evacuated to areas a shorter distance away and fewer to areas a longer distance away. However, evacuees increased their evacuation distance soon period after the accident. The average evacuation distance of the whole sample increased significantly in the first three weeks and reached its peak early in April 2011. This is also the time most evacuees moved to their furthest evacuation locations. Afterward, the evacuation distance started to gradually decrease. By the end of June 2011, most people who remained evacuated reached the locations that they stayed at the longest. The earlier timing and longer distance of the furthest evacuation locations compared to that of the location stayed at the longest suggest that the fear of radiation exposure may have a strong influence on evacuation distance immediately and soon after a nuclear accident. Second, the spatial distribution of the evacuation is also consistent with the gravity model of migration wherein the number of evacuees is proportional to the size of destinations. It is observed that a significant number of evacuees were attracted to major urban cities, especially the Tokyo metropolitan region. Major prefectural cities such as Fukushima, Niigata, Sendai, and Yamagata also received more evacuees than their neighboring municipalities the same distance away at all times. It can be said that the spatial features of the Fukushima nuclear accident evacuation share common patterns with other kinds of disaster migration. It is difficult to properly compare

these features with those shown in previous nuclear accidents because there is a lack of research about the migration in the Chernobyl case and the different nature of evacuation motivation in the TMI case where only voluntary evacuation has taken place and for a short period of time. The average evacuation distance of respondents in this survey was approximately 107 km and 154 km from the accident site one week and three weeks after the nuclear accident, respectively. In the TMI nuclear accident, the average evacuation distance was 136 km (85 miles) from the reactor within 3 weeks (Zeigler et al., 1981). The evacuation distance during the same period between these two nuclear disasters seems quite similar. However, it is again difficult to properly compare them because the two events are different in the level of severity, and the geographical features of the two disaster sites are different. Since the fear of radiation exposure shows its statistically strong influence in the choices of evacuation distances in the first three weeks after the accident, the factual distance of evacuation at this time may represent their perceived safety zone. Data from the survey of this study reveals that 50% of total respondents moved to areas located 60–180 km from the nuclear facility, with an average evacuation distance of 154 km. Therefore, this distance can be considered the safe distance perceived by evacuees from the Fukushima nuclear accident-affected areas. Compared to the TMI nuclear accident where the perceived safety area was between 72.4 and 144.8 km (45–90 miles) since 50% of respondents moved to these areas (Zeigler et al., 1981), the safety area perceived by evacuees from the Fukushima nuclear accident seems farther and wider in its boundaries. This can possibly be due to the Fukushima accident’s higher severity as well as the higher degree of uncertainty or ambiguity about the risk of radiation exposure and the duration of evacuation among evacuees of the Fukushima accident. Reasons for evacuation destination selection Social networks are the most influential factor for evacuees in deciding their evacuation destinations, especially for their first evacuation location immediately after the nuclear accident, with approximately 51% of respondents moving to places where they have family members or friends. Of which, about 28% stayed in acquaintances' accommodations. It is understandable because the evacuation took place suddenly and was unplanned; many people could not take any belongings with them, and many thought the evacuation would be temporary. Social networks are not only important during short periods after an accident. It was the reason for 43% evacuation destination choices overall. Although the importance of social networks in migration has been reported in the literature (Warner et al., 2009), in the Fukushima nuclear accident evacuation, this factor seems more prominent compared to other factors that influenced the choice of evacuation destinations. Moving to locations recommended by the local government or acquaintances is the second most important reason for evacuation destination choices. This reason again applies to the early phase of the evacuation and mainly to short distant locations where evacuees were instructed to move to evacuation shelters or public spaces in their home municipality immediate after the nuclear accident. Many evacuees were also recommended to go to Niigata and Yamagata prefectures because they welcomed the evacuees as a repayment of the support that the Fukushima prefecture offered their residents in a previous disaster. Among the respondents in this study, safety from radiation exposure was not a common reason for choosing evacuation destinations since only 9% of destinations were chosen for this reason. It was observed that choosing a location that is safe from radiation

exposure was more common soon after the accident than in later periods. The perception of how far away is safe is also not clearly perceived by evacuees. Although it seems that the proportion of respondents who moved to more distant evacuation locations because the likelihood of being safe from radiation is higher than moving to closer locations, it is not consistent; 9 respondents moved to the location from 54 km to 70 km from the NPP because they thought these places are safe from radiation exposure. The consideration of safety from radiation exposure in the early period of the evacuation as well as the widely diverse perception of the safety locations reflect the vagueness of the perceived safety distance mentioned above. Besides the three main factors involved in selecting evacuation locations, job-related matters, particularly continuing a job at the home location, the availability of accommodations, and the convenience of access to schools, shops, and transportation are other reasons that shape evacuation destination choices. It is noted that economic factors play a small role in determining evacuation destinations in the Fukushima nuclear accident, except for very few respondents who mentioned that they moved to a location because of employment opportunities. The main reason may be that evacuees from the Fukushima nuclear accident-affected areas received financial compensation for mental anguish and economic losses as well as housing subsidies (OECD, 2012). In this study, this factor has not been examined due to insufficient information collected from the questionnaire. Socio-demographic characteristics of evacuees and the evacuation destinations Evacuees with different socio-demographic characteristics illustrate relatively different evacuation patterns, particularly regarding evacuation destinations. The paper found that evacuees whose home location was in the restricted areas, were engaged in a permanent job, and had young children at the time of the nuclear accident tended to evacuate to closer evacuation locations. The reasons are not related to the perception of radiation exposure but more about staying in temporary houses near home areas, staying close to home for the continuation of a job, and children' school matters. No statistical evidence has been found regarding the association between the age, gender, and educational or economic status of evacuees and the evacuation destination. The paper also found that the perceived risk of radiation exposure only has an impact on selecting evacuation destinations in the short period immediately after the nuclear accident as those who expressed a fear of radiation exposure as the main reason for evacuating tended to move to further distant locations than those who evacuated primarily because of other reasons. There was no evidence of the influence of perceived radiation risk on the evacuation destination in later periods of the evacuation. This finding is also supported by the timing of reaching the furthest evacuation locations in the same period of evacuation. It is difficult to compare the impacts of perceived hazard risk on evacuation destinations after the Fukushima nuclear accident with previous disaster events because although the perceived risk of the hazard plays a crucial role in evacuation decisions (Nozawa et al., 2008; Perry & Lindell, 1991; Riad et al., 1999), no observation about the impacts of perceived risk of the hazard on the evacuation destination has been reported in the literature. In the TMI nuclear accident, the impacts of the perception of radiation exposure risk and the distance of evacuation distance have also not been examined. In conclusion, this paper provides additional empirical evidence to elucidate the temporal-spatial features of evacuation after a nuclear accident. It suggests that a nuclear

accident evacuation shares major spatial aspects with other kinds of disaster evacuation including natural and technological disasters. The results also point to the unique temporalspatial interaction of the evacuation in the early phase of the aftermath when people tried to increase their distance from the NPP and reach their furthest evacuation distance due to the influence of the fear of radiation exposure. The paper also provides a better understanding of the factors that influence evacuation distances. Social networks, recommendations from local governments and acquaintances, and job-related matters are actors that influence the decision of evacuation. It suggests that the perception of radiation exposure significantly influences evacuation decisions only in the short period after a nuclear accident. In the longer term, it shows no impact. As financial issues are believed to have a significant influence on evacuation patterns, it is recommended that further research should focus on examining how compensation and housing subsidies received by evacuees from the Fukushima nuclear accident affected their chosen evacuation locations. There are several limitations in this study. First, the survey was conducted five years after the nuclear accident and when evacuees started their evacuation. Information collected from the questionnaire survey is based on the memories of respondents. Therefore, a relatively large number of returned questionnaires did not properly answer all questions. They are therefore excluded from the analysis. Second, the number of respondents in the sample is relatively small compared to the research population although 289 respondents represent all characteristics of the research population overall. Third, the response rate of the evacuees who remained evacuated is low. This may indicate that they were not interested in the survey because they have left their home for a long period, and many may not intend to return. Some even expressed in the responded questionnaires that they have been surveyed several times before and felt tired with answering the questionnaire. In addition, due to the privacy laws, the questionnaires were enclosed in Minamisoma City office’s information flyers (which they post to evacuees who remain evacuated once a month) posted to evacuees. The author could not check whether or not the questionnaires have been received by evacuees. Finally, information related to the motivation of evacuation (i.e. mandatory or voluntary) provided by respondents seems inconsistent with the classification criteria provided by the Japanese government when comparing their home locations to the evacuation zone. Some people whose houses were in the evacuation preparation areas (20–30 km) answered that they were forced to evacuate. Similarly, information about compensation and housing support received by evacuees is either missing or inconsistent with eligibility criteria issued by the Japanese government. This makes the examination of financial factors’ influence on the evacuation features of evacuees impossible.

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