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Reconstruction following the 2011 Tohoku earthquake tsunami: Case study of Otsuchi Town in Iwate prefecture, Japan

  • June 2015
DOI:10.1016/B978-0-12-801060-0.00029-0
  • In book: Handbook of Coastal Disaster Mitigation for Engineers and Planners (pp.615-630)
  • Edition: 1st
  • Publisher: Elsevier
  • Editors: Miguel Esteban, Hiroshi Takagi, Tomoya Shibayama
Authors:
Miguel Esteban at Waseda University
Miguel Esteban
Motoharu Onuki
Motoharu Onuki
Motoharu Onuki
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Izumi Ikeda
Izumi Ikeda
Izumi Ikeda
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Tomohiro Akiyama at Kobe Institute of Computing
Tomohiro Akiyama
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Abstract and Figures

The 2011 Tohoku Earthquake tsunami caused great devastation throughout the NorthEastern coast of Japan. Following the disaster important reconstruction efforts are currently underway to improve the safety and resilience of coastal communities against future events. To do so the government is investing considerable resources in the creation of a true modern multi-layer safety system, involving reclassifying coastal areas into " Disaster Hazard Areas " where only businesses and public use areas are allowed, and residential areas where people should live. These residential areas are being elevated throughout the region, theoretically ensuring that people living in them should be safer in the case coastal defences are overcome by a tsunami in the future. Important efforts are also being made to promote cultural awareness about the need to evacuate and to improve evacuation routes. The present chapter will discuss various reconstruction issues, including the ever-present dilemma inherent to any disaster reconstruction process were the need to improve disaster resilience is confronted with the desires of survivors to rebuild their houses and livelihoods as quickly as possible. The authors will use Otsuchi Town in Iwate prefecture as a case study, as this was one of the settlements worst hit by the disaster that can serve to highlight the particular socio-economical and demographic challenges facing the region.
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RECONSTRUCTION FOLLOWING THE 2011 TOHOKU EARTHQUAKE
TSUNAMI: CASE STUDY OF OTSUCHI TOWN IN IWATE PREFECTURE,
JAPAN
M. Esteban
1
, M. Onuki, I. Ikeda, T. Akiyama
ABSTRACT:
The 2011 Tohoku Earthquake tsunami caused great devastation throughout the North-
Eastern coast of Japan. Following the disaster important reconstruction efforts are currently
underway to improve the safety and resilience of coastal communities against future events.
To do so the government is investing considerable resources in the creation of a true
modern multi-layer safety system, involving reclassifying coastal areas into “Disaster
Hazard Areas” where only businesses and public use areas are allowed, and residential
areas where people should live. These residential areas are being elevated throughout the
region, theoretically ensuring that people living in them should be safer in the case coastal
defences are overcome by a tsunami in the future. Important efforts are also being made to
promote cultural awareness about the need to evacuate and to improve evacuation routes.
The present chapter will discuss various reconstruction issues, including the ever-present
dilemma inherent to any disaster reconstruction process were the need to improve disaster
resilience is confronted with the desires of survivors to rebuild their houses and livelihoods
as quickly as possible. The authors will use Otsuchi Town in Iwate prefecture as a case
study, as this was one of the settlements worst hit by the disaster that can serve to highlight
the particular socio-economical and demographic challenges facing the region.
1
Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8563, Japan
Fig. 6. Ongoing civil engineering works to elevate the downtown area of Machikata in
Otsuchi Town (September 2014)
CONCLUSIONS
The 2011 tsunami has fundamentally altered the Coastal Disaster Management philosophy
of Japan in general, and the Sanriku coastline in particular. At the heart of this change are
very important philosophical considerations, regarding whether hard or soft types of
tsunami counter-measures should be preferred, and the impact that these have on the beauty
of an area, the feeling that local inhabitants have about them, and the need to defend from
the frequent hazards that strike the coastline.
Prior to 2011, the Sanriku coastline boosted one of the highest levels of awareness against
tsunamis (Esteban et al., 2013, Chapter 11), and this event has further increased this
awareness. What is more, the national and prefectural governments are making major
financial investments to improve all layers of defence, and create a truly modern multi-
layered defence system. To do so, important adjustments are being made to land usage, by
reclassifying coastal areas into “Disaster Hazard Areas” where only businesses and public
use areas are allowed, and residential areas where people should live. These residential
areas are being elevated throughout the region, theoretically ensuring that people living in
them should be safer in case that layer 1 coastal defences are overcome by a tsunami.
Important efforts are also being made to promote cultural awareness about the need to
evacuate, and to improve evacuation routes. The present chapter also highlighted the
problems inherent in such ambitious rebuilding efforts. Essentially, in reconstruction there
is an ever-present dilemma were the need to improve disaster resilience is confronted with
the desires of survivors to rebuild their houses and livelihoods as quickly as possible (see
also Chapter 27). Many of the survivors are currently living in temporary shelters, a
situation which is far from ideal, and clearly wish to return to where they once lived.
Finally, reconstruction efforts must also face the demographic reality of the area. Many of
the towns were already facing rapid population aging and decline before the 2011 event,
which served as a further population decrease catalyst. As a result, it is believed that
probably the population of many of the smaller coastal towns, such as Otsuchi, might have
halved as a consequence of the disaster. For the area to sustainably develop in the future it
will also be necessary to manage this population decline, which would otherwise eventually
result in a huge waste of reconstruction resources.
Acknowledgements
Graduate Programme in Sustainability Science Global Leadership Initiative (GPSS-GLI,
The University of Tokyo).
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Supplementary resource (1)

30-Ch29 Esteban reconstruction Tohoku
Data
October 2017
Miguel Esteban · Motoharu Onuki · Izumi Ikeda · Tomohiro Akiyama
... Evidently, the level of tsunami awareness increased significantly after that amongst the population of Indonesia, as all respondents in the present study knew the dangers of tsunami, and 83% anticipated that a tsunami could take place following an earthquake. Such high levels of awareness that a tsunami could follow an earthquake have also been highlighted in the other places at risk [9,34], though the percentage of respondents answering this (83%) exceeds that (55%) reported for the 2011 Tohoku Earthquake and Tsunami [11]. Considering that few respondents in the present study felt that the information provided by the authorities had been enough (and many had not participated in evacuation drills), the high level of awareness could be the result of oral transmission of prior events to new generations, TV footage and associated media coverage (including the extreme devastation caused by events like the 2004 Indian Ocean Tsunami or the 2011 Tohoku Earthquake and Tsunami) rather than official efforts to disseminate information about tsunami hazards. ...
... 50% of respondents answered that they decided to evacuate due to feeling the ground shaking, which is similar to that reported in previous events (around 60% and 45% did so for the 2010 Chilean [34] and 2011 Tohoku Earthquake and Tsunami [11], respectively). Given the shorter arrival time of submarine landslide tsunamis, it is necessary to increase awareness so that more people evacuate immediately after an earthquake, especially in coastal areas that are at risk of being hit by this type of tsunami event. ...
... In addition, disaster risk managers in Palu City and Donggala Regency must seek to reduce the evacuation time for vulnerable people, as the results clearly showed that female and older people took longer to reach safe places. This can be done through multi-layer safety measures, where the locations where vulnerable groups undertake most of their daily activities is located away from the most at risk areas (such as by placing hospitals and schools on elevated ground, [34]. ...
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On September 28, 2018 significant tsunami waves, which are considered to have been generated by submarine landslides, struck the shorelines of Central Sulawesi, Indonesia. One month after the event, the authors conducted a questionnaire survey of the affected areas (Donggala Regency and Palu City) to collect information on the evacuation behaviour and tsunami awareness of local residents. In the present study, in addition to summarising the overall trend of the survey results using descriptive statistics, a chi-squared test was applied to analyse the significance of the relationship between tsunami awareness and evacuation behaviour and the demographic characteristics of respondents. The analysis of the results demonstrates that although the respondents generally have a high level of tsunami awareness, younger people and Donggala Regency residents have an overall lower understanding of the phenomenon. It was also found that 82.5% of the population evacuated after witnessing others evacuating during the event. As there was no official warning to residents before the arrival of the tsunami, this social trigger played a significant role in prompting evacuation and decreasing the number of casualties. The present study also revealed that many people faced congestion while evacuating (especially in Palu City). This highlights the need to introduce additional tsunami disaster mitigation strategies to ensure that all residents can swiftly evacuate during such incidents.
View
... The initial wave arrived just 34 min after the earthquake ( Yamao et al. 2015), which explains the large numbers of casualties and the challenge that it represented from the long-term demographic sustainability of the town. Prior to the 2011 event, Otsuchi had a nominal population of around 16,000 people, and out of these 803 people died, 431 are still missing, and a further 140 50 lost their lives because of the indirect consequences of the tsunami (e.g. in the aftermath of the disaster some people died because they lost access to medicines needed to treat chronic illnesses ( Esteban et al. 2015). Regarding the damage, 3359 buildings were completely destroyed and another 713 suffered major or partial damage ( Esteban et al. 2015). ...
... Prior to the 2011 event, Otsuchi had a nominal population of around 16,000 people, and out of these 803 people died, 431 are still missing, and a further 140 50 lost their lives because of the indirect consequences of the tsunami (e.g. in the aftermath of the disaster some people died because they lost access to medicines needed to treat chronic illnesses ( Esteban et al. 2015). Regarding the damage, 3359 buildings were completely destroyed and another 713 suffered major or partial damage ( Esteban et al. 2015). ...
... It is worth noting that the town has a long history, and thus prior tsunamis have been well documented, as it served as a provincial capital during the Edo era. By 1948 the central downtown area was concentrated on the side of one of the hills, with the areas close to the sea left undeveloped, given that they were destroyed by previous tsunamis such as the 1896 Meiji-Sanriku and 1933 Showa-Sanriku events, and thus local inhabitants had a strong cultural memory of such types of disasters ( Esteban et al. 2015;Esteban et al. 2013). Nowadays, economic activities are based around the service sector, with a significant contribution of salmon fishing, aquaculture of scallops and seaweed, and the fish processing industry to the local economy. ...
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Disaster Risk Reduction is one of the most important topics in sustainability science, seeking to examine the vulnerability and resilience of human life and society to natural hazards through the reduction and management of risks. However, disasters are caused by many different types of natural hazard events that take place in exposed and vulnerable areas across time spans. The size of the area and times-scale of the impact can also differ greatly. Possible actions to improve preparedness, countermeasures, actors or stakeholders involved, and person(s) in charge of these measures vary depending on the type of disaster. This chapter describes two different types of coastal issues, namely tsunamis and sea level rise, and the types of countermeasures available to either Japanese coastal towns or small coral islands. How these issues are perceived and dealt with will then be discussed from the point of view of time-scales, which affect the human perception of the problem.
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... Considering that as part of the post-tsunami reconstruction process residential areas had been relocated to higher ground (see Refs. [56,57]); for a description of the philosophy followed regarding reconstruction) and many of the people visiting the beach were likely to be tourists, it would be unrealistic to assume that all evacuees would choose to go to the closest refuge are via the shortest route. Although the evacuation behaviors of evacuees during an emergency are not clear, the present study assumed that 50% of agents would proceed to the closest refuge area via the shortest route, whereas the other 50% would go to the second-closest one. ...
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View
... Countermeasures against coastal floods include building coastal protection structures such as seawalls, dikes and levees. Elevating the level of the ground can be costly, though it has been attempted along hundreds of kilometers of the Japanese coastline following the 2011 tsunami, in order to improve the resilience of coastal communities against such events (Esteban et al. 2015(Esteban et al. , 2018. At the bare minimum, crucial facilities such as the pump station and electricity control center should have anti-flooding systems to prevent the buildings from being flooded and be elevated to a higher level (such as the second floor of the same building) whenever possible. ...
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View
... This caused much of the coastline to be barely above sea level and large parts to be flooded at high tides. The Japanese government responded with a massive program of public works, raising some areas by up to 8 m and whole cities by 3 m, ensuring that no ground was lost to the sea (Esteban et al., 2015;Esteban et al., 2019). Of course, rich world wealth makes such an effort possible, but the fact that 200 km of coastline can be raised in a matter of years shows that it is possible and feasible to see adaptation to lower effective sea level rises happen over a century. ...
View
... For Fig. 8) example, the entire town of Minamisanriku is being raised by over 10 metres. This is not an exceptional case, but rather it is happening in all other towns and villages along the Rias coastline of the Tohoku region, which is hundreds of kilometres long (Kajima, 2017, Esteban et al., 2015c. However, raising the land in this way is complicated given the obvious resistance of people to be relocated during the construction period (which has lasted around 5 years for the case of Tohoku), and the financial cost involved. ...
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Full-text available
  • Sep 2013
Recent experience of large-scale water disasters such as Hurricane Katrina in 2005 and the Great Eastern Japan Earthquake and Tsunami in 2011 has reminded mankind that disasters cannot be ruledout. Unprecedented low-probability events can happen even in the most well monitored areas, causing major social-economic disruption. Failing to prepare for them may imply taking a risk that is not socially acceptable, but how much preparation for disasters can a modern society afford? Looking at flood risk management developments that have lately taken place in the Netherlands, the emergence of a virtual liking for disaster preparation measures is perceptible. Various technical studies have been made available presenting the effectiveness of such measures in the mitigation of expected fatalities and material damage. One of the most popular outlets of this trend is a suggestion in the National Water Plan of the Netherlands (2009) for the future to contemplate investments not only in flood-prevention measures, where the Dutch state has been investing heavily since 1960, but also in measures for the mitigation of losses. The existence of such a compound of measures signifies a socalled multi-layer safety system. Multi-layer safety has raised several discussions about its cost-efficiency. Previous studies have shown that combining flood-prevention with lossmitigating measures is generally speaking not costeffective. For a system that resembles the Netherlands, it has been shown that despite prevention, it is cost-effective to also invest a small amount in emergency management. This paper contributes in the above discussions by clarifying the economic implications of multi-layer safety from a rational perspective. In particular the objectives of the forthcoming analysis are 1) to clarify what is the most relevant information for decision makers regarding investments in multi-layer safety, and 2) to provide guidance on how to derive this information by means of cost-benefit analysis. The analysis is facilitated through a fictitious case study that refers to a coastal area, where the implementation of a multi-layer safety project is contemplated.
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A multi-layered safety perspective on the tsunami disaster in Tohoku, Japan
Conference Paper
Full-text available
  • Nov 2012
This paper presents an assessment of the multi-layered safety system in Tohoku, Japan based on the tsunami disaster of March 2011. The performed analysis has been based on data provided by local researchers and field observations. First an overview of the tsunami behaviour along the affected coastline of Tohoku is presented, which shows clearly that the disaster has site-specific features. The assessment that follows has a descriptive character and it is divided in two parts. First the performance of each safety layer in Tohoku is separately assessed, and conclusions are drawn for the efficiency of the system. The second part points out some implications of this disaster for the use of multi-layered safety in flood risk management.
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Evaluating Tsunami Risk and Vulnerability Along the Vietnamese Coast
Chapter
  • Dec 2014
The Vietnamese coast faces the East Sea, which has been recognized as having the potential to generate devastating tsunamis, thus requiring a careful consideration of tsunami risk. In this chapter, tsunami risk and vulnerability are analyzed based on the numerical simulation of tsunami propagation and the social and geographical background of Vietnam. The numerical simulation of a potentially hazardous earthquake scenario in the Manila Trench shows the distributions of the maximum tsunami amplitude and arrival time along the Vietnamese coast. When discussing the vulnerability of the coastline, particular attention is given to three main elements affecting this type of potential disaster in Vietnam: the extensive area of low-lying ground, namely large deltas; a lack of past experience regarding tsunami events; and underdeveloped tsunami mitigation measures. Tsunami mitigation measures implemented recently in coastal communities in Vietnam, such as tsunami warning stations and tsunami drills, are also mentioned.
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Evacuation Behaviors in the 2011 Great East Japan Earthquake
Article
  • Aug 2012
We studied relationships between evacuation place and time, predisaster preparedness, and evacuation behavior and survival rate for both the dead and missing and the survivors of the 2011 Great East Japan Earthquake. In order to elucidate the human impact, thousands of witnesses in areas from Tohoku to Kanto were analyzed. With a sample data number of 1,153, results show that behavior during the disaster differed for survivors and the dead and missing and that actual evacuation was associated positively with a higher survival rate. Based on these results, integrated strategies are proposed and discussed for the reduction of casualties in future large-scale natural disasters.
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Damage and reconstruction after the 2004 Indian Ocean tsunami and the 2011 Great East Japan tsunami, Journal of Natural Disaster Science
Article
  • Aug 2012
The 2004 Indian Ocean tsunami was one of the world’s worst tsunamis and caused devastating damage in many Asian countries. Then, in 2011, Japan was hit by a tsunami that was generated by the greatest earthquake in the country’s history. This paper discusses the damage caused by these tsunamis and subsequent reconstruction. Introduced first are the experience gained and lessons learned for future tsunami mitigation, such as tsunami awareness, proper evacuation building and the memorial parks created in the countries affected by the 2004 tsunami (Indonesia, Sri Lanka and Thailand). Second, the damage by the 2011 tsunami to structures designed to protect against tsunamis is summarized. Most of these structures could not withstand and protect from the tsunami because they were not designed for such a large tsunami. Human casualties and building damage are discussed using fatality ratios and fragility curves, respectively. These analyses show that experience and awareness help reduce human casualties in the Sanriku area, and wooden houses damaged by the 2011 tsunami fared better than in previous historical events. Finally, examples of ongoing reconstruction in Japan are introduced. Most reconstruction efforts were planned after considering the lessons learned from the tsunami’s impact, and the towns in question are now strengthening their disaster prevention-related plans to be better prepared for future tsunamis.
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