Monday, January 10, 2022


Activity report: Tsunami damages expected in childcare centers in the event of Nankai Trough Earthquake in Japan and the need for relocation to higher ground


Since the 2011 Great East Japan Earthquake and Tsunami, I have been conducting research on tsunami evacuation safety in childcare facilities. Considering the cope capacity of the childcare staff, the difficulty of facilities to respond to tsunami evacuation is evident. I believe that facilities located in coastal areas need to be relocated in advance to higher grounds that are safe from the tsunami.


In the 2011 Earthquake, 722 childcare facilities in Iwate, Miyagi, and Fukushima prefectures were affected by catastrophe; of these 722 facilities, 78 were totally or partially damaged by tsunami. While many facilities were affected, only three children from one facility were fatal victims while in the facility's care. Indeed, the monthly evacuation drills and the hard response of the facility staff contributed to minimizing the damage (Refs. 1 and 2). However, as a result of research conducted after the disaster, it was observed that many facilities were forced to take actions that differed from their pre-existent evacuation plans under dangerous conditions. For example,  the evacuation destination needed to be changed multiple times (in the face of increased secondary disasters, such as a tsunami that was higher than expected or the spread of fire due to a tsunami). In particular, the choice of evacuation sites on sloping terrain became an issue, due to the physical burden on childcare staff who had to transport infants who had limited walking capability. There were many cases where children were saved thanks to the support of local residents etc., who gathered along the escape route just before the arrival of the tsunami (Ref.1, 2).

In the event of a future Nankai Trough Earthquake, it is estimated that strong tremors and high tsunamis will reach large areas in the west of Japan. How many childcare facilities are likely to be damaged by the tsunami? To find the answer to this question, I used GIS to analyze the altitude of the childcare facilities (as of July 2017) and the maximum estimated tsunami heights (Ref. 3, maximum values by municipality, by 11 cases). This analysis considered facilities located in cities designated as "Specially Enhanced Tsunami Evacuation Countermeasures Areas for Nankai Trough Earthquakes". As a tentative estimation result, I found that a tsunami could inundate up to 1,265 of the 2,493 childcare facilities located in those areas. Obviously, these facilities need to evacuate their children before the tsunami arrives. What is the risk of children being stricken by tsunami if the evacuation is not completed in time? To evaluate the evacuation safety, I am developing an evacuation simulation model that calculates the time required for evacuation for each facility. The more the calculation models are improved, taking into account the physical burden on childcare staff, the more they tend to show the critical situation. The preliminary simulation result shows that it is almost impossible to avoid severe casualties among children and staff.

In fact, in the 2011 Earthquake in Japan East Coast, the shortest tsunami arrival time was 25 minutes. Despite in the future Nankai Trough Earthquake in Japan West Coast, the shortest tsunami arrival time is assumed to be 3 minutes, and the average is 22 minutes (Ref. 3, minimum values by prefecture, by 11 cases, by 5-meters tsunami height cases). In the case of the Nankai Trough Earthquake, the tsunami arrival time is expected to be shorter, and the duration of destructive quakes to be longer than those of the 2011 Earthquake. The evacuation response will probably be delayed, and the concern that daycare centers will suffer the worst damage in history is unavoidable. Therefore, the highest priority must be relocating those facilities to higher places that do not require evacuation. Since the 2011 Earthquake, the relocation of facilities for people in need of care to higher ground (including childcare facilities) has progressed in various parts of Japan. However, we have not been able to ascertain the actual situation. I would be grateful if you could share your opinions and the efforts being made by local governments. I would also like to request cooperation from the daycare centers to observe how the evacuation drills are being carried out. This cooperation would be crucial to constructing simulation models that are compatible with various scenarios. And I definitely ask for your collaboration in raising awareness regarding the necessity of relocating childcare facilities to higher and safer places.

Reference materials

  1. Refereed publication (in English): Abel Táiti Konno Pinheiro and Akihiko Hokugo, Effectiveness of early warning and community cooperation for evacuation preparedness from mega-risk type coastal hazard in childcare centers, International Journal of Disaster Resilience in the Built Environment, 10(4), 260-275, 2019/8.
    URL1: https://doi.org/10.1108/IJDRBE-05-2019-0023
    URL2: http://www.lib.kobe-u.ac.jp/repository/90008126.pdf
  2. Presentation video / slide handout (in Japanese): Abel Táiti Konno Pinheiro, Evacuation Response and Issues regarding Childcare Facilities in the Event of a Tsunami Strike: Considerations from the Experience of the Great East Japan Earthquake, The 257 Kobe University Research Center for Urban Safety and Security Open Seminar, June 2020.
    URL: https://open.kobe-u.rcuss-usm.jp/archive/257
  3. Documents released by Japan Government Cabinet Office Disaster Prevention (in Japanese): Nankai Trough Mega Earthquake Countermeasures Study Working Group, List of Maximum Tsunami Heights by Municipality <High Tide Level>, List of Arrival Time of Tsunami by Prefecture (August 29, 2012).
    URL: http://www.bousai.go.jp/jishin/nankai/nankaitrough_info.html