東日本大震災以降、私は保育施設の津波避難安全について研究に取り組んでいます。保育施設では、保育士等職員のみの裁量では対応が困難であり、沿岸部に位置する施設は、高台など津波から安全な場所に予め移転させる必要があると考えています。
東日本大震災では、岩手県・宮城県・福島県において被災した722の保育施設の内、78の施設が津波で全壊・半壊しました。数多くの施設が被災した一方、保育中に死亡した園児は1施設の3名のみであり、事前の備えが人的被害の抑制につながったという印象が世論に広まっているかもしれません。毎月実施される避難訓練が活かされたことや保育施設職員による懸命な対応が被害を最小限に抑えたことは確かであると思います（資料1，2）。しかし、震災時に園児の避難誘導を行った保育士へ調査を実施した結果、現場では想定を超える高さの津波襲来や津波火災による延焼等の二次災害の危険性が甚大になるにつれて、避難場所を何度も変更するなど、多くの保育施設で事前の避難計画と異なる行動や危険がつきまとう対応をせざるを得ない傾向が確認されました。特に傾斜地では、歩行が困難な乳幼児の搬送を行う保育士の身体的負担に伴い、避難先の選択が課題となりました。津波到達直前に合流した地域住民等の支援のおかげで助かったという事例は少なくはありません（資料1，2）。
今後、関東から九州の広い範囲で強い揺れと高い津波をもたらすとされる南海トラフ地震が発生した場合には、どれくらいの保育施設が津波で被災する可能性があるのか。その答えを求めるために、南海トラフ地震津波避難対策特別強化地域指定市町村における保育施設所在地の標高（2017年7月時点）と最大津波高（資料3，市町村別・11ケース別最大値）を地理情報システムで解析しました。暫定的な推計結果として、該当市町村では2,493の保育施設の内、最大1,265の施設が津波で浸水する可能性のある場所に位置していることが分かりました。当然ながら、該当施設では津波が到達する前に園児の避難対応を完了させる必要があります。果たして、対応が間に合わず、園児が津波に巻き込まれてしまうリスクはどの程度あるのか。避難安全検証にあたって、避難所要時間推計モデルや避難シミュレーションモデルの開発に取り組んでいます。開発途中ですが、保育士の身体的負担等を考慮したモデル改良が進むほど、保育園児・職員の甚大な人的被害を避けることはほぼ不可能であるという危機的な状況が示される傾向にあります。
実際に、東日本大震災では、津波到達時間が最短で25分でしたが、南海トラフ地震では津波到達時間が最短で3分、平均で22分と想定されています（資料3，都道府県別・11ケース別・津波高5メートル最短値）。南海トラフ地震では、東日本大震災より津波到達時間が短く、破壊的な激震の継続時間も長いと予想されていることから、避難行動が遅くなってしまい、沿岸部に位置する保育施設において史上最悪の被害が発生する可能性が懸念されます。保育施設では、避難行動に困難を伴うことは明らかで、避難しなくてもよい安全な立地や施設づくりを最優先で取り組むべきです。東日本大震災以降、国内各地で保育施設を含む要配慮者利用施設の高台移転が進んでいますが、具体的な実態は把握できていない状況です。皆様のご意見や自治体で進められている取り組みについて、教えていただけますと幸いです。また、多種多様なシナリオに対応する避難シミュレーションモデルの改良にあたって、保育施設の津波避難訓練の様子をご見学いたしたく存じます。そして、保育施設の高台移転の必要性について、周知啓発にご協力をお願い申し上げます。
連絡フォーム：http://contact.abel.pw
参考資料
- 論文: 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.
URL: http://www.lib.kobe-u.ac.jp/infolib/meta_pub/G0000003kernel_90008126 - 発表動画・スライド冊子:ピニェイロ アベウ タイチ コンノ，津波襲来時における保育施設の避難対応と課題～東日本大震災での経験から考える，第257回神戸大学都市安全研究センターRCUSSオープンゼミナール, 2020/6.
URL: https://open.kobe-u.rcuss-usm.jp/archive/257 - 内閣府防災公開資料：南海トラフ巨大地震対策検討WG市町村別最大津波高一覧表＜満潮位＞，都府県別津波到達時間一覧表（平成24年8月29日）.
URL: http://www.bousai.go.jp/jishin/nankai/nankaitrough_info.html
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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.
Contact form: http://contact.abel.pw
Reference materials
- 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 - 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 - 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
