Fourteen years have passed since the Great East Japan Earthquake, and the importance of tsunami countermeasures has been reaffirmed. It has been revealed that over 100,000 residents in coastal areas of Miyagi Prefecture live in “evacuation-difficult areas.” This figure is based on evacuation plans set by municipalities according to new tsunami inundation projections.
Current State of Evacuation-Difficult Areas
Among the 15 coastal municipalities in Miyagi Prefecture, seven cities and towns have designated “evacuation-difficult areas.” These regions are concentrated in the flatlands of the central and southern parts of the prefecture. Specifically:
- Ishinomaki City: Approximately 79,400 residents
- Higashimatsushima City: Approximately 9,100 residents
- Tagajo City: Approximately 4,000 residents
An “evacuation-difficult area” refers to a region where it is challenging to evacuate to a safe location before a tsunami arrives. According to guidelines from the Fire and Disaster Management Agency, evacuation walking speed is estimated at 1 meter per second, with a maximum evacuation distance of about 500 meters.
Case Study: Watanoha District in Ishinomaki City
The Watanoha District in eastern Ishinomaki City was one of the areas most severely affected by the Great East Japan Earthquake. A tsunami as high as 5 meters inundated the area, destroying over 4,000 homes and claiming 519 lives.
Post-disaster reconstruction efforts included the construction of a 7.2-meter seawall, disaster prevention green spaces, and tsunami evacuation towers. However, new inundation projections predict that nearly the entire district could experience flooding of over 3 meters during a major tsunami event. The maximum wave height of 7.2 meters is expected to reach offshore approximately 56 minutes after an earthquake occurs.
Resident-Led Evacuation Measures
In Watanoha District, local leaders have spearheaded efforts to improve evacuation measures. A council was established to verify evacuation shelter capacity and create district-specific evacuation rules.
A survey revealed that half of households planning to evacuate prefer using vehicles. To address this, the council is exploring ways to designate evacuation routes for each area to alleviate congestion.
Efforts also include identifying households with elderly or vulnerable residents and securing new evacuation sites outside flood-prone areas. Eight potential locations have already been identified, with negotiations underway with landowners.
Challenges and Future Prospects
Addressing evacuation-difficult areas requires both infrastructure improvements and community-based measures. Associate Professor Shosuke Sato of Tohoku University’s International Research Institute of Disaster Science emphasizes that “current infrastructure cannot completely prevent tsunamis,” adding that sharing information between municipalities and residents is crucial for effective countermeasures.
Moreover, developing evacuation plans requires coordination between residents and authorities. Incorporating insights from third parties such as NPOs and experts has proven beneficial in some cases.
At our platform, “A World Without Tsunami Fatalities,” we advocate for leveraging LSA Code-certified products to further enhance survival rates during tsunami events. These products are designed based on cutting-edge scientific research and play a vital role in ensuring safety during evacuations.
While recovery efforts have progressed since the earthquake, protecting lives from future tsunami disasters remains an ongoing challenge. A combination of resident-led initiatives, administrative support, expert knowledge, and advanced disaster prevention technologies—such as LSA Code-certified products—will be essential for comprehensive solutions moving forward.
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