Tsunami warning in Japan: when to move, and when you can go back
Six real situations from the app's deck — long shaking on the coast, a warning without any shaking, two hours on the hill — with the official answer and its source.
🏖️ You're walking near the seafront in a coastal town. A strong earthquake shakes the ground for a long time.
What should you do as soon as the shaking stops?
✅ The right move: Move immediately to higher ground, away from the coast
Why: A strong or long earthquake near the coast is itself a tsunami warning. Move to higher ground immediately — don't wait to see the sea change. The Japan Meteorological Agency issues tsunami warnings within minutes, but the first wave can arrive even faster, and it is not always the largest.
Source (summarized): Japan Meteorological Agency — Tsunami Warning/Advisory and Tsunami Information
🌅 You're strolling along a seaside promenade. The ground begins to sway — gently, but it goes on for a strangely long time.
The shaking was weak. What should you do?
✅ The right move: Start evacuating to higher ground immediately — long shaking near the coast is a sign of a tsunami
Why: Official guidance is explicit: when there is a strong — or weak but long-lasting — earthquake near the coast, start evacuating. A slow, long swaying can mean a large, distant earthquake capable of generating a tsunami. Don't wait for the official warning to begin moving.
Source (summarized): Safety tips for travelers (Japan Tourism Agency / JNTO)
📲 You're in a coastal town. A tsunami warning appears on your phone — but you never felt any shaking at all.
What should you make of it?
✅ The right move: Take it seriously and evacuate — a tsunami can come even when you felt no shaking
Why: A tsunami can arrive even when you felt no shaking at all. Official guidance: when a warning is issued, ensure your safety — don't judge the danger yourself; evacuate to elevated ground and stay until warnings are lifted.
🗺️ After an offshore earthquake, the TV shows a map of Japan's coastline with some segments colored and others not.
How does JMA issue tsunami warnings?
✅ The right move: Per coastal region, based on estimated tsunami heights for each
Why: When disastrous waves are expected, JMA issues a Tsunami Warning or Advisory for each coastal region expected to be affected, based on estimated tsunami heights. The colored map shows which stretches of coast must evacuate — check whether yours is one of them.
⛰️ You evacuated uphill from a tsunami warning two hours ago. Nothing dramatic seems to have happened, and your hotel is by the shore.
When can you go back down?
✅ The right move: Only after the warning is officially canceled
Why: Stay on high ground until warnings are officially canceled. Tsunami strike repeatedly over long periods, and a quiet interval does not mean it is over. Follow official information — not the crowd, and not how things look. If the warning is downgraded to an advisory, stay out of the water and away from the shore until the advisory is cleared too.
Source (summarized): Safety tips for travelers (Japan Tourism Agency / JNTO)
🎒 A tsunami warning sounds. Your passport, laptop, and luggage are in your beachfront hotel room on the 2nd floor.
What do you do?
✅ The right move: Leave your belongings and evacuate to high ground immediately
Why: Evacuate immediately — belongings can be replaced, and passports can be reissued through your embassy. Guidance is clear: don't stop to evaluate or collect things; move to elevated ground at once. Minutes matter with a tsunami.
Source (summarized): Safety tips for travelers (Japan Tourism Agency / JNTO)
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One question a day on earthquake safety in Japan, with show-and-point emergency cards and an offline guide. Five languages, all free.
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