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Educational guide, not an alert service: no live data. Always follow official instructions from JMA, your municipality, police, fire and staff. In an emergency, protect yourself first. Full disclaimer

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Japan alert decoder · 南海トラフ地震臨時情報（巨大地震警戒）

Nankai Trough Earthquake Extra Information (Megathrust Earthquake Alert)

Elderly / slow evacuees go now; others get ready · official rules as of 2026-10-17

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Elderly / slow evacuees go now; others get ready

南海トラフ地震臨時情報（巨大地震警戒）

Nankai Trough Earthquake Extra Information (Megathrust Earthquake Alert)

A large quake (about Mw8+) has hit part of the Nankai Trough, so a second megaquake is relatively more likely. It is not a prediction that one will happen.

What to do now

  1. If your municipality says so (areas a tsunami could reach before you can escape), pre-evacuate for one week.
  2. Everyone else: re-check your emergency kit, furniture fixing and evacuation route, and be ready to evacuate at once if a quake hits.

How long: About one week of pre-evacuation, then another week of heightened caution.

Issued by: JMA, with government and municipal calls for action. Live status: JMA warnings map (English)JMA earthquake information (English)JMA tsunami information (English)

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Educational guide, not an alert service: no live data. Always follow official instructions from JMA, your municipality, police, fire and staff. In an emergency, protect yourself first.

Data as of 2026-10-17 from official JMA, Cabinet Office, Cabinet Secretariat (J-ALERT) and Ministry of the Environment pages, with official names from the JMA multilingual dictionary (2026-03-26). Not affiliated with JMA or any government agency.

Educational guide, not an alert service: no live data. Always follow official instructions from JMA, your municipality, police, fire and staff. In an emergency, protect yourself first. Data as of 2026-10-17 from official JMA, Cabinet Office, Cabinet Secretariat (J-ALERT) and Ministry of the Environment pages, with official names from the JMA multilingual dictionary (2026-03-26). Not affiliated with JMA or any government agency.