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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（巨大地震注意）

Nankai Trough Earthquake Extra Information (Megathrust Earthquake Attention)

Prepare and check your route · official rules as of 2026-10-17

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Prepare and check your route

南海トラフ地震臨時情報（巨大地震注意）

Nankai Trough Earthquake Extra Information (Megathrust Earthquake Attention)

A quake of about M7+ (or unusual slow slip) occurred in the Nankai Trough area, so a megaquake is relatively more likely than usual. No pre-evacuation. It was first issued in August 2024.

What to do now

  1. Live normally but re-check your preparations (water, food, furniture, evacuation route).
  2. Be ready to evacuate immediately if you feel a quake, especially near the coast.

How long: About one week of heightened caution.

Issued by: JMA, with government 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.