Free · Japan · 緊急速報 · data 2026-10-17
What does this Japanese alert mean?
Japan emergency alert decoder: earthquake, tsunami, Level 1-5 warnings, evacuation, J-ALERT
Paste the alert your phone, TV or app showed (Japanese or English). Get what it is, the alert level, what to do right now where you are, and its official name in 14 languages. Includes the new level-named warnings that started on May 29, 2026.
Or tap one
緊急地震速報（警報）
Earthquake Early Warning (EEW)
An earthquake has just started and strong shaking (seismic intensity 5-lower or more, or long-period ground motion class 3+) is predicted. JMA sends it when two or more seismometers detect the quake; the areas named expect intensity 4 or more. You have seconds to tens of seconds, or none if you are near the epicentre. It is a prediction: real shaking can be stronger or weaker, and it does not say exactly when shaking arrives.
What to do now
- Protect yourself first: take cover under a sturdy table or desk and protect your head.
- Stay away from windows, shelves, TVs and anything that can fall.
- Do not rush outside and do not try to put out fires until the shaking stops.
- Tell people around you.
- When the shaking stops: if you are near the coast, check for a tsunami warning; then check for fire and gas.
Don't
- Don't run outside during shaking (falling glass, signs, tiles).
- Don't use elevators.
- Don't brake suddenly while driving.
How long: Shaking lasts seconds to minutes. Aftershocks are common for days, and strong ones can follow.
On 2026-10-16 at 12:40 JST JMA issued an EEW (warning) from Hokkaido to Chubu after over-estimating a distant quake as M9.9 near the Kuril Islands; it was later cancelled. JMA says a filter that ignores stations more than 700 km away had not worked; it fixed it at about 21:30 that day and apologised. False alarms are rare, so act on every EEW.
Issued by: Japan Meteorological Agency (JMA); pushed to every phone in the area by the carriers (loud buzzer), plus TV and radio. Live status: JMA warnings map (English)JMA earthquake information (English)JMA tsunami information (English)
Japan's 5 alert levels (since 2026-05-29)
| Level | Weather warning (JMA) | Evacuation info (your city) | What to do |
|---|---|---|---|
| 5 · black | 特別警報 Emergency Warning | 緊急安全確保 Emergency Safety Measures | Take the safest action immediately; a disaster is happening or imminent. |
| 4 · purple | 危険警報 Urgent Warning | 避難指示 Evacuation Instruction | Everyone in danger areas evacuates now. |
| 3 · red | 警報 Warning | 高齢者等避難 Evacuation of the Elderly, etc. | Elderly and slow evacuees go now; others prepare. |
| 2 · yellow | 注意報 Advisory | — | Check the hazard map and your route. |
| 1 · white | 早期注意情報 Early Advisory | — | Stay alert. |
Old name → new name
Main sources: JMA new disaster weather information (2026), JMA Earthquake Early Warning, JMA multilingual dictionary, Cabinet Office and J-ALERT pages; every source in /api/rules.
For AI agents and developers
Keyless JSON, CORS open, GET or POST: /api/decode?text=レベル4土砂災害危険警報&lang=vi. All alert types: /api/rules. Docs: OpenAPI, llms.txt, MCP tool japan_emergency_alert_decode on free-agent-tools.
Japan alert questions
My phone in Japan made a loud alarm and said 緊急地震速報. What do I do?
That is the Earthquake Early Warning (EEW): strong shaking is expected within seconds. Protect your head and get under a sturdy table, stay away from windows and things that can fall, and don't run outside. On a train hold the strap; driving, turn on hazard lights and slow down gradually; in an elevator stop at the nearest floor and get out. After the shaking, if you are near the coast, check for a tsunami warning.
Why was the October 16, 2026 earthquake early warning cancelled?
At 12:40 JST on October 16, 2026 JMA issued an EEW (warning) from Hokkaido to Chubu after its system over-estimated a distant quake near the Kuril Islands as M9.9. It was later cancelled (先ほど発表した緊急地震速報を取り消します = 'JMA has cancelled the EEW'). JMA said a filter that ignores stations more than 700 km away had not worked, fixed it at about 21:30 that day and apologised. False alarms are rare; keep acting on every EEW.
What are Japan's new Level 4 'Urgent Warnings' (危険警報)?
Since May 29, 2026 Japan's heavy-rain, flood, landslide and storm-surge warnings carry the alert level in their name. Level 5 特別警報 Emergency Warning (black), Level 4 危険警報 Urgent Warning (purple, new), Level 3 警報 Warning (red), Level 2 注意報 Advisory (yellow) and Level 1 早期注意情報 Early Advisory (white). For example 土砂災害警戒情報 became レベル4土砂災害危険警報 (Level 4 Urgent Warning (Landslide)). Evacuate from dangerous areas by Level 4.
What is the difference between 避難指示 and 高齢者等避難?
They come from your city or town. 【警戒レベル4】避難指示 (Evacuation Instruction): everyone in the named danger area evacuates now. 【警戒レベル3】高齢者等避難 (Evacuation of the Elderly, etc.): elderly people and anyone who needs time go now; others prepare. 【警戒レベル5】緊急安全確保: a disaster is happening; take the safest action immediately. 避難勧告 was abolished in 2021.
What do 大津波警報, 津波警報 and 津波注意報 mean?
大津波警報 Major Tsunami Warning: over 3 m expected (announced as 5 m, 10 m, over 10 m or 'huge'). 津波警報 Tsunami Warning: 1-3 m. Evacuate immediately to high ground or an evacuation building for both. 津波注意報 Tsunami Advisory: 0.2-1 m; get out of the water and leave the coast. Waves repeat for hours; stay away until the warning is lifted (解除).
What is the 線状降水帯 (linear rainband) alert?
Since May 29, 2026 it is sent as 気象防災速報（線状降水帯発生）, a weather disaster bulletin: a line of thunderstorms is dropping very heavy rain on the same place for hours, so floods and landslides can come fast. Check your area on JMA's KIKIKURU map and evacuate early from slopes and low ground. A new 線状降水帯直前予測 gives about 2-3 hours' notice.
What does 南海トラフ地震臨時情報（巨大地震注意） mean?
Nankai Trough Earthquake Extra Information (Megathrust Earthquake Attention): a quake of about M7+ in the Nankai Trough area means a megaquake is relatively more likely than usual for about a week. It is not a prediction. Live normally, re-check water, food and your evacuation route, and be ready to evacuate at once if you feel a quake near the coast. 巨大地震警戒 (Alert) is stronger: some coastal residents pre-evacuate for a week.
What do I do if I get a J-ALERT missile alert?
Outdoors, go into a sturdy building or underground (a subway station) right away; with no building nearby, take cover or lie flat and protect your head. Indoors, move away from windows. A missile can arrive in under 10 minutes. Follow-up messages say whether it passed over or landed.
Is this an alert app? Does it show live alerts?
No. It has no live data and sends no alerts. It explains an alert you already received, using dated official rules. For current alerts use JMA's warnings and earthquake maps (linked in every result), your phone's emergency alerts and the Japan Tourism Agency's Safety tips app. Always follow official instructions.
Is there a free API for AI agents to decode Japanese alerts?
Yes. Free, no key, CORS open: GET https://japan-alert-decoder.vercel.app/api/decode?text=レベル4土砂災害危険警報 returns the alert, level, colour, urgency, meaning, what to do, official names in 14 languages and sources. All alert types at https://japan-alert-decoder.vercel.app/api/rules, OpenAPI at https://japan-alert-decoder.vercel.app/openapi.json, and the japan_emergency_alert_decode tool on https://free-agent-tools.vercel.app/mcp.
スマホに届いた緊急速報の意味を英語で知るには？
警報の文面をそのまま貼り付けると、何の情報か、警戒レベル、今すぐ取るべき行動、気象庁の多言語辞書による公式名称（英語・中国語・韓国語・ベトナム語など14言語）を表示します。2026年5月29日からの新しい防災気象情報（レベル4土砂災害危険警報など）と旧名称（土砂災害警戒情報、洪水警報など）の対応にも対応しています。
「危険警報」とは何ですか？
2026年5月29日から始まった新しい防災気象情報で、警戒レベル4相当の情報です（紫）。大雨・土砂災害・氾濫・高潮の4つがあり、例えば土砂災害警戒情報はレベル4土砂災害危険警報になりました。危険な場所にいる人は全員避難します（レベル4までに必ず避難）。