Earthquake alerts in Japan: what reaches a visitor's phone

When the Japan Meteorological Agency expects strong shaking immediately after an earthquake, it issues an Earthquake Early Warning as quickly as it can, with estimated arrival times and seismic intensities. The Japan Tourism Agency's Safety tips site for international visitors explains that the warning is broadcast with a special alarm sound on television, radio, mobile phones and smartphones. The Meteorological Agency also issues tsunami warnings, weather warnings and, when there is a strong possibility of a devastating disaster of the kind that occurs once every several decades, Emergency Warnings.

What matters for a visitor is the line as much as the handset. Apple's guidance for iPhone users in Japan says the alerts come from the Japan Meteorological Agency and the Japanese government, and that they are supported when you use a SIM card or eSIM from a supported network provider; it points to the emergency notification services of SoftBank, KDDI and NTT DOCOMO for the detail. An iPhone that qualifies can show earthquake alerts, tsunami alerts and other disaster information, translated into the language set on the phone.

If you are using a travel eSIM, that makes one question worth asking before you buy: whether the Japanese network the plan uses delivers these alerts to its customers. Android phones manage broadcast warnings in their own settings, and Google describes Wireless emergency alerts as the place to turn alert types on or off, look back at past alerts and control sound and vibration. Neither setting helps if it has been switched off, so check every phone in your group, whatever it runs.

Because a phone's built-in alerts depend on details that are hard to confirm from home, it is sensible to add a route that does not. The Japan Tourism Agency's Safety tips app was made for foreign tourists: it pushes Earthquake Early Warnings, tsunami warnings and other weather warnings within Japan in 15 languages, among them English, Korean, Simplified and Traditional Chinese, Vietnamese, Spanish, Portuguese and Thai.

The app is more than an alarm. It includes an evacuation flowchart that suggests what to do depending on your surroundings, phrases for getting information from the people around you, and links to websites that are useful in a disaster. It is available for both iPhone and Android, so a whole family or group can use the same tool, and because its warnings arrive as push notifications, allow them when you install it and keep the phone connected while you travel.

Most of the preparation takes a few minutes on Wi-Fi at home. The aim is two independent channels, the phone's own alerts and the app, and enough familiarity with both that an alarm is recognisable rather than baffling when it arrives.

Ask one more question when you check in. Local governments designate public facilities such as schools and community centres as evacuation shelters, and some hotels and Japanese inns are designated to accept evacuated residents during a disaster, so the Safety tips site suggests confirming the arrangements with your accommodation.

An Earthquake Early Warning is a prompt to protect yourself, not to reach for the news. The Safety tips guidance is to stay calm and make yourself safe first, depending on where you are, even if you have not felt any shaking yet. Earthquake-resistant construction is widespread in Japan and most buildings are fairly resistant to earthquakes, so if you are inside one when the shaking starts, the advice is not to go outside until it is safe.

Near the coast, the advice changes. The Japan Meteorological Agency issues a tsunami warning roughly three minutes after an earthquake when it expects damage, but visitors are told not to wait for it: after strong shaking, or weaker shaking that goes on for a long time, start moving to higher ground without trying to judge the risk yourself. Stay there until the warning has been cancelled, because tsunamis strike repeatedly over a long period.

Once you are safe, use the phone to follow what has actually been issued. The Safety tips website brings the Meteorological Agency's current warnings, advisories and earthquake information together in one place, alongside transport information, and it links to NHK WORLD, Japan's public broadcaster, for news.