SHINDO's server in Tokyo receives every 緊急地震速報 the moment JMA releases it and pushes it as a critical alert that sounds through Silent and Focus modes.
A nationwide siren teaches people to ignore it. SHINDO applies JMA's forecast intensity for your prefecture — and, where JMA splits them, your Hokkaido region or island group — so the alarm you get is the one you need: full siren for a strong forecast, a banner for a weak one, silence for an earthquake that will not reach you.
JMA revises a warning several times as more sensors report. SHINDO sounds the alarm once on the first message, updates the intensity quietly, and only sounds again if the forecast for your area jumps to a higher tier.
When JMA cancels — as it did on 16 October 2026 for a phantom magnitude 9.9 — SHINDO replaces the alert on every device that was warned, ends the Lock Screen countdown, and tells you it was withdrawn.
The Japan Meteorological Agency publishes the early warning with a forecast intensity per area and an estimated arrival time.
Our server receives it through the P2P地震情報 network within about three seconds and looks up every device's area.
Each phone gets the alert tier for its own area. Devices abroad get a quiet banner in Watch mode.
Apple's push service carries it as a Critical Alert, so it sounds even on Silent — once you allow it.
Without it, iOS treats an early warning like any notification and keeps it silent in Focus or Silent mode. Critical Alerts are Apple's category for exactly this; you grant it once and can revoke it in Settings.
Push alerts need a network. Your carrier's own emergency broadcast (緊急速報) does not, which is why we ask you to keep it on. SHINDO Node adds a radio path for messaging when networks are down.
No. SHINDO relays and explains JMA's warnings and reports. It does not detect or forecast earthquakes.