Japan's Earthquake Early Warning: Understanding the Alert on Your Phone
Quick answer
It is Japan's Earthquake Early Warning, sent by the Japan Meteorological Agency when strong shaking is expected. It gives you a few seconds, sometimes none, before the ground moves. Do not investigate the sound. Protect your head, drop, and take cover until the shaking stops.
What is that loud alarm my phone just made?
If your phone suddenly blared a harsh two-tone chime and showed a red or Japanese-language message, you almost certainly received an Earthquake Early Warning (緊急地震速報). It is issued by the Japan Meteorological Agency (JMA), Japan’s official weather and earthquake authority, and it means the same thing every time: strong shaking may be about to arrive.
The most important thing to understand is that this is not a message to read. By the time you unlock your phone to translate the text, the useful seconds may already be gone. The sound is the instruction. When you hear it, stop what you are doing and protect yourself first.
Use this table to tell the alert apart from ordinary notifications:
| What you notice | What it means |
|---|---|
| Harsh two-tone chime that overrides silent mode | Earthquake Early Warning or another emergency alert |
| Message titled 緊急地震速報 | Earthquake Early Warning (shaking expected) |
| The alarm repeats or several phones nearby sound at once | A real broadcast, not your phone alone |
| A calmer news or app notification | General information, not an immediate warning |
How does the warning reach my phone at all?
You did not need to install anything. The warning is sent by cell broadcast, a one-to-many system that pushes the same message to every compatible phone connected to a Japanese mobile network in the target area. Because it is built into the phone and the network, it works on many foreign handsets and roaming SIMs too, as long as the phone supports the standard.
Behind the scenes, JMA runs a dense nationwide network of seismometers. When an earthquake begins, sensors near the source detect the first, faster, weaker waves (P-waves) and the system estimates the location and size within seconds, then predicts where stronger, slower shaking (S-waves) will be felt. That race between the warning and the damaging waves is what buys you time.
As of July 2026, JMA issues an Earthquake Early Warning to the general public when the estimated maximum seismic intensity reaches 5-lower (5弱) or above on Japan’s shindo scale, targeting areas where an intensity of 4 or higher is expected. In plain terms: the alert fires when meaningfully strong shaking is likely, not for every small tremor.
How much warning time will I really get?
Honestly, not much, and sometimes none. The warning can only outrun the shaking by the difference in wave speeds, so the closer you are to the epicenter, the less lead time you have.
| Your distance from the source | Typical warning time | What this means for you |
|---|---|---|
| Directly above or very close | 0 seconds, or shaking first | You may feel it before the alert; react to the ground, not the phone |
| Nearby (tens of km) | A few seconds | Enough to drop and cover if you move at once |
| Farther away | Up to tens of seconds | Time to move away from glass and take cover calmly |
Because the time is so short, the rule is simple: do not investigate the alarm, act on it. Even a two-second head start is enough to get under a table or away from a window.
What should I do the moment I hear it?
The internationally recognised response, used across Japan, is Drop, Cover, Hold On. Do it the instant the alarm sounds, before you feel anything.
| When | What to do |
|---|---|
| The alarm sounds | Stop moving; do not run for an exit |
| Immediately | Drop low, get under a sturdy table or desk |
| While shaking | Cover your head and neck; hold on to the table leg |
| Near windows or shelves | Move away first; falling glass causes many injuries |
| If outdoors | Move to open space away from walls, signs, and vending machines |
| If driving | Slow down gently, pull over, stop, stay inside |
| In an elevator | Press every floor button and get out at the first that opens |
Stay in your covered position until the shaking fully stops. Aftershocks can follow, so do not rush. Once it is safe, follow instructions from hotel, station, or shop staff, keep your shoes on for broken glass, and use stairs rather than elevators.
If you are near the coast and receive a separate tsunami warning, move to high ground or a tall, sturdy building at once and stay there until officials confirm it is safe. Do not return to the shore.
Quick reference: reading the alert
| Topic | Detail (as of July 2026) |
|---|---|
| Who sends it | Japan Meteorological Agency (JMA) |
| Message name | 緊急地震速報 (Earthquake Early Warning) |
| How it reaches you | Cell broadcast to compatible phones on Japanese networks; no app needed |
| When it fires | Estimated max intensity 5-lower or above; alerts areas expecting intensity 4+ |
| Warning time | A few seconds to none, depending on distance |
| Language | Japanese by default; use the Safety Tips app for English alerts |
| First action | Drop, Cover, Hold On — do not read the phone first |
| Different warning | Tsunami warnings are separate and come later near the coast |
This is general safety information, not a substitute for official instructions. If you are unsure what to do, follow the guidance of local staff and authorities, and check the official JMA and Japanese government sources for current details.
FAQ
Why did my phone make a loud alarm even though I did not download anything?
Japan's Earthquake Early Warning is broadcast to every compatible phone on a Japanese network through a cell-broadcast system. You do not need an app or a subscription, and it works even on a foreign SIM or roaming phone if the handset supports the standard. The alarm is meant to be jarring so it wakes you and interrupts whatever you are doing.
The alert was in Japanese and I could not read it. What was it telling me?
The default alert appears in Japanese with a distinctive two-tone chime. The message name is 緊急地震速報 (Earthquake Early Warning). The exact words matter less than the meaning: strong shaking may arrive in seconds. Treat the sound itself as the instruction to take cover. For alerts in English, install the official Safety Tips disaster app before you travel.
How many seconds of warning will I actually get?
It varies from a few seconds to none. The warning travels faster than the damaging shaking, so people far from the source get more time and people directly above it may feel the quake before or as the alert arrives. As of July 2026, treat any warning time as very short and act immediately rather than checking your phone.
My phone alarmed but I felt nothing. Was it a false alarm?
Not necessarily. The system estimates the size and location from the first seismic waves within seconds, so the shaking may be weaker where you are than predicted, or you may be far enough away to barely feel it. Occasional over-warnings are the trade-off for speed. Always react as if shaking is coming, and be glad when it turns out mild.
Is the earthquake alert the same as a tsunami warning?
No. The Earthquake Early Warning is about ground shaking and comes first. A tsunami warning is separate and follows later, issued by the Japan Meteorological Agency within a few minutes if a quake could raise the sea. If you are near the coast and hear or see a tsunami warning, move to high ground immediately and stay there until officials say it is safe.