What is shindo, and how is it different from magnitude?
Shindo (seismic intensity) is JMA's 0 to 7 scale for how strongly the ground shook at a given place. Magnitude is the size of the earthquake at its source. The same earthquake has one magnitude and many intensities, one for each observation point. Travelers should read the intensity for where they are, not the magnitude.
JMA's description of each level
| Shindo | What people feel (JMA wording) |
|---|---|
| 0 | Imperceptible to people, but recorded by seismometers. |
| 1 | Felt slightly by some people keeping quiet in buildings. |
| 2 | Felt by many people keeping quiet in buildings. Some people may be awoken. |
| 3 | Felt by most people in buildings. Felt by some people walking. Many people are awoken. |
| 4 | Most people are startled. Felt by most people walking. |
| 5 Lower | Many people are frightened and feel the need to hold onto something stable. |
| 5 Upper | Walking is difficult without holding onto something stable. |
| 6 Lower | It is difficult to remain standing. |
| 6 Upper | It is impossible to remain standing or move without crawling. |
| 7 | People may be thrown through the air. |
Why it varies
Intensities are measured by instruments at fixed points and vary with underground conditions and topography
. A report of shindo 5 Lower for a prefecture does not mean your street shook that hard, or that it did not shake harder.
The one rule
While it shakes: drop, get under a sturdy table, cover your head, and do not run outside. Falling glass, tiles and signboards injure people who run.
In the app
Japan Disaster Guide lets you choose the intensity at which you are notified (3, 4 or 5 Lower). During an aftershock sequence, raising it cuts the noise while the important alerts still get through.
The live warnings, in your language
Japan Disaster Guide is a free iPhone app that delivers JMA warnings for the places you save, after JMA confirms them, in 7 languages, with 115,000+ evacuation sites on a map.
Free on the App Store See the Japan Travel Safety KitThe full procedures, the 119 script, shelter life, the 171 steps, 21 pointing cards and the worksheets are in the Japan Travel Safety Manual, a 66-page PDF made to read on a phone.
Get the manual ($9.99 PDF)- Japan Meteorological Agency, Seismic Intensity Scale (English). https://www.jma.go.jp/jma/en/Activities/inttable.html
- Tokyo Metropolitan Government, Disaster Preparedness Tokyo (2023, English). https://www.bousai.metro.tokyo.lg.jp/_res/projects/default_project/_page_/001/029/136/tb2023_e_00.pdf
Japan Disaster Guide is an independent app. It is not affiliated with the Japan Meteorological Agency or any government body. In an emergency, follow the instructions of local officials.
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