The JMA Seismic Intensity Scale (Shindo)
Japan reports earthquakes on the JMA seismic intensity scale, and the number that matters to you is the shindo reading at your location. Learn the ten levels and you can read any quake report in seconds.1
Procedures, fees, and requirements can change. Confirm current details at the Japan Meteorological Agency site.
Overview
The 震度 (shindo, "seismic intensity") scale measures how strongly the ground shakes at a specific place, on ten degrees from 0 to 7. JMA runs about 200 seismographs and collects data from over 3,600 intensity meters operated by local governments and research institutes, analyzed in real time.1
When observed intensity reaches 3 or greater, JMA issues a Seismic Intensity Information report within about a minute and a half, distributed through local governments and the media.1 That report is the trigger for rescue and relief operations, and it is also the number you should check for yourself.
Shindo vs. magnitude
Shindo and magnitude answer different questions. Magnitude (マグニチュード (magunichūdo, "magnitude")) describes the energy released by the quake itself, a single number per event. Shindo describes the shaking at your location, and it varies with distance from the epicenter and local ground conditions.1
One earthquake therefore has one magnitude but many shindo readings. A quake can record 7 near the coast, 5 in Tokyo, and 3 in western Japan. The magnitude tells scientists how big the event was; the shindo tells you what happened where you stand.
JMA assigns intensity from seismic intensity meters installed on the ground or first floors of low buildings. The phenomena tables describe what may typically be seen at each level; they are not the measurement method.2
The ten levels of shindo
The scale runs 0, 1, 2, 3, 4, 5-lower, 5-upper, 6-lower, 6-upper, then 7.1 The split of 5 and 6 into lower and upper halves exists because the damage curve steepens fast in that band.
Levels 0 to 3: recorded, slight, clearly felt
Level 0 is imperceptible to people and recorded only by seismometers. Level 1 is felt slightly by some people keeping quiet indoors. At level 2, many quiet indoor occupants feel it and hanging objects such as lamps swing slightly.2
Level 3 is felt by most people indoors and wakes many sleepers. Dishes in cupboards may rattle and electric wires swing slightly. Expect no damage; this is the level where a quake first registers as an event rather than a curiosity.2
Levels 4 to 5: alarming to damaging
At level 4, most people are startled, hanging objects swing significantly, and unstable ornaments may fall. Drivers may notice the tremor.2
Level 5-lower frightens many people, who feel the need to hold onto something stable. Dishes and bookshelf items may fall, unsecured furniture may move, and windows may break in some cases.2
Level 5-upper makes walking difficult without holding on. TVs may fall from stands, unsecured furniture may topple, and unreinforced concrete-block walls may collapse.2 Safety devices in gas meters trip around this band and stop the gas supply, and blackouts may occur.2
Levels 6 to 7: destructive
At 6-lower it is difficult to remain standing. Much unsecured furniture moves and may topple, doors may wedge shut, and wall tiles and windows may fall.2
At 6-upper, remaining standing or moving without crawling is impossible, and people may be thrown through the air. Most unreinforced concrete-block walls collapse.2
Level 7 is the ceiling of the scale. Most unsecured furniture moves and topples or is thrown, and buildings with low earthquake resistance are more likely to lean or collapse. Even high-resistance wooden houses may lean in some cases.2
| Band | Human experience | What breaks | Action cue |
|---|---|---|---|
| 0–2 | Barely felt to slight | Nothing | Note it, carry on |
| 3–4 | Clearly felt, startling | Ornaments fall | Steady objects, check information |
| 5-lower–5-upper | Frightening, walking hard | Furniture topples, walls collapse | Protect yourself, expect outages2 |
| 6-lower–7 | Standing impossible | Buildings damaged to collapsed | Full protective response2 |
Why one quake gives different readings
Intensity is the value at the station where the meter sits, and it can vary even within the same city. Underground conditions, topography, and even floor level change the shaking; upper floors of a building may amplify it considerably.2
Equal intensity also does not guarantee equal damage. Amplitude, period, and duration of the motion plus the construction type and ground beneath the building all shape the outcome.2 Two neighborhoods with the same reading can have very different damage.
Check your local intensity after a quake
JMA publishes the hypocenter, magnitude, and observed intensities immediately after each quake.1 Before the shaking even arrives, the Earthquake Early Warning system announces estimated shindo figures and the expected arrival time of the main motion.3 After shaking stops, open the JMA website or app and find the reading for the station nearest you rather than relying on the headline figure for a faraway city.
The English earthquake information pages carry the same station-level readings as the Japanese pages. Bookmark the JMA earthquake page now, before you need it under stress.1
Find your municipal hazard map
Your shindo reading tells you what just happened; your hazard map tells you what the ground beneath you can do next. Every municipality publishes hazard maps showing flood, landslide, tsunami, and other risk zones for its own neighborhoods.
Start at the national Hazard Map Portal run by the Ministry of Land, Infrastructure, Transport and Tourism at https://disaportal.gsi.go.jp/, which overlays flood, tsunami, landslide, and volcanic risk data on one map.4 Then follow the portal to your own municipality's published map, because evacuation sites and zone boundaries differ by city and ward.4 Confirm which map version your municipality currently publishes, since zone boundaries are revised over time.
Good to know
Shindo 4 in your town can mean shindo 6 one station over
Headline readings describe one station, not the whole quake. Check the station nearest your home and workplace, and remember that soft ground and upper floors shake harder than the reported ground-level figure suggests.2
Magnitude numbers do not tell you what to do
A magnitude 7 far offshore can shake your apartment less than a magnitude 5 directly beneath it. Base your response on the local shindo reading and the shaking you feel, not on the magnitude number on television.1
Intensity 5-lower trips gas meters and stops trains
Expect gas shutoffs, power outages, and suspended train service from around 5-lower upward, even when buildings are undamaged.2 Plan for an evening without gas and a commute that does not involve trains.
See also
- Gas in Japan: City Gas vs. Propane and the Safety Inspection
- Utility Activation: Electricity, Gas, Water
- The Household Earthquake-Preparedness Kit
- Earthquake Insurance (Jishin Hoken)