Magnitude vs Shindo: what is the difference?
Magnitude describes the size of an earthquake at its source; Shindo describes shaking at a place. Learn why they are not interchangeable.
A JISHINDESU editorial guide based on the cited official and primary materials. It does not replace official safety information.
Frequently asked questions about magnitude and Shindo
Can magnitude be converted into Shindo?
No. Magnitude describes the size of the earthquake at its source, while Shindo describes shaking measured at a particular place. Depth, distance and local ground conditions mean that the same magnitude can produce different Shindo readings.
How many Shindo values can one earthquake have?
One earthquake can have a different Shindo value at every reporting station. Maximum Shindo is only the highest observation included in the report.
Does maximum Shindo describe shaking where I am?
Not necessarily. To understand local shaking, check the measured value for a nearby municipality or observation station instead of relying only on the report maximum.
On this page
One source, many observations
Magnitude describes the size of the source and is one value within a report. Shindo is local intensity, so an earthquake has many Shindo observations — one at each reporting station.
In shorthand, magnitude answers “how large was the earthquake?” while Shindo answers “how strongly did it shake here?”.
Magnitude is logarithmic
Magnitude is logarithmic. For amplitude-based scales, an increase of 1 represents roughly ten times the amplitude after the method's corrections, including distance. It does not mean ten times stronger shaking at your home and is not a universal definition of every scale, such as Mw. A standard approximation relates an increase of 1 magnitude unit to about 32 times the energy radiated as seismic waves. Shindo still describes local shaking intensity.
Reports may identify a magnitude type. Methods suit different data and event sizes, and a preliminary value can be revised after further analysis.
A smaller shallow event can feel strong nearby
A shallow event close to a city can produce high local Shindo despite moderate magnitude. A larger, deeper or distant event may be noticed across a broad area but create weaker shaking at one particular place.
Magnitude, depth, hypocentre and station observations should therefore be read together. Magnitude alone cannot describe what happened on a specific street.
The same magnitude does not mean the same shaking
Imagine two earthquakes with the same magnitude. One is shallow and directly beneath a built-up area; the other is deeper and far from a city. Their source sizes may be similar, but nearby stations are likely to record different Shindo.
Readings can also vary within one event. A station on soft sediment may record stronger or longer motion than one on firmer ground. Wave direction and distance from the full rupture matter too—not only distance from the epicentre marker on a map.
Which number should you use?
Use magnitude to compare the overall size of earthquakes. Use observations from the nearest real stations to understand shaking in Kawasaki, Chiba or another locality.
Do not convert maximum Shindo into magnitude or the reverse. They describe different properties and there is no universal conversion table.
A practical order for reading a report
Start with the time and location to make sure you have the right event. Then check magnitude and depth: they describe the source and help you compare it with other earthquakes. Finally, open the Shindo observations and find the municipality or station nearest to the place you care about.
Treat maximum Shindo as a summary of the report, not as your local result. If no nearby station appears, do not assume Shindo 0. That point may be absent from the bulletin or its data may not have arrived yet.
- Magnitude: how large was the earthquake at its source?
- Shindo: how strongly did the ground move at a particular station?
- Depth and distance: why did the same event feel different from place to place?