JMA Seismic Intensity Scale:
Numerical value for the scale of shaking.
In Japan, a scale of 10 is used to describe.
JMA comes from each observation point.
Magnitude / Richter Scale:
Numerical value representing the energy (size) of the earthquake itself.
Magnitude is only one number for each earthquake, coming from epicenter.
Japan Metrorological Agent （JMA）Seismic Intensity Scale information
If the magnitude is large but the epicenter is distant or deep, the ground will not shake much and the intensity will be small if the magnitude is small but the epicenter is close or shallow, the ground will shake and the intensity will be large.
However, that these two figures are only “indices” and the scale of the earthquake is not proportional to the size of the figure.
Also JMA dos not increase in relation to he magnitude of the earthquake.
Japan uses the JMA Seismic Intensity Scale to show how strongly an earthquake is felt, how strongly the ground shakes and how people and buildings are actually affected in each area.
Magnitude tells us how big an earthquake is, but intensity tells us what people actually experience on the ground.
It’s an easy way for residents in the affected areas to take disaster prevention action.