The JMA (Japan Meteorological Agency) seismic intensity scale, which indicates the strength of the seismic motion, is measured on a seismic intensity meter. This chart gives examples of situations and damage which may be caused by the seismic motion at each seismic intensity. The following points should be noted in using this chart:
1 The seismic intensity announced by the JMA is the value obtained from a seismic intensity meter, and is not determined from the phenomena described in this chart.
2 Sites where equal seismic intensity were observed would not necessarily suffer the same degree of damage, because the amount of dansage depends on the condition of structures and on the nature of the seismic motion. This chart describes some typical situations which may occur. Actual damage may be greater or less than that described in the chart.
3 The intensity of seismic ground motion is greatly influenced by subterranean structure and topography. The seismic intensity is a value observed at a site where a seismic intensity meter is installed. The seismic intensity occasionally varies even within a city. The seismic intensity is usually measured at ground level, and in general the shaking on the upper floors of buildings may be amplified.
4 A large earthquake generates long-period seismic waves. Even at locations far from the epicentre, where the seismic intensity is rather low, the long- period waves may occasionally cause some peculiar damage, such as the sloshing of oil in a tank, or trouble with elevators
5 This chart has been prepared mainly from examples collected from recent destructive earthquakes. The chart is subject to revision when new examples are collected or the descriptions given here become inconsistent with actual events due to improvement in the earthquake-proofing of buildings, etc.
