The SI value (or spectral intensity) is equivalent to the magnitude of

the destructive energy imposed by seismic motion on structures.

The SI value, which is the average value of the integrated velocity

response spectrum, is an index that expresses the destructive force of

seismic motion and is highly correlated with the damage to structures.

SI =

Sv( T,h)dT

∫

2.4

1

2.5

0.1

SI value

formula

What Is an SI Value?

Relationship between SI Value and

Measured Seismic Intensity Equivalent Value

Vibration Sensors D7S

7

6

5

4

3

1.0

10.0

100.0

SI value (kine): Logarithmic axis

Seismic intensity scale of Japan

D7S

Compact & High-precision Seismic Sensors

- Reducing Secondary Disasters from Earthquakes -

2