Site Class

Description of soils (in reduced form)

Characterization of seismic properties of soils

The estimated seismic intensity of the site under seismic region

Seismic rigidity

r×V_s

(g/cm³×m/s)

Shear wave V_s, m/s

Ratio V_p/V_s

VI

VII

VIII

IX

I

Rocky ground (including permafrost eternally frozen); coarse soils are dense, slightly wet

>1500

>700

1.7 - 2.2

-

VI

VII

VIII

II

Rocky soils weathered; the coarse-grained soils, with the exception referred to the first category, sand gravel, large and medium size dense and the average density slightly wet and moist

350 - 1500

250-700

1.7 - 2.2(dry)

2.2 - 3.5 (wet)

-

VII

VIII

IX

III

Sand dense and medium density water-saturated

200 - 350

150 - 250

3.5 - 7

VII

VIII

IX

>IX

IV

The most dynamically unstable sandy-clay soils are prone to liquefaction under seismic loads

<200

60 - 150

7-15

VII*

VIII*

IX*

>IX*