| Site class | Velocity Vs, m/s | Site coefficient Fa for linear part of seismic impacts |
| A | >1500 | 0.8 |
| B | 760 - 1500 | 1.0 |
| ะก | 360 - 760 | 1.2 |
| D | 180 - 360 | 1.6 |
| E | <180 | 2.5 |