From: Seismic microzonation of a region with complex surficial geology based on different site classification approaches
Site class
Description
Site period
NEHRP site class
Hard rock
A
SC I
Rock
T0 < 0.2 s
A + B
SC II
Hard soil
0.2 ≤ T0 < 0.4 s
C
SC III
Medium soil
0.4 ≤ T0 < 0.6 s
D
SC IV
Soft soil
T0 ≥ 0.6 s
E + F