Specifies the soil type.
I - Hard Soil
Ground deposits formed exclusively by layers with propagation velocity b0 = 700 m/s or modulus of rigidity ³ 85000.
II - Medium Soil
Ground deposits with fundamental period of vibration and effective velocity of propagation which meets the condition Bc Ts + Bs Tc > Bc Tc.
III - Soft Soil
Ground deposits with fundamental period of vibration and effective velocity of propagation which meets the condition Bc Ts + Bs Tc < Bc Tc.