What is V_S30?

V_S30 is average shear-wave velocity of the top 30 m of the earth. It is an important parameter used in classifying sites in building codes. It is widely applied in earthquake engineering, including ground-motion prediction equations, earthquake loss estimation, earthquake insurance, etc.

V_S30 is computed by dividing 30 m by the travel time from the surface to 30 m.

where d_i = the thickness of any layer between 0 and 30 m, V_si = the shear wave velocity in m/s, and the sum of d_i is 30m.

What is the SCK model?

The SCK model is a V_S30 proxy framework based on Cokriging method This framework utilizes the V_S30-topographic slope correlation in the cross-semivariogram to benefit V_S30 estimation

The benefits of V_S30 map using the SCK model.

(1) The estimation results are consistent with the measurement data;

(2) The estimation uncertainty can be represented by error variance at each unsampled location according to the spatial structure of V_S30 and topographic slope;

(3) The result map does not have artificial boundaries;

(4) The estimation results can reflect the spatial relation of V_S30 - slope and the spatial relation of local spatial environment of topographic slope.