where a_{m} is in unknown unit, Δ = , DE is epicentral distance, H is focal depth, S is fault area and C_{0}′ = -1.23, C_{1} = 0.068, C_{2} = -0.001 and C_{3} = -0.043 (σ is not given). Note that there are typographical inconsistencies in the text, namely S_{r} maybe should be replaced by S_{al}.
Since there is no geotechnical data available, classify sites, assuming a uniform surface layer, using the predominant period of ground motions estimated using Fourier spectra to get an equivalent shear-wave velocity (mainly these are between 100 and 400m∕s).