- Ground-motion model is:
where a is in gal, for M

_{L}≤ 6 b_{1}= 0.318 × 29^{1.14b}, b_{2}= 1.03, b_{3}= 1.14 and σ = 0.930 (in terms of natural logarithm) and for M_{L}> 6 b_{1}= 26.0 × 29^{1.22b}, b_{2}= 0.432, b_{3}= 1.22 and σ = 0.592 (in terms of natural logarithm). - Assumes all earthquakes have focal depth of 8km.
- Makes no distinction for site conditions in first stage where uses only earthquake records.
- Studies effects of PGA cutoff (no cutoff, 0.01, 0.02 and 0.05m∕s2), distance cutoff (no cutoff and < 150km) and magnitude cutoff (all, ≥ 5, ≥ 6, ≥ 6, ≥ 6 and ≤ 6).
- Selects 6 as optimum magnitude cutoff but uses all data to derive equation for M
_{L}≤ 6 because not much difference and dispersion is slightly lower (in terms of ±1 standard deviation have 2.53 and 2.61). - In second stage uses only records from underground nuclear explosions, consistent with natural earthquake records, to derive site factor.
- Uses 1911 alluvium and 802 rock records and derive PGA ratio of alluvium to rock assuming their PGAs equal at 4km.
- Finds site impedance ρV
_{s}, where ρ is density and V_{s}is shear-wave velocity under site, is best measure of site condition. Use 2000fps (600m∕s) as shear-wave velocity of alluvium stations. - Multiplies equation (after taking logarithms) by = log
_{10}(ρV_{s}) and normalise to 4km. - Notes may not be a good model for other regions.