- Ground-motion model is:
where X(M,Δ,GC

_{i}) is in gal, c = -1.218, for group 1 sites a(GC_{1}) = 987.4, b(GC_{1}) = 0.216 and σ = 0.216, for group 2 sites a(GC_{2}) = 232.5, b(GC_{2}) = 0.313 and σ = 0.224 and for group 3 sites a(GC_{3}) = 403.8, b(GC_{3}) = 0.265 and σ = 0.197. - Use three site categories:
- Group 1
- Tertiary or older rock (defined as bedrock) or diluvium with H < 10m or fundamental period
T
_{G}< 0.2s. - Group 2
- Diluvium with H ≥ 10m, alluvium with H < 10m or alluvium with H < 25m including soft layer
with thickness < 5m or fundamental period 0.2 < T
_{G}< 0.6s. - Group 3
- Other than above, normally soft alluvium or reclaimed land.

- Only includes free-field records with M
_{JMA}≥ 5.0 and focal depths D_{p}< 60km. Excludes records from structures with first floor or basement. - Records instrument corrected, because Japanese instruments substantially suppress high frequencies, considering accuracy of digitization for frequencies between and 12Hz.
- Note that M
_{JMA}and Δ not necessarily most suitable parameters to represent magnitude and distance but only ones for all records in set. - Note lack of near-field data for large magnitude earthquakes, approximately of records from M
_{JMA}< 7.0. - Use 30km in distance dependence term because focal depth of earthquakes with magnitudes between 7.5 and 8.0 are between 30 and 100km so 30 is approximately half the fault length.
- Try equation: log X = f
_{1}+f_{2}M +f_{3}log(Δ+30)+f_{4}D_{p}+f_{5}M log(Δ+30)+f_{6}MD_{p}+f_{7}D_{p}log(Δ+30)+ f_{8}M^{2}+ f_{9}{log(Δ + 30)}^{2}+ f_{10}D_{p}^{2}where f_{i}are coefficients to be found considering each soil category separately. Apply multiple regression analysis to 36 combinations of retained coefficients, f_{i}, and compute multiple correlation coefficient, R, and adjusted multiple correlation coefficient, R^{*}. Find that inclusion of more than three coefficients does not give significant increase in R^{*}, and can lead to unrealistic results. Conclude due to insufficient data. - Consider a, b and c dependent and independent of soil type and examine correlation coefficient, R, and
adjusted correlation coefficient, R
^{*}. Find that c is not strongly dependent on soil type. - Find match between normal distribution and histograms of residuals.