- Four Ground-motion models:
_{1}= 1.000, c_{2}= 0.333, d = -1.270 and σ = 0.154, for model III a = -2.000, b = 0.270, c_{1}= 0.968, c_{2}= 0.312, d = 0.160, e = -0.0105 and σ = 0.175 and for model IV a = 1.009, b = 0.222, d = -1.915 and σ = 0.174. - Note 25 in Model IV should not be assumed but should be found by regression.
- Note tectonics and travel paths may be different between N. American and foreign records but consider additional information in near field more relevant.
- Selection procedure composite of Campbell (1981) and Joyner and Boore (1981). Exclude data from buildings with more than two storeys.
- Weighted least squares, based on distance, applied to control influence of well recorded events (such as San Fernando and Imperial Valley). Similar to Campbell (1981)
- Test assumption that logarithm of residuals are normally distributed. Cannot disprove assumption.
- Variability between models not more than ±20% at distances > 10km but for distances < 1km up to ±50%.