- Ground-motion model is:
where A is in cm∕s2, b

_{0}= 2.305, b_{1}= 0.178, b_{2}= -0.666 and b_{3}= 30 (σ not reported^{7}). - Use N-value profiles from standard penetration tests (SPTs) to characterise sites. Use data from alluvial
and diluvial sites. Exclude data from rock and very soft soils. Define S
_{n}as a weighting function for SPT profile to characterise softness of surface layers. Plot residuals from model against S_{n}and find correlation. Derive site correction factors for model. Find coefficient of variation decreases after applying correction. - Use 346 uncorrected components (magnitudes from 5 to about 7.8 and r
_{epi}from about 7 to 500km) to derive preliminary model without site term: = b_{0}10^{b1M}∕(r_{epi}+30)^{b2}. Derive models using different data selections: all data, M < 6.6, M ≥ 6.6, r_{epi}≤ 119km, r_{epi}> 119km, M-r_{epi}region where expected PGA (from model using all data) ≥ 39cm∕s2 or expected PGA < 39cm∕s2 (these selected divide data into two equal halves). Examine scaling of the various models in 3D plots. Based on this analysis, conclude that model depends on M-r_{epi}range used for data selection. Because of engineering interest in PGA> 10gal believe model should be derived using M-r_{epi}region defined by expected PGA. - 18 records from 1978 Off Miyagi earthquakes and 6 records from 1978 Izu-oshima-kinkai earthquake.
- Strong correlation between M and r
_{epi}with almost all data from M > 7 being from r_{epi}> 100km. - Try different b
_{3}values but find influence on coefficient of variation minimal so fix to 30km. - For final model use corrected accelerograms (PGAs generally 10% to 30% higher than uncorrected values). Most data from SMAC instruments.
- Plot residuals w.r.t. r
_{epi}and M and find no trends.

^{7}Report coefficient of variation of 0.578 which could be the value of σ in terms of natural logarithms.