- Ground-motion model is:
_{1}= 0.237, b_{2}= 0.229, b_{3}= 0, b_{5}= -1.052, b_{6}= 0.174, h = 7.27km and σ_{log Z}= 0.203 (see Spudich and Boore (2005) for correct value of σ_{3}for use in calculating σ for randomly-orientated component). - Use two site classes:
- Γ = 0
- Rock: sites with soil depths of < 5m.
- Γ = 1
- Soil

- Use data of Spudich et al. (1999).
- Correct equations of Spudich et al. (1999) for 20% overprediction of motions for rock sites, which was
due either to underestimation of shear-wave velocities for rock sites for extensional regimes (believed to
be more likely) or an overestimation of shear-wave velocities at soil sites. Correction based on adjusting b
_{1}and b_{6}to eliminate bias in rock estimates but leave soil estimates unchanged. - Verify that adjustment reduces bias in rock estimates.
- Do not change σ
_{log Z}because changes to b_{1}and b_{6}have a negligible influence on σ_{log Z}w.r.t. errors in determining σ_{log Z}.