- See Section 2.291.
- Response parameter is pseudo-acceleration for 5% damping.
- Coefficients developed through iterative process of performing regressions for entire spectral period range
with some parts of model fixed, developing smoothing models for these coefficients with period, and then
repeating analysis to examine variation of remaining coefficients. Note noticeable steps in c
_{1}at 0.8, 1.1, 1.6, 4.0 and 8.0s, where there is large reduction in usable data. Suggest that this could indicate bias due to systematic removal of weaker motions from data set. To correct this bias and to smooth c_{1}impose smooth variation in slope of c_{1}w.r.t. period. Also examine shape of displacement spectra for M ≥ 6.5 to verify that constant displacement reached at periods expected by design spectra.