Empirical evidence for acceleration-dependent amplification factors

Incorrect versions of Figures 5 and 6 containing nor-malization errors were accidentally published by Borcherdt (2002). They should be replaced with the figures shown here. The text and tabulated regression values published in Borch-erdt (2002) are correct and refer to the figures shown here. Figure 5. Borcherdt—Average spectral ratio for the short-period band for site class D (a) and site class C (b). The empirical data as derived using the hypocentral distance norm and the Abrahamson and Silva (A&S) spectral norm at 0.3 sec are plotted on each figure. Corresponding regression curves, 95 % confidence limits for the observed values, and the 80 % confidence limits for the ordinate to the true population regression line are shown. 374 Erratum Figure 6. Borcherdt—Average spectral ratio for the mid-period band for site classes D and C. The empirical data as derived using the hypocentral distance norm and the Abra-hamson and Silva (A&S) spectral norm at 1.0 sec are plotted on each figure. Corresponding regression curves, 95 % confidence limits for the observed values, and the 80 % confidenc