Fig. 8
Values of a DNL, b ADNL, and c PNL for the 33 stations versus the recorded PGAs and PGVs during the Wenchuan Earthquake including empirical relationship fitting. The dashed lines indicate the threshold of DNL, ADNL, and PNL proposed in this study (i.e., 4.0, 0.2, and 7%) beyond which the site response exhibits evident nonlinear behavior. The shaded areas indicate the regions covering the values of DNL (or ADNL, PNL) and PGA (or PGV) beyond their thresholds. The PGA and PGV thresholds are proposed to be 200 cm/s2 and 15 cm/s, respectively