New conditional ground motion model for permanent displacement in near-fault zones

An accurate assessment of after-earthquake permanent displacement (PD) is crucial for the anti-dislocation of structures situated across or near fault zones. The conditional ground motion model (CGMM) is an effective method for estimating after-earthquake PD. We draw on the global NEar-Source Strong-motion (NESS) database and incorporates peak ground displacement (PGD) as a secondary parameter. The model accounts for key factors such as moment magnitude (M_w), focal depth, fault type, rupture distance (R_rup), and average site shear wave velocity (V_S30). A CGMM was developed through random-effects model regression analysis to achieve a robust estimation of after-earthquake PD. The performance of the developed CGMM was validated through residual analysis, by systematically examining the influence of explanatory variables on model predictions, and through comprehensive comparisons with prior models. The results demonstrate that the developed conditional model successfully captures the attenuation trends of PD. M_w, R_rup, and V_S30 have varying degrees of impact on the model predictions; as the M_w and focal depth increase, the PD value increases. The CGMM demonstrates a pronounced near-field saturation effect. The research findings can serve as a valuable reference for the anti-dislocation design of lifeline engineering projects that cross or are in near fault zones, as well as for Probabilistic Fault Displacement Hazard Analysis (PFDHA).