Seismic fragility functions for earthquake-induced landslide risk assessment using identified optimal earthquake intensity measures

Abstract

Seismic fragility analysis can relate the probability of unsatisfactory performance of slopes with increasing intensity of ground motions, which is the basic component of landslide hazard risk assessment. Determination of the optimal earthquake intensity measure (IM) is one of important prerequisite for seismic fragility analysis. Although a small number of studies have already performed seismic fragility analysis of slopes, the optimal IM for seismic fragility analysis of slopes have not been discussed and researched. In the present study, 15 IMs and two different engineering demand parameters (EDPs), including factor of safety (FOS) and Newmark permanent displacement (NPD), are selected for probabilistic seismic demand and seismic fragility analysis of slopes. The metrics of correlation, practicality, efficiency, and proficiency are adopted to identify the optimal earthquake IMs among the studied 15 IMs for two EDPs in seismic fragility analysis of slopes respectively. The results have found that the optimal IM is different for slope fragility analysis when different EDPs are selected. Acceleration spectrum intensity is the most optimal IM among the examined 15 IMs for seismic fragility analysis of slopes when FOS is adopted as the EDP. When NPD is selected as the EDP, root mean square of acceleration and velocity spectrum intensity are in general more appropriate than other IMs. In the last, the seismic fragility curves with regard to two EDPs and corresponding optimal IMs are derived for interpreting more properly slope seismic performance and earthquake-induced landslide risk.