Urban Seismic Loss Estimation by Incorporating Ground-Motion Simulation, Site Effect, and Kriging Techniques: An Application in Singapore

Regional seismic loss assessment of buildings requires ground-motion intensity measure (IM) maps. In this article, a new method to estimate the seismic structural losses of urban regions is developed. Unlike the IMs commonly predicted by ground-motion prediction equations (GMPEs), this method focuses on generating IM maps based on ground-motion simulation, site-response analysis, and geostatistical approaches. The seismic structural loss estimates are conducted for the building inventory of Singapore under a deterministic Sumatran earthquake scenario with moment magnitude (M-w) 7.7. Based on the collected soil profiles in Singapore, site-response analyses are performed using the simulated bedrock motions. Kriging techniques are utilized to produce surface ground-motion intensity maps. The structural losses are then estimated using the simulated intensity maps, and the capacity and fragility curves provided in Hazards U.S. Multi-Hazard (HAZUS-MH). The estimated structural losses by this simulation-based method are compared systematically with those obtained by the GMPE-based loss estimation method. The influence of the spatial variability of IMs on seismic loss estimates is also discussed. The simulation-based approach can account better for small-scale variability of site conditions. It is applicable to urban regions where adequate attention should be paid to site effects.