Effects of Seismicity Models and New Ground-Motion Prediction Equations on Seismic Hazard Assessment for Four Canadian Cities

Seismicity rates and ground-motion prediction equations (GMPEs) are the key uncertainties in probabilistic seismic hazard analysis (PSHA). We explore the impact of new findings and knowledge from seismological and ground-motion studies on seismic hazard assessment for eastern and western Canada. Updated information includes the reevaluation of seismicity rates and their interpretation in terms of seismic source zones and the use of new GMPEs. We refer to our model as an interim updated seismic hazard model, as it does not treat all uncertainties comprehensively; rather, we address the impact of key uncertainties. Based on our updated interim seismic hazard model, uniform hazard spectra (UHS) at four major cities across Canada are obtained and compared with UHS in the current seismic hazard maps of Canada (2005/2010), which are based on a 1995 seismic hazard model developed by the Geological Survey of Canada. Sensitivity analysis highlights the significant impact of seismicity smoothing in low-to-moderate seismic regions (eastern Canada), while GMPEs are important for all regions. Moreover, our interim updated seismic hazard model can readily produce seismic hazard curves as well as seismic hazard deaggregation results for various site conditions and for multiple probability levels; this capability is essential for carrying out advanced earthquake engineering analyses.