Sensitivity analysis of Eastern Canada High Resolution Seismic Hazard Maps to the Ground Motion Prediction Equations

English Abstract:

Eastern Canada has been known as a region, where detailed source characteristics and wave propagation properties of particular active fault sources are generally unavailable. However, several generations of the source zones models, earthquake occurrence patterns and ground motion relations have been developed to quantify seismic hazard characteristics in the region. The variety of proposed models increases the resulting level of uncertainty and results in potential error in the decision making process, related policies and standards. As a result, there is a strong interest in the sensitivity analysis of hazard maps as they relate to the main input parameters for seismicity rates and ground motion prediction equations (GMPEs) in order of total possible uncertainty estimation. Atkinson et al. 2011 investigated the effect of seismicity models and new GMPEs on seismic hazard assessment for four Canadian cities and concluded that the selection of correct GMPEs model has an important effect on the resulting hazard assessment. Our motivation in this study is not a re-evaluation of seismic hazard in Canada, but is to expand the boundaries of the GMPEs sensitivity analysis. Here, three sets of representative GMPEs (the medium, low and high) developed by Atkinson, 2013 have been used as an input for ground motion estimation for eastern crustal, western crustal, interface, inslab and offshore events and all for B/C site conditions (Vs30=760 m/s). The sensitivity analysis performed with different sets of assumed weights for the low, medium and high equations of the representative GMPEs. The analysis is complicated by the fact that for high-resolution map calculations must be carried out on a large number of sites, a process requires powerful computational resources. Here, high-resolution hazard maps production in real-time are made possible using corrections in EqHaz1 and EqHaz2 Fortran source programs developed by Assatourians et al., 2012. These are compiled into system object libraries and used as IBM InfoSphere Streams operators to implement the base PSHA procedures and functions in the streaming environment and to overcome EqHaz limitations by pipelining. The number of records in the synthetic catalog are increased up to 10,000,000 records and number of sites for hazard maps are stepped up to 2,500,000 sites.