VALIDATING THE CANADIAN SEISMIC RISK MODEL

Canada faces a scarcity of impactful earthquakes that can be used to validate seismic risk models, as the last significant damaging earthquakes occurred in the 1980s (Hobbs, Journeay, and Rotheram 2021). To overcome this limitation, this study aims to assess the reliability of the Canadian National Seismic Risk Model (CanadaSRM1) by analyzing the shaking intensities and physical impacts recorded from several recent events. These events include the 2010 Mw 5.5 Val-des-Bois and 2013 Mw 4.6 Ladysmith earthquakes in Eastern Canada, the 1985 M 6.9 Nahanni earthquake in Northern Canada, and the 2017 Mw 6.2 - 6.3 Mosquito Lake pair earthquakes in Western Canada. By evaluating the potential consequences of mentioned earthquakes in south-western Quebec, the Northwest Territories, and southern Yukon (near Whitehorse), the study aims to assess the potential impact on densely settled metropolitan areas across the country. In order to support disaster risk reduction efforts and advance the objectives of the Sendai Framework for Disaster Risk Reduction, Natural Resources Canada (NRCan) partnered with Global Earthquake Model Foundation, Italy (GEM) to develop a public Canadian Seismic Risk Model (Hobbs et al. 2023). This collaborative effort involved creating a national exposure inventory, Canadian-specific fragility and vulnerability curves, and adjusting the Canadian Seismic Hazard Model, which is the basis for the seismic provisions in the National Building Code of Canada. The risk modeling process, using GEM's OpenQuake-Engine (OQ), utilizes deterministic and probabilistic calculations to assess seismic risk at the neighborhood level for all Dissemination Areas (DAUID) in Canada. By considering baseline and simulated retrofit conditions, the model provides risk metrics such as expected immediate physical impacts, including building damage, casualties, and direct economic losses. This approach of Seismic Risk Assessment (SRA) relies on previous earthquake knowledge to estimate the potential consequences of future earthquakes, enabling the evaluation of proposed mitigation and adaptation measures for disaster risk reduction. This thesis presents a comprehensive analysis of the potential damage caused by benchmark scenario earthquakes, including shaking damage to buildings, financial losses, fatalities, and other impacts. The study utilizes the OQ Engine and the national exposure dataset, following the methodology of the CanadaSRM1. The primary findings, such as damage distributions, loss exceedance curves, and annual average losses, offer an accessible and quantifiable foundation of evidence for decision-making at various levels - local, regional, and national. These results demonstrate a high degree of consistency with observed or predicted impacts, taking into account economic and population growth adjustments. Consequently, this confirms the reliability of the first generation Canadian Seismic Risk Model, aligning it with industry standards and enabling the reproduction of recent destructive earthquakes. Given Canada's vast size, intricate seismic hazard model, and dispersed populations, this study holds unique significance. Nonetheless, the challenges faced, and solutions provided are likely to be valuable to other countries undertaking similar programs.