Scenario-Based Seismic Risk Assessment in the Timiskaming Region of Eastern Canada

Abstract Seismic risk assessments are essential for mitigating and preparing for future seismic events and have been conducted globally, including in seismically quiet regions like eastern Canada. Although eastern Canada has relatively low seismic activity, it has experienced damaging earthquakes. Recent studies suggest that these events resulted from fault reactivation, indicating the potential for future earthquakes in the region. This article presents a scenario-based seismic risk assessment in the Timiskaming region of eastern Canada. Unlike previous studies of the region, which primarily conducted seismic risk assessments based on historical events, this study incorporated the identified causative fault of the 1935 Timiskaming earthquake, which had a moment magnitude of 6.1. The seismic risk assessment of this study was conducted on wooden buildings, as they represent approximately 90% of the buildings in the region. This study investigated the impact of two earthquake scaling relationships on fault-source characterization in eastern Canada. Because these relationships contain inherent uncertainties, rupture scenarios were generated under two conditions: (1) incorporating the uncertainties in the scaling relationships; and (2) using their median values. In the source-generation process, ruptures were either placed at the center of the fault plane or allowed to float along the plane. Additionally, the study evaluated the influence of two preferred ground-motion models (GMMs) and two site condition models on seismic risk in the region. The results indicate that the differences between the two GMMs and the two site condition models are more substantial than the differences between the two scaling relationships and the two source-generation approaches.