Development and Application of Earthquake Scenarios for Risk Assessments

For individual sites, earthquake ground motions are typically determined using probabilistic seismic hazard analysis, which yields the annual frequency of exceeding specific ground motion thresholds. This data can be integrated with asset performance at varying ground motion levels to establish annual rates of outcomes, such as incipient or severe damage. When evaluating multiple locations, ground shaking maps are employed to analyze system performance; however, these maps are generally based on scenarios defined by fault source and magnitude and lack an associated annual frequency. Despite this limitation, scenario-based mapping is prevalent due to the complexity of multi-site and multi-asset assessments. It is crucial to account for spatial correlation in ground motion when multiple sites are analyzed concurrently. Moreover, considering various asset types may necessitate alternative, correlated intensity metrics. The presentation introduces a novel method for developing suites of scenario maps with consistent hazard representation across regions. The maps capture spatial and intensity measure correlations, while also approximating the target hazard. The impact of this methodology will be evaluated by comparing risk assessments derived from different approaches.