Financial Seismic Risk Analysis of Building Portfolios

The role of financial seismic risk analysis and risk quantification has grown rapidly in dealing with important risk-management decisions for building portfolios. Recent developments in regional seismicity modeling, ground-motion modeling of spatially correlated seismic effects, and seismic fragility analysis have enabled more accurate estimation of earthquake risk exposure of building portfolios. The result from quantitative seismic loss estimation can be represented by a seismic loss curve and various scalar risk metrics, such as annual expected loss, value at risk, and tail value at risk, which are all expressed in monetary terms. Their use facilitates the risk-based decision making and risk communication. This study illustrates the current risk-quantification approaches through a case study for a group of wood-frame houses in Canada. Potential pitfalls in using simple risk metrics for decision analysis on seismic risk-transfer and risk-mitigation strategies are discussed. The results indicate that the use of tail value at risk may be appropriate as it provides more consistent risk-comparison results by reflecting the expected risk of rare events.