Practical Probabilistic Seismic Risk Analysis: A Demonstration of Capability

Abstract

Smith (2005) presents a compelling argument encouraging seismologists to move beyond probabilistic seismic hazard analysis and embrace seismic risk analysis. According to Smith (2005) the results of a seismic risk analysis may take several forms ( e.g., average annualized loss or exceedance probability curves) whereby all forms can be derived from “probabilistic estimates of losses for specific portfolios of assets.” This paper demonstrates how Australian government agencies already are achieving Smith's proposal by using probabilistic seismic risk analysis (PSRA) to model earthquake risk in Australian cities. The paper provides a brief description of the process for conducting a PSRA and demonstrates typical results for two Australian cities, Newcastle and Perth, located on the eastern and western seaboards, respectively. This work has been conducted at Geoscience Australia, an Australian federal government agency, within a risk modeling group that focuses on the assessment of risk for a range of natural hazards. Experts within the group include seismologists, geophysicists, mathematicians, structural engineers, software engineers, economists, and social scientists. The work has benefited greatly from collaboration with members of the global re-insurance sector, something that also was encouraged by Smith (2005). The methodology outlined in this manuscript has been coded into a comprehensive tool for PSRA and probabilistic seismic hazard analysis (PSHA) known as the Geoscience Australia's Earthquake Risk Model (EQRM). A complete description of the approach can be found in Robinson et al. (2005), and detailed examples of the work can be found in Fulford et al. (2002) and Sinadinovski et al. (2005) for the Newcastle and Perth regions respectively. This section compares the event-based approach for PSHA and PSRA with traditional approaches for PSHA and provides a brief description of how building damage can be calculated for an earthquake scenario ( i.e., a single earthquake) using the approach adopted by HAZUS (FEMA 1999 …