Disaggregation of Seismic Hazard Extended to Disaggregation of Annualized Loss Ratio

Disaggregation of seismic hazard provides the relative contributions to hazards from sources of different magnitude, distance, and epsilon. It is extended in this study to the disaggregation of annualized loss ratio, which is defined as the ratio of the average total annual value loss of an ensemble of properties to the total original value of those properties. Seismic hazard is usually disaggregated with a given ground-motion value at a spectral frequency or with ground-motion values of certain mean return period and spectral frequency. Hence, the results of seismic-hazard disaggregation depend on the given ground motion. The results are very useful for engineers to select a single “design earthquake.” However, as shown herein, if the seismic sources have recurrence times very different from the mean return period of the given ground motions, their relative contributions are suppressed and may be missed completely. For some applications, such as in the residential home insurance industry, this is not desirable. The annualized loss ratio disaggregation is performed using the whole hazard curve together with the building-response curve. It does not have the limitations of being dependent on the given ground motion and may be more appropriate for some applications such as home insurance. Seismic-hazard disaggregation may be extended not only to annualized loss ratio, which is the result of the structural vulnerability exposed to hazard, but also to the measures of loss due to other hazards like liquefaction and landslide as well. Specially designed measures for losses of these hazards, similar to the annualized loss ratio for disaggregation, are needed.