1 Introduction Every time we summarize results in a long chain of analyses, we gain in simplicity, but we lose in resolution. Whether this loss is important or can safely be disregarded, is both case- and application-specific. For the probabilistic calculations and Monte Carlo simulations that characterize any seismic risk assessment task, the effect of the summation process on the final outcome remains to be investigated. Consider, for instance, a portfolio of spatially distributed assets.
