Logic trees, sensitivity analyses, and data reduction in probabilistic seismic hazard assessment

This article explains the essential duality between logic tree analysis and sensitivity analysis in probabilistic seismic hazard assessment. The results of a logic tree analysis can be used to carry out a sensitivity analysis. More important, a preliminary sensitivity analysis can be used to focus attention on those parameters that have the largest effects on assessed hazard. This information can be of great value in the construction of a logic tree. Thus we advocate a two-stage process that begins with a sensitivity analysis and then proceeds to the construction of a logic tree.