Philosophical aspects of probabilistic seismic hazard analysis (PSHA): a critical review

The goal of this paper is to review and critically discuss the philosophical aspects of probabilistic seismic hazard analysis (PSHA). Given that estimates of seismic hazard are typically riddled with uncertainty, different epistemic values (related to the pursuit of scientific knowledge) compete in the selection of seismic hazard models, in a context influenced by non-epistemic values (related to practical goals and aims) as well. We first distinguish between the different types of uncertainty in PSHA. We claim that epistemic and non-epistemic considerations are closely related in the selection of the appropriate estimate of seismic hazard by the experts. Finally, we argue that the division of scientific responsibility among the experts can lead to responsibility gaps. This raises a problem for the ownership of the results (“no one’s model” problem) similar to the “problem of many hands” in the ethics of technology. We conclude with a plea for a close collaboration between philosophy and engineering.