Comment on “Comparison between probabilistic seismic hazard analysis and flood frequency analysis”

Despite providing an exceptionally clear example of the basics of probabilistic seismic hazard analysis (PSHA), Wang and Ormsbee [2005] nevertheless conclude that “…using PSHA for risk analysis is not only confusing, but is also inappropriate.” I argue here that (1) the results of a PSHA analysis are not confusing and have physical meaning, and (2) the authors' basis for declaring PSHA “inappropriate” is misguided. I note in passing that the authors consistently confuse “risk” with “hazard.” Both PSHA and flood frequency analysis provide estimates of hazard. Risk is the product of hazard, vulnerability and exposure. This discussion is only concerned with hazard.