Uncertainty in PSHA related to the parametrization of historical intensity data

Abstract. In recent times a great deal of research aimed to reduce of uncertainties in probabilistic seismic hazard analysis (PSHA). Most attention was paid to the role of ground motion prediction equations (GMPEs; see, e.g., Strasser et al., 2009), while no studies were devoted to a possible larger source of uncertainties: the historical catalogues of earthquakes.

In areas where historical catalogues provide a record many centuries long and surface geology does not permit us to obtain complete catalogues of seismogenic faults at the moment, their use is unavoidable for estimating seismicity rates required for PSHA. Their use is also gaining popularity as an independent tool for the estimation of PSHA (D'Amico and Albarello, 2008) and for validation purposes (Stirling and Petersen, 2006; Mucciarelli et al., 2008).

After proposing an alternative parametrization of historical macroseismic intensity, this paper is devoted to discussing what the real impact of starting uncertainties in intensities on the final uncertainties in PSHA is.