The influence of b-value estimate in seismic hazard assessment

Abstract

In any probabilistic seismic hazard assessment an important role is played by the seismicity rates. This is confirmed by the wide and controversial discussions about the procedures for their determination: Gutenberg and Richter distribution vs independent rates in every magnitude class ; size of binned magnitude class; the fitting algorithm to use (least squares or maximum likelihood); and so on. In 2004 a new probabilistic seismic hazard map of Italy, named MPS04 (MPS04 Working Group, 2004), was released adopting a logic tree approach for exploring the alternative epistemic choices (Fig. 1). For seismogenic zonation (ZS9, MPS04 Working Group, 2004) (Fig. 2) and catalogue (CPTI04; CPTI04 Working Group, 2004) no alternative models were explored.