Characteristics of different Mmax according to the adopted approach. Global and regional columns refer to the applicability of the method (generally speaking, geological data allow determination only in the areas where they are available). Dark and pale brown cells respectively refer to methods that give a sort of lower boundary of Mmax or a value greater than the observed one. The first 3 methods reported in Figure 2.3 furnish a sort of lower boundary to Mmax (stricter in the first case); it means that the maximum magnitude cannot be lower than the value determined in such a way. The following 3 methods, on the contrary, provide a value greater than the largest observed magnitudes; this means that special care has to be adopted when handling these values in order to avoid unrealistically high values of Mmax. All the above considerations show that the uncertainty on Mmax determination needs a careful management. In the 2008 update of National seismic hazard map of United States (Xxxxxxxx et al., 2008) a set of magnitudes with the relevant weights was defined for each seismic source zone by adopting a global analogs approach.
