ON MACROSEISMIC ATTENUATION PARAMETERS IN THE COMPARISON OF THEORETICAL SEISMIC HAZARD MAPS FOR SOUTHERN CALABRIA AND EASTERN SICILY (SOUTHERN ITALY)

For two different zonations of the Calabro-Sicilian region the macrose ismic intensity attenuation parameters are computed using the Grandori model. Some modifications to this relation are proposed here in order to allow its applicability also to those cases in which the data set available for each source zone does not present three successive epice ntral intensity levels (I-0) as required for its application. Maps of theoretical distribution of maximum expected intensities were plotted for both zonations adopted, in order to test the reliability, also usi ng other attenuation models. The results of the analysis show how the proposed modifications to the Grandori relation allow the macroseismic intensity attenuation modelling even in cases in which only one inten sity level is available. Finally, the comparison of theoretical maximu m expected intensity distribution maps, computed for different attenua tion models and seismogenic zonations, shows that the maps plotted usi ng the Grandori model and the zonation adopted by G.N.D.T. (Gruppo Naz ionale Difesa dal Terremoti - C.N.R. Italy) are more reliable.