## 4 Simulation of the Seismicity
Table 5 shows a comparison of seismic features detected in the CPTI15 catalog, in the time interval 1650-2020, and the 100,000 years simulated catalog for the study area. In Figure 4, we show the Magnitude-Frequency Distribution (MFD) of the simulated catalog, compared with that of the 1650-2020 CPTI catalog for events above the completeness threshold magnitude of 5.0. Another metric for comparing our simulations with the real observations is given by the numbers of multiplets counted in the same time interval of 370 years (third line of Table 5) and the mean ratio between these numbers and the corresponding numbers calculated on a set of randomisations (last line of Table 5): these randomisations should effectively destroy the presence of clustering relation among the events. The obtained mean number could in our opinion represent the degree of \"clustering\" of the catalogs. The value of the ratio systematically greater than one supports the hypothesis that the occurrence of sequences containing multiple mainshocks is not just a casual circumstance. Even if this procedure can give different results changing internal criteria, these criteria are not changed while applying the procedure to the two catalogs to be compared. Figure 5 shows the distribution of the ratios between the number of multiplets identified in the 100,000 years synthetic catalog and 500 randomizations of the same catalog. The average ratio is 2.13 \(\pm\) 0.24, which denotes a good agreement between the production of multiplets of the simulated catalog with respect to that of the observations (see also Table 5). In Figure 4, we show the MFD of the simulated catalog, compared with that of the 1650-2020 CPTI catalog for events above the completeness threshold magnitude of 5.0. This figure shows that the MFD of the simulated catalog does not follow a straight line as expected according to the Gutenberg-Richter law, but exhibits a change in its slope in the magnitude range \(5.7\leq M_{w}\leq 7.0\), where the b-value decreases dramatically. This circumstance is again due to the selection of the S-R and A-R free parameters, and the boostered role of the Coulomb stress transfer adopted in this particular study, which enhances the growth of nucleated ruptures, producing a sort of characteristic earthquake model. We also performed a comparison between the annual seismic moment rate released by the earthquakes of the simulated catalog and the observed ones. Adopting [PERSON] and Kanamori [24] magnitude-seismic moment conversion formula, we computed the total seismic moment released in the simulated catalog of 100,000 years. The sum is equal to \(0.518\cdot 10^{22}\) Nm, i.e., a seismic moment rate of \(0.518\cdot 10^{17}\) Nm/year. In a similar way, we computed the seismic moment of all earthquakes of M > 5.0 listed in the observational catalog from 1650 to 2020. A value of \(1.35\cdot 10^{19}\) Nm is acquired, implying a seismic moment  
Figure 3: Map of 13,845 simulated earthquakes with \(M_{w}\geq 5.0\), obtained from 100,000 years simulation. Point opacity is proportional to number of epicenters reported in output synthetic catalog in each cell of fault. rate of \(0.365\cdot 10^{17}\) Nm/year (Table 5). In conclusion, the seismic moment rate released by the simulated catalog is about 1.4 times larger than that of the observed seismicity. This could be explained by the uncertainties in the slip-rate values assumed in our seismogenic model. We should also take into account the limited size of the earthquake catalog considered in the comparison of the observed seismic moment rate with that obtained from simulations. In fact, the duration of the 1650-2020 catalog (370 years) is shorter than the recurrence time on any of the fault segments reported in Table S1 and Figure 1. It is reasonable to hypothesize that this time window, upon which 22 events with \(M_{w}\geq 6.0\) have occurred, was characterized by a moderate seismic activity in our study area, without a significant contribution of large magnitude events.