**3. Some remarks on the Apennine zones most prone to the next strong earthquakes**

Taking into account the regularity patterns that we tentatively recognise in the seismic sequences so far developed (**a-g** in **Figure 4**), we try to gain insights into how the last, still ongoing, sequence (**h** in **Figure 4**) might develop in the next future. In this regard, it must be considered that the first phase of that sequence has so far involved several earthquakes in the Southern and Central Dinarides and the Southern and Central Apennines. The acceleration of southern Adria triggered by such seismic decouplings has presumably stressed and deformed the RMU wedge, increasing its tendency to separate from the inner belt. This hypothesis may explain why a number of major extensional shocks (1979 M = 5.8, 1984 M = 5.6, 1997 M = 6.0, 5.7, 5.6, 5.5, 2016 M = 6.2, 6.1, 6.6, [7]) occurred along the western border of the RMU wedge (Norcia-Colfiorito-Gubbio fault system). The NE ward acceleration of the southern RMU wedge may have emphasised stresses (and thus seismic hazard) at the northern boundaries of that wedge (Romagna fault, Alta Valtiberina trough and Rimini-Ancona thrust front). Thus, one could expect that the present seismic hazard in such zones is higher than in the other Apennine fault systems. This hypothesis is also suggested by the fact that the last significant earthquakes (M ≥ 5.3) in the above zones occurred about 100 years ago, i.e. a quiescence longer than the previous ones (**Figure 4**).

Another zone where tectonic load may currently be high is the Emilia Apennines and the related buried folds (**Figure 2**), since such structures, including the Mugello trough, have been stressed by the push of the RMU wedge during the last tens of years. The above hypothesis is consistent with the fact that intense earthquakes (2012, M = 6.1, 5.9) recently occurred in the Ferrara buried folds (lying outside the Emilian Apennines) and that moderate seismicity (M = 4.5) affected the Mugello trough on December 2019.

The kinematic field delineated by geodetic data [11, 50, 51] suggests that the separation between the inner and outer Apennine belts is developing at rates of about 3–4 mm/y, which implies that a displacement of about 30–40 cm has been accumulated since the last activations of the fault systems surrounding the northern RMU wedge (about 100 years). This displacement is comparable to the fault slip associated with a M = 5–6 earthquake e.g., [55].
