Comparing Slip Distribution of an Active Fault System at Various Timescales: Insights for the Evolution of the Mt. Vettore-Mt. Bove Fault System in Central Apennines

In 2016, the Mt. Vettore-Mt. Bove normal fault system (VBFS) broke during three earthquakes (Mw 6.0, Mw 5.9, and Mw 6.5), associated with clear coseismic ruptures. Based on high-resolution topography and geological field data, we determined the displacements of the VBFS. The distributions of the coseismic and postglacial displacements exhibit similar asymmetric shapes, suggesting self-similar slip profiles over the last 18 kyr. The highest displacement during the 2016 events is localized on the southern Mt. Vettore segments, the southern tip of the VBFS, which also showed the maximum throw of 32 m over the last 18 kyr yielding to a very fast throw rate of 1.6 +/- 0.5 mm/yr. Assuming a constant throw rate, the geological displacement we determined suggests an inception age of 200-250 kyr for the surface rupturing faults that ruptured in 2016 on the Mt. Vettore sector. This value can be interpreted as the minimum age for the onset of those faults in the Mt. Vettore and might result from a southward shift of VBFS activity with a change of the fault system pattern. We infer that the observed slip distribution, maximum at Mt. Vettore and tapering-off southward, might be due to the VBFS lengthening processes towards the Laga Fault and its interaction with pre-existing structure such as Olevano-Antrodoco-Sibillini thrust that might play a key role in controlling the VBFS's evolution.