| Summary: | Spatial variations in long-term (e.g. Holocene) slip rates along faults are a source of uncertainty in fault-based seismic hazard assessment (SHA), but their effect on seismicity rates and magnitude-frequency distributions remains underexplored. We conduct numerical simulations of earthquake cycles on the Parasano-Pescina normal fault in Central Italy, using multiple along-strike slip rate measurements, to investigate how spatial variations in slip rate influence slip modes, rupture extent, seismicity rates and magnitudes. We compared synthetic catalogs generated using different profiles with variable slip rates with those based on a single measurement and estimated associated ground-shaking intensities. Profiles with variable slip rate affect earthquake magnitude and recurrence by modulating stress accumulation. Highly variable slip rate profiles lead to more complex rupture patterns, including partial ruptures and slow slip events, contributing to variability in stress distribution in earthquake recurrence, magnitude-frequency distributions and ground-shaking intensities. Simplified slip rate profiles based on a single measurement produce less realistic seismic catalogues with earthquakes of characteristic magnitude and regular recurrence. This highlights the need for detailed profiles to improve SHA, particularly for faults with relatively limited rate-and-state weakening behavior and sharp along-strike gradients in long-term slip rate.
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