Empirical Scaling Relationships Between Fault Length and Throw‐Rates Modulated by Fault Interactions in Extensional Regimes

Throw rates of active faults are expected to scale with fault length because the geometric moment of a fault is directly related to its dimensions. However, empirical data sets commonly display substantial scatter, which limits the use of fault scaling relationships for seismic hazard assessment and for understanding the mechanics of continental deformation. Here we compile and investigate throw‐rate versus fault‐length data sets from three extensional regions in Italy characterized by progressively increasing numbers of active faults across strike. For each region, we quantify the strength and scatter of the scaling relationship using multiple statistical metrics, including R2, RMSE, and SSE. Our results show that the strength of the correlation systematically decreases and scatter increases as the number of across‐strike faults increases. This pattern is robust across statistical measures and is not significantly affected by uncertainties in fault length or throw‐rate estimation over Holocene to Late Quaternary timescales. We interpret these observations as evidence that fault interaction within densely faulted systems plays a first‐order role in controlling throw‐rate variability. These findings have important implications for the application of fault scaling relationships to seismic hazard assessment and for models of strain partitioning in continental extensional settings.