Summary Seismic sources are typically characterized as stochastic slip distributions on complex fault geometries, which pose significant challenges for computational modelling. Source scaling laws, however, offer a streamlined alternative by correlating simplified fault geometry and slip characteristics with earthquake magnitude. So far, distinct scaling laws have been developed for different tectonic settings and fault mechanisms. However, regional variations in source parameters have not been explicitly quantified. For example, it remains unclear whether earthquakes occurring in similar tectonic environments (e.g. subduction zones) and fault mechanisms (e.g. reverse faulting), but in different regions such as Japan, South America, or Indonesia, exhibit comparable source characteristics, or how such variability should be incorporated into scaling relations. To address this gap, the present study performs a comprehensive exploratory analysis of earthquake source attributes derived exclusively from finite-fault models, including stress drop, alongside standard fault geometry and slip parameters. The analysis spans multiple groupings defined by tectonic setting, fault mechanism, seismic region, focal depth, crustal type, as well as fault-plane inversion modality and spatial resolution, which are examined to account for modelling-related variability across datasets. Stress-drop proxy and slip-parameter estimates, particularly for large magnitude earthquakes, display systematic deviations from self-similar scaling assumptions. Fault-plane modality, defined by the type of seismic and/or geodetic data used in the inversion, and fault-plane resolution, quantified by subfault discretization, are found to be associated with systematic differences in inferred slip and asperity parameters, and help explain part of the intra-event variability observed when multiple models exist for the same earthquake. These factors are therefore incorporated explicitly to isolate physical variability from modelling effects. Based on these findings, existing source scaling laws are revised using a mixed-effects regression framework. Tectonic setting, inversion modality, and fault-plane resolution are treated as fixed effects, while fault mechanism and seismic region are modelled as random and nested-random effects, respectively. The refined scaling relations provide more robust estimates of fault geometry (length, width, area, and asperity dimensions) and slip statistics (mean slip, maximum slip, and slip standard deviation), and are particularly valuable for region-specific computational source modelling and physics-based seismic hazard analysis.
Podili et al. (Sat,) studied this question.