Earthquakes Source Scaling at Subfault Scales

Margarita M. Solares-Colón , Diego Melgar 

Establishing scaling laws for large earthquakes remains challenging due to the heterogeneity of methodologies and datasets used to produce finite-fault models. In this study, we analyze source properties for 264 earthquakes using the NEIC finite-fault database, expanding previous efforts by examining rupture behavior over a broader magnitude range and capturing both established scaling trends and variability at the subfault scale. In general, pulse-like ruptures are favored over propagating crack-like ruptures with shorter rise times. At the subfault scale, the common assumption of rise time (τ ∝ √s) is not sustained by the observations and slip rate strongly correlates with slip. These findings are significant because pulse-like ruptures, characterized by shorter rise times and higher slip rates, have important implications for the resulting ground motions, potentially affecting regions farther from the source depending on where slip is concentrated. These local variations are important for earthquake modeling and can improve downstream applications such as rupture simulations, thereby advancing our understanding of earthquake processes.