We examine 257 finite-fault rupture models for 135 moment magnitude (Mw) 4.1 to 8.1 continental earthquakes to estimate how many source faults ruptured in each earthquake. We use fault geometries and rupture kinematic criteria to estimate fault populations. The minimum observed Mw for multi-fault rupture is 6.0. Approximately ~37% of the 135 earthquakes investigated were sourced from multi-fault ruptures. Upper-bounds and variance of fault rupture populations increase with increasing Mw. Fault rupture populations show no dependency on strain rate or proximity to plate boundaries. Coulomb stress modelling provides useful insights into why many earthquakes exhibit complex multi-fault rupture characteristics, and how this influences earthquake Mw maximum estimations and shapes of earthquake frequency-magnitude distributions. The 2016 Mw 7.8 Kaikoura earthquake is amongst the most complex multi-fault earthquakes ever recorded.
