Partial Ruptures, Cascading Multi‐Fault Ruptures, and Aftershocks in 2D Random Fault Network

Abstract The Gutenberg‐Richter law for the distribution of earthquake magnitude and the Omori law for the decay of aftershocks are two universal laws in seismicity. Although numerical models have been developed to reproduce these laws, they sometimes produce many more foreshocks and fewer aftershocks than observed. In this study, we numerically simulate earthquake sequences on a randomly generated 2D fault network, in which the fault lengths follow a power‐law distribution. Our simulations reproduce the Omori law with minimal numbers of foreshocks. The event size distribution follows the Gutenberg‐Richter law with the b‐value expected from the fault length distribution, despite the fact that many earthquakes are multi‐fault ruptures or partial ruptures. Partial ruptures, multi‐fault ruptures, and aftershocks are more common for denser fault systems, which have stronger fault interaction. Overall, this work illuminates how the geometrical complexity of faults produces the statistical laws of earthquakes.