Boomerang Earthquakes Don’t Need Complex Faults

A boomerang earthquake starts at one edge of a fault (yellow star) and initially ruptures in one direction (yellow to red crescents). After propagating forward, a secondary rupture travels backward through the already ruptured area (red crescent moving left), an effect that can increase ground shaking on geometrically simple faults. Credit: Sun and Cattania [2026], Figure 1