Abstract Pull‐apart basins (PABs) commonly develop within extensional step‐overs along strike‐slip faults, but their effect in determining rupture behaviors across step‐overs remains obscure. Constrained by field observations, we design parallelogram‐shaped PAB models and conduct three‐dimensional dynamic rupture simulations under uniform and depth‐dependent stress regimes. Our results show that PABs greatly enhance rupture jumping capability across step‐overs, especially for the 8 km‐depth deep basin models, the average basin depth of the Dead Sea Basin. The PAB reduces the critical nucleation length and promotes rupture nucleation on the second fault, particularly under depth‐dependent stress with lower strength. We identify three different patterns of average rupture velocity distribution on the second fault, correlated with different source time function patterns. Localized super‐shear patches are commonly observed on the second fault in the depth‐dependent regime, where secondary‐fault nucleation shows a clear dependence on the overlap distance. The stopping phase at the termination of the main fault plays a critical role in rupture jumping capability across step‐overs. In the presence of PABs, the basin amplification effect, together with a secondary contribution from the bi‐material interface, further enhances jumping capability, since both the main fault and the second fault are embedded in bi‐material media at the PAB region. We also discuss a conceptual evolution‐based PAB model incorporating the Y‐shape flower structure fault geometry, highlighting its potential in explaining the large rupture jumping distance observed in natural fault systems.
Lu et al. (Sun,) studied this question.