Conjugate Rupture of the 2 April 2024 MW 7.4 Hualien Earthquake Inferred from Seismic and Geodetic Observations

The rupture process of the 2024 Hualien M_W 7.4 earthquake is determined using seismic and geodetic datasets. Joint inversion reveals a conjugate faulting scenario with rupture initiation on an east-southeast-dipping reverse fault near the 40-km deep fault intersection with a west-northwest-dipping reverse fault that began to rupture 8 s later. The slip zone on F1 extends ~60 km along strike and ~60 km along dip, while slip on F2 extends ~60 km along strike and ~40 km along dip, with overall rupture velocity of ~2.5 km/s. The heterogeneous slip distributions have a peak slip of ~2.4 m, and complementary aftershock patterns. The total seismic moment is 1.5×10²⁰ N·m, most occurring within 45 s. Depth-dependent rise time patterns are observed, with longer values at shallower depths. This study contributes valuable insights into conjugate fault interactions during collision zone earthquakes, facilitating seismic risk assessment and complex fault dynamic simulations.