Abstract
Abstract
Forecasting earthquakes is fraught with challenges. We quantify the magnitude and spatial variability of interseismic coupling (locking) on fault systems, which then informs the system's future seismic potential. The June 24, 2026 Mw 7.2 and Mw 7.5 Northern Venezuela earthquake doublet provides an opportunity to test this framework. The earthquakes resulted in up to 6300 deaths and US $37 billion in direct damage. Quantifying the post-earthquake seismic hazard is essential. If the strain released during the earthquakes reconciles with the pre-2026 accumulated strain, then the faults involved pose no near-term seismic hazard. The earthquake doublet occurred on the Bocono and San Sebastian faults, the main faults accommodating the relative motions between the Maracaibo Block, the South American Plate, and the Caribbean and South American plates (CA-SA), respectively. Here we show, using satellite radar interferometry, that interseismically locked portions of both faults participated in the earthquake doublet, recovering nearly all interseismic strain accumulation. We further document that the El Ávila Fault, which accommodates up to 5 mm/yr of CA-SA motion near Caracas, is partially locked, and the imparted Coulomb Failure Stress following the doublet would delay a future rupture. Nevertheless, the fault remains a significant hazard.