Physics-based assessment of earthquake potential and ground motions in the Gulf of Aqaba

The Gulf of Aqaba (GoA) fault system constitutes the southernmost segment of the Dead Sea Transform Fault (DSTF) and forms a ~180 km long left-lateral strike-slip plate boundary separating the Arabian Plate from the Sinai microplate.  As the most seismically active region of the Red Sea, the GoA has hosted multiple large historical earthquakes and poses significant seismic hazards to surrounding coastal communities. Increasing tourism activity and the infrastructural giga-project NEOM of the Kingdom of Saudi Arabia in the vicinity of the GoA, highlight the need for advanced seismic hazard assessment (SHA). However, the offshore nature of the fault system and limited availability of observational data complicate the efforts. 

To assess earthquake potential and seismic hazard in the region, we construct multiple realizations of three-dimensional, multi-segment fault models representing alternative configurations of the GoA fault system. We constrain variations in 3D fault geometry with  recent high-resolution multibeam imaging and local seismicity, while explicitly accounting for uncertainties in seismogenic depth, initial stress conditions, and fault roughness. Incorporating off-fault plasticity along with realistic topography and bathymetry, we perform dynamic rupture simulations with varying hypocenter locations to investigate mechanically plausible rupture scenarios and the resulting ground motions in the GoA. Our physics-based simulations show that all considered model uncertainties, especially the fault geometry, prestress condition and hypocenter location, can strongly influence rupture dynamics, cascading, and segment interactions, determining how and if rupture propagates across the multi-segment GoA fault system. Beyond characterizing earthquake potential on individual fault segments, the simulations indicate that events as large as Mw 7.6 are possible if rupture extends along the full north–south length of the fault system. The resulting synthetic ground motions show attenuation properties consistent with empirical ground motion models, but display highly heterogeneous spatial patterns, including strong rupture-directivity effects during subshear propagation and pronounced off-fault Mach-front amplification for supershear rupture that significantly enhance ground shaking in coastal communities along this narrow gulf. These results underscore the substantial seismic hazard posed by large, dynamically complex earthquakes in the Gulf of Aqaba region and highlight the value of physics-based simulations in enhancing and complementing seismic hazard assessments.