Exploring the seismogenic potential of the Gulf of Aqaba fault system through multi-cycle earthquake simulations

Summary Short-duration instrumental earthquake catalogues, sparsity in seismic stations, and paucity of near-source earthquake data impose strong limitations on data-driven seismic hazard assessment. In contrast, regional-scale multi-cycle earthquake simulations that generate realistic rupture scenarios provide physics-based earthquake rupture forecasts for seismic hazard assessment. In this study, we use the physics-based multi-cycle earthquake simulation engine MCQsim to compute long-term synthetic seismic catalogues that include multi-segment ruptures on a complex-geometry fault system. We expand on previous research by conducting systematic statistical analyses of synthetic earthquake catalogues for the Gulf of Aqaba (GoA, Saudi Arabia) that forms the southern extension of the Dead Sea Fault (DSF). The GoA is characterized by predominantly left-lateral strike-slip faulting and its seismic activity is revealed by past seismic swarms and large-magnitude events, including the 1995 M 7.2 Nuweiba earthquake. To address epistemic uncertainties in the seismic source characterization (SSC) of this region, we explore several modelling realisations by altering the fault system’s geometric configuration and frictional properties. Our simulations reveal that multi-segment ruptures reaching M 7.6 are possible in the GoA. The simulated catalogues reveal source-scaling properties of rupture area and stress drop consistent with global observations and empirical scaling laws. Additionally, the statistical properties of the synthetic catalogues, including the earthquake magnitude-frequency distribution, align with the short-term recorded seismicity in the study region. In summary, our simulation-based study provides insights into the GoA’s seismic behaviour through comprehensive parameter-space exploration and sensitivity analyses that document the possibility for geometrically complex, large multi-segment magnitude earthquakes.