Kinematic evolution of the Northern Red Sea Region inferred from probabilistic moment tensor summation

We present a probabilistic assessment of present-day crustal deformation by integrating seismic moment-tensor summation with nonparametric bootstrap resampling of focal mechanisms and seismicity parameters across three distinct zones: The Gulf of Suez, the northern Red Sea axial rift, and the Gulf of Aqaba. By explicitly propagating uncertainties associated with focal-mechanism geometry (strike, dip, rake) and seismicity parameters (a, b-values, and Mmax), we derive statistically robust moment, strain-rate, and model-equivalent velocity tensors for each domain. The results reveal weak but measurable seismic deformation in the Gulf of Suez (strain-rate magnitude ~ 10−7 yr−1), still lower and more heterogeneous extension in the northern Red Sea (~ 10−9 yr−1), and the strongest strike-slip to transtensional deformation in the Gulf of Aqaba (~ 10−6 yr−1). These tensors are independently corroborated by published focal-mechanism stress inversions, with which they share consistent deformation styles and principal-axis orientations. Although seismicity may occur due to stress transfer or reactivation triggered by earthquakes from adjacent active source zones, the results indicate a regional transition from an earlier Red Sea–Suez rifting phase toward markedly decelerated rifting in both the Gulf of Suez and the northern Red Sea, while active deformation localizes along the Gulf of Aqaba. The systematic discrepancy between seismic and geodetic deformation indicates that a substantial fraction of the total plate-boundary strain is accommodated aseismically through fault creep, dyking, and viscous lower-crustal flow, with direct implications for seismic hazard assessment across the region. Bootstrap convergence diagnostics confirm stable resolution of the dominant deformation style in each tectonic domain while preserving physically meaningful uncertainty where deformation is intrinsically weak or heterogeneous. Collectively, these results demonstrate that the Sinai triple junction operates as a diffuse plate boundary in which deformation is strongly partitioned between transform shear, waning rifting, and weakly coupled axial extension, with aseismic processes playing a key role in accommodating plate motions. The velocity tensors are treated as model-equivalent kinematic quantities derived from the seismic moment budget and are therefore interpreted together with the moment and strain-rate tensors, rather than as direct GPS-equivalent opening or slip rates

Chokri Jallouli

Kinematic evolution of the Northern Red Sea Region inferred from probabilistic moment tensor summation