Quantifying crustal stress in the Sinai Peninsula caused by gravitational potential energy and its tectonic implications

This study uses numerical models of topography and Moho depth to quantify horizontal force per unit length (ΔFx) and assess crustal deviatoric stress caused by variations in Gravitational Potential Energy (ΔGPE) across Sinai Peninsula and its vicinity. Results show ΔFx reaches 2 × 1012 N/m, with deviatoric stress ranging from −20 MPa (compression) in lowland regions (Gulf of Suez and Gulf of Aqaba) to 20 MPa (tension) in central and southern Sinai terrains. This GPE-derived stress, does not account for the far-field tectonic component. Using seismicity data, including Magnitude-Frequency distribution and focal mechanisms, we reveal a predominately extensional stress regimes in the Gulf of Suez, central and southern Sinai, with a strike-slip to transtensional regime in the Gulf of Aqaba. The northward traction of Sinai reduces the impact of GPE-derived compressive stress in Aqaba and Suez, however this motion, supported by geodetic evidences, appears insufficient to relieve the high GPE-derived extensional stress in high-elevation of central and southern Sinai, where it plays an important role. These findings indicate that where plate motions are significant, tectonic stresses dominate over GPE-derived stresses, whereas in more stable zones, GPE contributes significantly. Integrating GPE-based stress calculations with earthquake focal mechanism, seismicity, and previous geodetic studies provides a comprehensive understanding of the prevailing stress regimes and crustal deformation patterns. This approach underscores the complexity of tectonic interactions in Sinai and provides vital input for seismic hazard assessments and geodynamic models.