Formation and stability of magmatic segments in the Main Ethiopian and Afar rifts

摘要: Abstract As rifting progresses to seafloor spreading, extension within the continental crust commonly is accommodated by a combination of fault slip and dike intrusion. Consistent patterns in spatial arrangement long-lived magma intrusion zones Ethiopian Afar rift sectors, East Africa, suggest that intrusions help localize strain during repeated episodes. Within broad Main Rift, extensional deformation has localized since ∼ 3 m.y. narrow magmatic segments, are oriented oblique orientation Miocene border faults, but (sub-) orthogonal direction. Numerical models combined with geophysical geological observations from Africa used examine viability self-sustaining segmentation. Initiation segments shown result injections, which focus elongated zones. During phases segment evolution weak, stresses at tips, promoting along-axis lengthening. amagmatic extension, numerical predict localization and, lesser extent, broadly distributed zone. This promotes stability; remain preferred location for new phases. These results applied formation maintenance MER The Fentale–Dofen currently non-magmatic phase extension; Dabbahu Red Sea Rift experiencing episode therefore transient cycle. observed instantaneous deformation, seismicity, sometimes propagating beyond tip occur as predicted models.