Bookshelf faulting and horizontal block rotations between overlapping rifts in southern Afar
- Institut de Physique du Globe de Paris (France)
Lateral slip on initially rift-parallel normal faults may be a particularly efficient mechanism to accommodate strain between overlapping oceanic rifts. It occurs in southern Afar, where clockwise block rotations result from distributed dextral shear between the overlapping Ghoubbet Asal-Manda Inakir and Manda Hararo-Abhe Bad rifts. Faulting observed during the 1969, Serdo earthquakes and on SPOT images is consistent with the shear being taken up by left-lateral slip on steep NW-SE striking faults, which formed as normal faults before extensional strain became localized in the two rifts. This bookshelf faulting accounts quantitatively for the 14.5{degree} {plus minus}7.5{degree} rotation documented by paleomagnetism in the 1.8 {plus minus}0.4 Ma old Afar stratoid basalts, given the 17.5 {plus minus}5 mm/yr rate of separation between Arabia and Somalia.
- OSTI ID:
- 5446605
- Journal Information:
- Geophysical Research Letters (American Geophysical Union); (United States), Vol. 17:1; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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