HR: 08:15h
AN: S21C-02    [Abstracts]
TI: Seismo-tectonics of the Red Sea region in Eritrea: the case of the "transform faults"
AU: * Woldehaimanot, B
EM: Beraki.Woldehaimanot@geologie.uni-freiburg.de
AF: Dept of Earth Sciences, University of Asmara, Asmara, Box 1220 Eritrea
AU: Haileab, B
EM: bhaileab@carleton.edu
AF: Dept of Geology, Carleton College, Northfield, MN 55057 United States
AB: Eritrea is located in the vicinity of the three well recognized seismically active Cenozoic tectonic features in the Horn of Africa, namely, the Red Sea, the East African rift system, and the Gulf of Aden. Within Eritrea, the major seismic source zones identified include: (1) the western margin of the Afar rift, (2) the escarpment, (3) the Massawa channel, (4) the axial trough of the southern Red Sea, (5) the NNW-SSE lineament that connects northern Afar to the axial trough of the Red Sea, and (6) two E-W lineaments that extend onshore from the Red Sea into the Eritrean escarpment. In previous studies the above lineaments have been considered to represent transform faults. However, the absence of well-developed oceanic ridge in the Eritrean segment of the Red Sea and the very low angle (<45) between the orientations of the NNW-SSE lineament and the incipient spreading axis of the Red Sea defy present-day transform fault examples. Fault plane solutions and field observations corresponding to this lineament suggest an E-dipping oblique fault with movement of the hanging wall to the south-east. Similarly, the E-W lineaments, despite being perpendicular to the spreading axis of the Red Sea are characterized by fault plane solutions indicative of normal faults. Fault orientation data (fault plane-striation pair) from these faults also confirm this conclusion and suggest a dip-slip normal fault with hanging wall movement to the south. The lineaments are therefore sites of active normal fault deformation, but not transform faults.
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7250 Transform faults
SC: Seismology [S]
MN: Fall Meeting 2005