The dramatic asymmetry in terms of surface elevation, Cenozoic volcanisms and earthquake activity across the Red Sea is an enigmatic issue in global tectonics, partially due to the unavailability of broad-band seismic data on the African Plate adjacent to the Red Sea. Here, we report the first comprehensive image of the mantle transition zone (MTZ) discontinuities using data from the Egyptian National Seismic Network, and compare the resulting depths of the 410 and 660-km discontinuities with those observed on the Arabian side. Our results show that when a standard earth model is used for time-to-depth conversion, the resulting depth of the discontinuities increases systematically towards the axis of the Afro-Arabian Dome (AAD) from both the west and east. Relative to the westernmost area, the maximum depression of the 410-km discontinuity is about 30 km, and that of the 660-km discontinuity is about 45 km. The observed systematic variations can best be explained by a model involving a hydrated MTZ and an upper-mantle low-velocity zone beneath the AAD. Models invoking one or more mantle plumes originated from the MTZ or the lower-mantle beneath the study area are not consistent with the observations.
A. A. Mohamed et al., "Seismic Imaging of Mantle Transition Zone Discontinuities beneath the Northern Red Sea and Adjacent Areas," Geophysical Journal International, vol. 199, no. 2, pp. 648-657, Oxford University Press, Aug 2014.
The definitive version is available at https://doi.org/10.1093/gji/ggu284
Geosciences and Geological and Petroleum Engineering
Center for High Performance Computing Research
Keywords and Phrases
Tectonics; 410-Km Discontinuity; Computational Seismologies; Continental Tectonics; Earthquake Activity; Extensional; Hotspots; Mantle Transition Zone; Systematic Variation; Earthquakes; African Plate; Discontinuity; Extensional Tectonics; Mantle Plume; Mantle Structure; Seismic Data; Seismology; Transition Zone; Egypt; Red Sea [(GVR) Egypt]
International Standard Serial Number (ISSN)
Article - Journal
© 2014 Mohamed, A. A. and Gao, Stephen S. and Elsheikh, A. A. and Liu, Kelly H. and Yu, Youqiang and Fat-Helbary, R. E., All rights reserved.
01 Aug 2014