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Detailed Reference Information |
Bilham, R., Bendick, R., Larson, K., Mohr, P., Braun, J., Tesfaye, S. and Asfaw, L. (1999). Secular and tidal strain across the Main Ethiopian Rift. Geophysical Research Letters 26: doi: 10.1029/1998GL005315. issn: 0094-8276. |
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Using a combination of laser ranging and GPS data acquired between 1969 and 1997 we derive a separation velocity for the Somali and Nubian plates in Ethiopia (4.5¿1 mm/yr at N108¿10E). This vector is orthogonal to the NNE-trending neotectonic axis (Wonji fault belt) of the Ethiopian rift axis. Current rifting is concentrated within a 33-km-wide zone that includes a 7-km-wide belt of late Quaternary faulting where maximum surface strain rates are comparable to those at active plate boundaries (0.1 &mgr;strain/yr). The strain-field suggests that thin (<5 km) elastic crust separates thick continental lithosphere, a geometry quite different from oceanic rifting, and a mechanical configuration that favors the amplification of regional strain. Semidiurnal strain tides, however, as measured by kinematic GPS methods are not amplified along or across the rift, indicating that the rift zone's low rigidity applies only at periods of years. ¿ 1999 American Geophysical Union |
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Abstract |
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Keywords
Tectonophysics, Dynamics of lithosphere and mantle—general, Geodesy and Gravity, Crustal movements—intraplate, Geodesy and Gravity, Rheology of the lithosphere and mantle, Geodesy and Gravity, Tides—Earth |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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