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Detailed Reference Information |
Neves, M.C., Searle, R.C. and Bott, M.H.P. (2003). Easter microplate dynamics. Journal of Geophysical Research 108: doi: 10.1029/2001JB000908. issn: 0148-0227. |
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We use two-dimensional elastic finite element analysis, supplemented by strength estimates, to investigate the driving mechanism of the Easter microplate. Modeled stresses are compared with the stress indicators compiled from earthquake focal mechanisms and structural observations. The objective is to constrain the tectonic forces that govern the Easter microplate rotation and to test the microplate driving hypothesis proposed by Schouten et al. <1993>. We infer that the mantle basal drag cannot drive the microplate rotation but opposes it, and that the asthenospheric viscosity is no more than about 1 ¿ 1018 Pa s. At most, the basal drag comprises 20% of the force resisting microplate rotation. The outward pull of the main plates can drive the rotation by shear drag applied along the northern and southern boundaries of the microplate. However, we propose an additional driving force which arises from the strong variation of the ridge resistance force along the east and west rifts, so that the main driving torques come from the pull of the major plates acting across the narrowing and slowing rifts. This requires the strength to increase substantially toward the rift tips due to thickening of the brittle lithosphere as the spreading rate slows. |
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Abstract |
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Keywords
Tectonophysics, Dynamics of lithosphere and mantle--general, Tectonophysics, Plate motions--general, Tectonophysics, Stresses--crust and lithosphere, Marine Geology and Geophysics, Plate tectonics (8150, 8155, 8157, 8158), Tectonophysics, Rheology--crust and lithosphere |
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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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